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The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Jacob T. Murchek, Benjamin J. Drenth, James J. Reitman, Eric D. Anderson, Benjamin P. Magnin, James M. DeGraff · U.S. Geological Survey

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Mineral Resources Program

The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Open-File Report 2025–1019 Version 1.1. July 2025

U.S. Department of the Interior U.S. Geological Survey

The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction By Jacob T. Murchek, Benjamin J. Drenth, James J. Reitman, Eric D. Anderson, Benjamin P. Magnin, and James M. DeGraff

Mineral Resources Program

Open-File Report 2025–1019 Version 1.1. July 2025

U.S. Department of the Interior U.S. Geological Survey

U.S. Geological Survey, Reston, Virginia: 2025

First release: 2025 Revised: July 2025 (ver. 1.1)

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–392–8545. For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov/ or contact the store at 1–888–275–8747. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Murchek, J.T., Drenth, B.J., Reitman, J.J., Anderson, E.D., Magnin, B.P., and DeGraff, J.M., 2025, The feasibility of using lidar-derived digital elevation models for gravity data reduction (ver. 1.1, July 2025): U.S. Geological Survey Open-File Report 2025–1019, 33 p., https://doi.org/10.3133/ofr20251019. ISSN 2331-1258 (online)

iii

Acknowledgments The authors would like to thank Dr. Snehamoy Chatterjee of the Michigan Technological University for his helpful discussion of statistical data analysis; Joshua Nimetz of the U.S. Geological Survey (USGS) for his helpful discussion on lidar data acquisition, processing, and formats; and Anji Shah and Phil Brown of the USGS for their thorough reviews of our manuscript. Val Chandler of the Minnesota Geological Survey was an early proponent of using lidar-derived digital elevation models for gravity work and challenged us to undertake this study.

Contents Acknowledgments��iii Abstract��1 Introduction��1 Gravity Data Acquisition and Reduction��1 Lidar Acquisition and Processing��2 Study Design��3 Results��9 Discussion��12 Recommended Field Practices��12 Conclusion��12 Tables 3–7.......................................................................................................................................................13 References Cited��32

Figures 1.

A schematic of light detection and ranging data acquisition showing an aircraft scanning the Earth’s surface with lidar and revealing lidar topography information while simultaneously receiving global navigation satellite system and inertial measurement unit data��2 Three maps (A–C) showing the 237 gravity stations in the Upper Peninsula of Michigan for which location information was collected as part of regional gravity surveys��4 Two maps (A, B) showing the 198 gravity stations in the western United States (Wyoming and Colorado) for which location information was collected as part of regional gravity surveys��7 A flowchart showing how global navigational satellite system positional data and light detection and ranging data were acquired, processed, and prepared and then how the resulting data for both sets were selected, extracted, and interpreted��9 Two bar graphs (A, B) showing elevation distributions��10

Tables 1.

2. 3. 4. 5.

The minimum number of checkpoints recommended per square kilometer of a light detection and ranging survey from the American Society for Photogrammetry and Remote Sensing (2023)��3 The requirements for different quality-level light detection and ranging data; quality level 2 data are used in this report��3 Location information for the 94 gravity stations located at west-central Upper Peninsula of Michigan from Drenth and Others (2024)��13 Location information for the 87 gravity stations located on the central Upper Peninsula of Michigan from Drenth and others (2024)��17 Location information for the 139 gravity stations located on the Medicine Bow Mountains of Wyoming from Brown and others (2025)��21

Location information for the 59 gravity stations located on the Wet Mountains of Colorado from Magnin and Anderson (2024)��26 7. Location information for the 56 gravity stations located on the Keweenaw Peninsula of Michigan from Murchek and others (2025)��29 8. A statistical breakdown of each study area in this project that shows the average elevation difference observed and the number of points with a difference greater than 1 meter��11

Conversion Factors International System of Units to U.S. customary units

Multiply

To obtain Length

centimeter (cm)

0.3937

inch (in.)

meter (m)

3.281

foot (ft)

kilometer (km)

0.6214

mile (mi)

meter (m)

1.094

yard (yd)

square meter (m2)

10.76

square foot (ft2)

square kilometer (km2)

0.3861

square mile (mi2)

Area

Datums Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88). Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). Elevation, as used in this report, refers to distance above the vertical datum.

vii

Abbreviations 3DEP

3D Elevation Program

ASPRS

American Society for Photogrammetry and Remote Sensing

centimeter

CO–WM

Wet Mountains of Colorado

DEM

digital elevation model

dGNSS

differential global navigational satellite system

GLONASS Globalnaya Navigazionnaya Sputnikovaya Sistema [Global Navigation Satellite System] GNSS

global navigation satellite system

GPS

Global Positioning System

IDW

inverse distance weighted

IMU

inertial measurement unit

kilometer

km2

square kilometer

lidar

light detection and ranging

meter

mGal

milligal

MI–HR

west-central Upper Peninsula of Michigan

MI–KP0

Keweenaw Peninsula of Michigan

MI–TM

central Upper Peninsula of Michigan

NAD 83

North American Datum of 1983

NAVD 88

North American Vertical Datum of 1988

NGS

National Geodetic Survey

NOAA

National Oceanic and Atmospheric Administration

NPD

nominal pulse density

NPS

nominal pulse spacing

quality level

RMSEz

root mean square error in the vertical (z) direction

TIN

triangulated irregular network

upper peninsula

USGS

U.S. Geological Survey

WY–MB

Medicine Bow Mountains of Wyoming

The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction By Jacob T. Murchek,1,2 Benjamin J. Drenth,1 James J. Reitman,1 Eric D. Anderson,1 Benjamin P. Magnin,1 and James M. DeGraff2

Abstract Gravity data require submeter elevation accuracy for data processing, and differential global navigation satellite system (dGNSS) equipment is commonly used to acquire three-dimensional positional data to achieve such accuracy. However, lidar (light detection and ranging) data are commonly used to develop digital elevation models (DEMs) of Earth’s surface. Therefore, using elevations from lidar-derived DEMs for gravity-data acquisition and reduction may improve field efficiency and reduce cost. This study examines the feasibility of using DEMs for gravity-data reduction by comparing dGNSS elevation data from 435 gravity stations in Michigan, Wyoming, and Colorado with their respective DEM elevations. The results show that the average difference between DEM and dGNSS elevations is 13 centimeters (cm) and that 93 percent of those differences are less than 50 cm, even in areas with steep terrain. Because an elevation discrepancy of 50 cm corresponds to an error of roughly 0.1 milligals (mGal) in the simple Bouguer gravity anomaly, the results suggest that lidar-derived DEMs are a viable source for acquiring the elevation data needed to process gravity data, thus improving both the cost and efficiency of data collection for regional surveys where an accuracy of less than 1.0 mGal is desired.

Introduction The gravity geophysical method is a useful, often essential, tool for mapping subsurface geology. Gravity data reduction (processing) relies heavily on accurate and precise elevation measurements, which are often achieved using high-precision (submeter) differential global navigation satellite system (dGNSS) equipment that can determine gravity-station elevations within less than 1 meter. This sort of “surveying grade” dGNSS equipment typically costs tens of thousands of dollars and requires the daily setup of a local base station that must be secured. If the requirement for expensive dGNSS equipment and the corresponding need for a local 1U.S. Geological Survey. 2Michigan Technological University.

base station can be eliminated, gravity data acquisition would become less expensive and more efficient. This report examines the feasibility of using elevations taken from lidar-derived DEMs for use in the reduction of gravity data as a possible replacement for measurements that require the use of expensive dGNSS equipment. The assessment involves comparing gravity-station elevations acquired using high-precision dGNSS equipment with elevations sampled from lidarderived DEMs at the same locations. Nondifferentially corrected horizontal coordinates provided by the dGNSS measurements were used to simulate the effect of data acquisition without using a GNSS base station.

Gravity Data Acquisition and Reduction Gravity data are acquired using gravimeters, which are usually spring-type balances that measure relative gravity by the change of strain (length) on an internal spring (for example, Hinze and others [2012]). A change in gravity causes the displacement of a test mass within these devices that can be nullified by adjusting the spring length to compensate for the test mass displacement. The spring length needed to nullify the balance is then used to calculate the gravity at a specific location. Gravity measurements are taken relative to a base station, where the absolute value of the gravity field intensity is typically known to within 0.1 milligal (mGal). Measurements of variations in the Earth’s gravity field (anomalies) are produced by lateral variations of density within the subsurface (as in Hinze and others [2012]). The measured gravity field is affected by multiple factors, including time-varying factors (such as tides and instrument drift), latitude, elevation, the terrain surrounding the measurement locations (stations), and the density of the Earth. To isolate anomalies produced by local density variations relatable to geology, a series of corresponding corrections must be applied to the observed gravity (for example, Longman [1959] and Blakely [1995]). Accurate elevation measurements are crucial for calculating the free-air and Bouguer gravity anomalies. So, the quality of a gravity survey is heavily dependent on precise elevation control, as an elevation error of 50 centimeters (cm) results in a 0.1 mGal error in the simple Bouguer anomaly.

2 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Lidar Acquisition and Processing Lidar is a remote-sensing method that uses light as a pulsed laser to measure distances to the Earth from an airborne platform (for example, National Oceanic and Atmospheric Administration [NOAA], [2023]). Data are collected from an aircraft with three main components: a laser scanner unit, a global navigation satellite system (GNSS) unit, and an inertial measurement unit (IMU) (Habib and others, 2005; Hollaus and others, 2005; Reutebuch and others, 2005; Webster and Dias, 2006; Pfeifer and Briese, 2007; Liu, 2008). The laser scanner emits pulses around 1,000 nanometers at a near-infrared wavelength (for example, Elaksher [2016]) and contains a receiver that detects the time it takes for the pulsed laser to reach the Earth and return (fig. 1). These reflections are recorded as individual points that define a point cloud, which can be processed to represent locations on the surface of

the Earth (Sugarbaker and others, 2014). The recorded reflections occur from vegetation, the ground surface, and even human-made objects (see Barber and Shortrudge [2004] and Stoker and others [2006]). Therefore, a critical step in lidar processing is ensuring that unwanted artifacts (nonground) are extracted from the data before DEM construction (Liu, 2008). The GNSS unit records the aircraft’s trajectory, and the IMU measures the aircraft’s altitude; both directly influence the accuracy of the lidar points (Webster and Dias, 2006). Analysts supplement and validate the lidar data with groundcontrol checkpoints having known horizontal and vertical positions to ensure horizontal and vertical accuracy. Table 1 gives the minimum number of checkpoints recommended by the American Society for Photogrammetry and Remote Sensing (ASPRS) based on the area of the DEM being constructed; however, these checkpoints may be altered based on the desired quality level (QL) of the DEM (ASPRS, 2023).

Z GNSS

Pitch

IMU Roll

Laser scanner

Yaw

θ = full scan angle Single laser shot GNSS base station

Figure 1. A schematic of light detection and ranging (lidar) data acquisition, modified from National Oceanic and Atmospheric Administration (2012), showing an aircraft scanning the Earth’s surface with lidar and revealing lidar topography information while simultaneously receiving global navigation satellite system (GNSS) and inertial measurement unit data. The full scan angle (θ) from the aircraft and a single laser shot within that scan are shown. A GNSS base station is shown on Earth’s surface.

Lidar Acquisition and Processing 3 The quality level (QL) of a lidar survey is determined by the nominal pulse spacing (NPS) and the vertical positional accuracy, as specified in table 2 (U. S. Geological Survey [USGS], undated.). QL2 lidar-derived DEMs were used for this analysis. Table 1. The minimum number of checkpoints recommended per square kilometer (km2) of a light detection and ranging survey from the American Society for Photogrammetry and Remote Sensing (2023). [≤, less than or equal to]

Area (km2)

Number of checkpoints

≤ 500

501–750

751–1,000

1,001–1,250

1,251–1,500

1,501–1,750

1,751–2,000

2,001–2,250

2,251–2,500

Study Design

Table 2. The requirements for different quality level (QL) light detection and ranging (lidar) data; quality level 2 (QL2) data are used in this report. [This table is modified from the U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) (USGS, undated). cm, centimeter; DEM, digital elevation model; m, meter; NPD, nominal pulse density; NPS, nominal pulse spacing; pts per m2, points per square meter; RMSEz, root mean square error in the vertical (z) direction, QL; quality level; ≤, less than or equal to; ≥, greater than or equal to]

Quality Data level1 source

algorithm to create a surface model from the point-cloud data. The height of each point is compared with its neighbor within the triangle, and points having a significantly higher height than their neighbors are removed (Peucker and others, 1976). After extracting nonground points from the lidar data, a DEM is interpolated based on the remaining ground points. Interpolation is predicting values at an unsampled location using the measured values nearby (for example, Burrough and McDonnell [1998]). DEM interpolation typically uses inverse distance weighted (IDW), spline-based, or geostatistical methods (such as kriging) (Liu, 2008). Once the interpolation method is chosen, a DEM grid is constructed based on the QL of the data.

Vertical accuracy RMSEz (cm)

Nominal pulse spacing (m)

Nominal pulse density (pts per m2)

DEM cell size (m)

QL0

Lidar

≤ 0.35

≥8

0.5

QL1

Lidar

≤ 0.35

≥8

0.5

QL2

Lidar

≤ 0.71

≥2

QL3

Lidar

≤ 1.41

≥ 0.5

1Quality levels are explained in U.S. Geological Survey (undated).

Several methods can be used for extracting nonground points from the raw lidar point-cloud, such as triangulated irregular network (TIN) filtering, slope-based filtering, mathematical morphological filtering, interpolation-based filtering, and machine-learning-based filtering (Cai and others, 2020). The USGS 3D Elevation Program (3DEP) typically requires TIN filtering to assess both the vegetated and nonvegetated vertical accuracy of lidar data (USGS, 2024). TIN filtering uses a triangulation

To study the feasibility of using lidar-derived elevations for gravity-data reduction, we acquired dGNSS elevation data for 435 gravity stations in the Upper Peninsula of Michigan (237 stations, fig. 2A–C), the Wet Mountains of Colorado (59 stations, fig. 3A), and the Medicine Bow Mountains of Wyoming (139 stations, fig. 3B). For each station, Leica Viva GS16 GNSS equipment or a Trimble Geo7x handheld GNSS receiver was used to determine differentially corrected locations (latitude and longitude) and elevations, typically accurate to within 10 cm. To compute differential corrections for the Leica Viva GS16, a GNSS base station located within 25 kilometers (km) of the stations was used. For the Trimble Geo7x, the NOAA Continuously Operating Reference Stations located within 65 km of the gravity stations were used to correct the data differentially. Additionally, GNSS-derived locations were recorded without applying differential corrections to simulate data acquisition conditions without using a GNSS base station. For the lidar comparisons, 1-meter DEM tiles (QL2) were obtained using the USGS LidarExplorer (USGS, 2022; USGS, 2023), the Michigan Technological University Geospatial Research Facility DEM downloader (Sanborn Map Company, Inc., 2020), or the Colorado Hazard Mapping & Risk MAP Portal (Merrick & Company, 2016; Quantum Spatial, Inc., 2020) and were “mosaiced” together in the ArcGIS Pro software package to encompass the entirety of each gravity survey.3 The nondifferentially corrected gravity station coordinates (North American Datum of 1983) were added to ArcGIS Pro, and the DEM was sampled at each station for comparison with the differentially corrected elevation provided by the dGNSS equipment. The flowchart shown in figure 4 describes each data acquisition, processing, and interpretation step. However, it should be noted that the lidar data were acquired and processed before this study. 3Datasets are “mosaiced” or merged using the “Mosaic” tool in the ArcGIS Pro software package.

4 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction A

Figure 2. Three maps (A–C) showing the 237 gravity stations in the Upper Peninsula of Michigan for which location information was collected as part of regional gravity surveys. The stations overlay the mosaiced 1-meter (m) digital elevation model (DEM) rasters obtained from the U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) light detection and ranging (lidar) data in the National Map Downloader (USGS, 2022) or the Michigan Technological University Geospatial Research Facility DEM tool (Sanborn Map Company, Inc., 2020). (A) Map showing the 56 gravity stations in the Keweenaw Peninsula of Michigan (MI–KP0) where location data were collected with a Global Navigational Satellite System (GNSS) receiver. Elevation data are from 0 to 450 m. (B) Map showing the 94 gravity stations in the west-central Upper Peninsula of Michigan (MI–HR) where location information was collected with GNSS equipment. Elevation data are from 400 to 600 m. (C) Map showing the 87 gravity stations in the central Upper Peninsula of Michigan (MI–TM) where location information was collected with GNSS equipment. Elevation data are from 150 to 300 m. The prefixes discussed here—MI–KP0, MI–HR, and MI–TM—represent the location aspect of the gravity station numbers in tables 3, 4, and 7 (at the end of this report). ft, foot.

Lidar Acquisition and Processing 5 B

Figure 2.—Continued

6 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction C

Figure 2.—Continued

20 KILOMETERS

Lidar Acquisition and Processing 7 A

20 KILOMETERS

Figure 3. Two maps (A, B) showing the 198 gravity stations in the western United States (Wyoming and Colorado) for which location information was collected as part of regional gravity surveys. The stations overlay the mosaiced 1-meter (m) digital elevation model (DEM) rasters. Light detection and ranging (lidar) data were obtained from two sources. U.S. Geological Survey (USGS) 3D Elevation Program lidar data were retrieved from the USGS National Map Downloader (USGS, 2024). Lidar data from Merrick & Company (2016) and Quantum Spatial, Inc. (2020) were retrieved from the Colorado Hazard Mapping & Risk MAP Portal (Merrick & Company, 2016). (A) Map showing the 59 gravity stations in the Wet Mountains of Colorado (CO–WM) where location information was collected with Global Navigational Satellite System (GNSS) equipment. Elevation data are from 2,000 to 4,000 m. (B) Map showing the 139 gravity stations in the Medicine Bow Mountains of Wyoming (WY–MB) where location information was collected with GNSS equipment. Elevation data are from 2,000 to 4,000 m. The prefixes discussed here—CO–WM and WY– MB—represent the location aspect of the gravity station numbers in tables 5 and 6 (at the end of this report). ft, foot.

8 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction B

Figure 3.—Continued

20 KILOMETERS

Lidar Acquisition and Processing 9

GNSS Posi�onal Data Data Acquisi�on Eleva�on data collected at gravity sta�on using diﬀeren�al GNSS equipment

Data Processing GNSS data post-processed to determine both nondiﬀeren�ally and diﬀeren�ally corrected loca�ons

Data Prepara�on Tables of data prepared and loaded as point data (NAD83)

Lidar Data Acquisi�on Airborne lidar point cloud data collected prior to study Data Interpreta�on Data were exported for sta�s�cal analysis

Data Extrac�on The DEMs were sampled at each gravity sta�on loca�on and a column with the DEM eleva�on for each sta�on was created

Data Selec�on Data points selected for each gravity survey. Data outside DEM coverage ﬁltered out

Data Processing Ar�facts removed and bare Earth surface iden�ﬁed. 1meter DEM created

Data Prepara�on 1-meter DEM �les for each study area were downloaded and mosaiced

Figure 4. A flowchart showing how global navigational satellite system (GNSS) positional data and light detection and ranging (lidar) data were acquired, processed, and prepared and then how the resulting data for both sets were selected, extracted, and interpreted. DEM, digital elevation model; NAD 83, North American Datum of 1983.

Results The elevation differences between the dGNSS measurements and DEMs were consistently (93 percent) less than 50 cm, corresponding to a 0.1 mGal error in the simple Bouguer gravity anomaly. Horizontal and vertical positions for all 435 gravity stations are shown in tables 3–7 (at the end of the report) with their respective lidar-derived elevation and the differences between the GNSS and lidar-derived elevations. The distribution of differences between DEM and GNSS elevations is shown in figure 5A, and the distribution of their absolute differences is shown in figure 5B. The mean difference between the GNSS and DEMderived elevations is 13 cm with a standard deviation of 46 cm. Approximately 93 percent (N = 406) of the data

points fall within 1 standard deviation of the mean (minimum –33 cm; maximum 59 cm). The lower limit for the 95 percent confidence interval is 9 cm, and the upper limit is 17 cm. A maximum positive difference of 3.9 meters (m) and a maximum negative difference of –2.1 m occur in the central Upper Peninsula. However, the mean elevation difference in the Upper Peninsula is 8 cm, a measure less than the average in Colorado and Wyoming (20 cm), which contain steep terrain. Overall, 97 percent (N = 423) of the 435 stations exhibit an elevation difference of less than 1 m. The statistical breakdown for each study area is shown in table 8.

10 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction A

200

GNSS Elevations - DEM Elevations Mean = 0.13 Std Dev = 0.46 96% Confidence interval for mean [0.08, 0.17]

46%

Number of measurements

−σ

+σ

150 29%

100

15%

2% ~1%

~1%

0 −2.5

−2.0

−1.5

−1.0

−0.5

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Elevation differences, in meters

Figure 5. Two bar graphs (A, B) showing elevation distributions. (A) Bar graph that shows the distribution (mean = 0.13, standard deviation = 0.46) of elevation differences (global navigational satellite system minus light detection and ranging [GNSS – lidar]) and indicates that 93 percent of the data fall within 1 standard deviation (σ) of the mean (μ) (13 centimeters [cm]). (B) Bar graph that shows the distribution (mean = 0.22, standard deviation = 0.42) of the absolute value of the elevation differences (|GNSS – lidar|) and a mean difference of 22 cm in the absolute differences observed within the data. %, percent; m, meter.

Lidar Acquisition and Processing 11 GNSS Elevations - DEM Elevations

Mean = 0.22 Std Dev = 0.42 95% Confidence interval for mean [0.18, 0.26]

75%

300 +σ

200

100

29%

3% 0

~1%

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Number of measurements

−σ

Absolute elevation differences, in meters

Figure 5.—Continued

Table 8. A statistical breakdown of each study area in this project that shows the average elevation difference observed and the number of points with a difference greater than 1 meter (m). [UP, upper peninsula ; > greater than]

Mean elevation difference (m)

Standard deviation

Minimum (m)

Maximum (m)

No. of points >1 m elevation difference

Medicine Bow Mountains, Wyoming

0.25

0.37

–0.39

3.1

Wet Mountains, Colorado

0.11

0.53

–0.93

3.7

Keweenaw Peninsula, Michigan

0.26

0.47

–0.07

2.7

West-central UP, Michigan

–0.07

0.17

–0.66

0.54

Central UP, Michigan

0.11

0.62

–2.1

3.9

Total UP, Michigan (less-steep terrain)

0.08

0.44

–2.1

3.9

Total Wyoming and Colorado (steep terrain)

0.20

0.42

–0.93

3.7

Location

Regional totals

12 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Discussion Of the 435 gravity stations, 406 (approximately 93 percent) lidar-derived elevations fall within ±50 cm of the dGNSS elevations, meaning that their use would produce an error of less than 0.1 mGal in the simple Bouguer anomaly. Regional gravity surveys commonly focus on mapping anomalies greater than 1 mGal, so an error of 0.1 mGal is not a cause for concern in most cases. Moreover, most absolute base (reference) stations used for gravity-data reduction have an uncertainty of ±0.1 mGal (for example, Morelli and others [1972]). Therefore, this study shows that lidar-derived elevations are sufficiently accurate for regional gravity-data reduction, and, in most cases, their use produces errors comparable to the inherent absolute accuracy of standard regional gravity surveys. For detailed gravity surveys focused on smaller anomalies—those with an accuracy of less than 0.1 mGal—dGNSS equipment may be necessary. Only 12 gravity stations (less than 3 percent) had elevation differences greater than 1 m between dGNSS and lidar-derived elevations. Seven were in the Upper Peninsula of Michigan, four were in the Medicine Bow Mountains of Wyoming, and one was in the Wet Mountains of Colorado. To identify the sources of these discrepancies, we examined the elevation differences between the lidar-derived elevations and dGNSS elevations using the differentially corrected horizontal coordinates in the Medicine Bow Mountains. The average elevation difference between the measurements was roughly 1-cm less than when the nondifferentially corrected coordinates were used, and the same four stations showed an elevation difference of greater than 1 m. This observation indicates that the four largest elevation discrepancies are not likely related to the lack of differential processing for the horizontal coordinates. Instead, these discrepancies may result from dense vegetation causing a multipath in the GNSS signal, a locally steep elevation gradient, or an unknown error in the dGNSS-derived elevations.

Recommended Field Practices The use of several recommendations may optimize positional data acquisition for gravity data processing and yield acceptable uncertainty in simple Bouguer gravity values. GNSS equipment (for example, a handheld, non-dGNSS unit) with the ability to detect both Global Positioning System (GPS) and Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS)4 satellites is recommended for obtaining the best possible horizontal position data, especially at higher latitudes where GPS readings are less accurate. Horizontal positional errors may result in the gravity station being mislocated by more than several meters, thus producing elevation inaccuracies. For this 4The “Global Navigation Satellite System” is a Russian satellite-based navigation system that provides position information.

reason, placing gravity stations in areas more than 5 m away from steep topographic slopes (such as a locally flat surface) is recommended. The reduction or elimination of multipaths is also necessary for optimizing positional accuracy during data acquisition. A multipath can result from the primary GNSS signal reflecting off buildings, vegetation, or mountains, or from atmospheric scattering. A reduction of this effect can be achieved by placing the GNSS antenna in an elevated position, such as on the roof of a vehicle or a range pole and away from areas with dense vegetation. Placing stations on small platforms above the ground’s surface can also cause inaccuracies in the lidar-derived elevation and should be avoided.

Conclusion This study evaluated whether lidar-derived DEMs could serve as elevation control for gravity surveys to reduce cost and improve field efficiency. Elevation data from 435 gravity stations in the Upper Peninsula of Michigan, the Medicine Bow Mountains of Wyoming, and the Wet Mountains of Colorado were compared with elevations from a 1-m horizontal-resolution DEM for each station. An average difference of 13 cm between dGNSS and DEM elevations was observed, with a standard deviation of 46 cm. Over 93 percent of the DEM data were within 50 cm of GNSS data, corresponding to a simple Bouguer gravity error of approximately 0.1 mGal. These results indicate that lidar-derived DEMs provide acceptable elevation control for gravity data reduction, particularly for regional gravity surveys where anomalies of interest are usually greater than 1 mGal in amplitude. In detailed surveys requiring greater accuracy and precision, other means of determining elevations may be required. Twelve stations exhibited elevation differences between dGNSS and DEM data greater than 1 m. The source of this relatively rare discrepancy is unknown but may be related to dense vegetation cover, locally steep elevation gradients, or an unknown error in the dGNSS elevations. This study suggests that using QL2 lidar-derived DEMs for gravity-data reduction is acceptable for most regional surveys.

Tables 3–7 Table 3. Location information for the 94 gravity stations located at west-central Upper Peninsula of Michigan (MI–HR) from Drenth and Others (2024). [“Gravity station” refers to a unique identifier that is based on the station number used in the data source for this table. “UC LAT” and “UC LON” refer to the horizontal coordinates before differential correction. “DC LAT” and “DC LON” refer to the differentially corrected horizontal coordinates. “DGNSS ELEV” refers to the elevation data from the differential global navigation satellite system (dGNSS) equipment from the differentially corrected coordinates. “LIDAR ELEV” refers to the light detection and ranging (lidar) derived elevation from the 1-meter (m) digital elevation model (DEM). “ELEV DIFF” refers to the elevation difference (dGNSS – lidar), and “ABS ELEV DIFF” refers to the absolute value of this difference. NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988]

Gravity station

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

46.42494

–88.16299

46.42493

–88.16300

523.87

523.74

0.13

46.43683

–88.16355

46.43681

–88.16355

538.11

538.10

0.01

MI–HR211

46.44739

–88.16216

46.44738

–88.16216

531.44

531.10

0.35

MI–HR212

46.46448

–88.17829

46.46448

–88.17830

544.78

544.73

0.04

MI–HR213

46.43243

–88.18091

46.43242

–88.18092

525.93

525.81

0.12

MI–HR214

46.43118

–88.19405

46.43117

–88.19406

514.27

0.00

MI–HR215

46.42438

–88.21213

46.42439

–88.21215

515.77

515.53

0.24

MI–HR216

46.42267

–88.22513

46.42266

–88.22513

536.88

536.80

0.09

MI–HR217

46.41882

–88.24124

46.41881

–88.24127

534.57

534.72

–0.15

0.15

MI–HR218

46.43243

–88.22989

46.43243

–88.22991

543.09

543.01

0.08

MI–HR219

46.44121

–88.23626

46.44121

–88.23627

540.62

540.19

0.43

MI–HR220

46.45163

–88.23310

46.45164

–88.23311

534.12

534.74

–0.62

0.62

MI–HR221

46.45329

–88.21923

46.45330

–88.21922

525.97

525.43

0.54

MI–HR222

46.43917

–88.21494

46.43918

–88.21494

528.55

528.60

–0.05

0.05

MI–HR223

46.44226

–88.18349

46.44227

–88.18349

529.38

0.00

MI–HR239

46.44133

–88.08456

46.44131

–88.08455

510.37

510.46

–0.10

0.10

MI–HR240

46.44881

–88.07866

46.44879

–88.07865

511.92

511.90

0.02

MI–HR241

46.46879

–88.08052

46.46877

–88.08051

478.68

478.89

–0.21

0.21

MI–HR242

46.45943

–88.08535

46.45941

–88.08534

472.61

472.67

–0.06

0.06

MI–HR243

46.45848

–88.09835

46.45848

–88.09833

479.39

479.48

–0.09

0.09

MI–HR244

46.46113

–88.10863

46.46113

–88.10862

498.09

498.04

0.06

MI–HR245

46.46627

–88.11848

46.46626

–88.11848

521.55

521.60

–0.05

0.05

MI–HR246

46.47889

–88.12047

46.47888

–88.12046

525.69

525.75

–0.06

0.06

MI–HR247

46.45086

–88.10303

46.45085

–88.10303

492.13

492.27

–0.14

0.14

MI–HR248

46.44016

–88.11112

46.44014

–88.11112

486.16

486.13

0.02

Tables 3–7 13

MI–HR209 MI–HR210

[“Gravity station” refers to a unique identifier that is based on the station number used in the data source for this table. “UC LAT” and “UC LON” refer to the horizontal coordinates before differential correction. “DC LAT” and “DC LON” refer to the differentially corrected horizontal coordinates. “DGNSS ELEV” refers to the elevation data from the differential global navigation satellite system (dGNSS) equipment from the differentially corrected coordinates. “LIDAR ELEV” refers to the light detection and ranging (lidar) derived elevation from the 1-meter (m) digital elevation model (DEM). “ELEV DIFF” refers to the elevation difference (dGNSS – lidar), and “ABS ELEV DIFF” refers to the absolute value of this difference. NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988]

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

MI–HR249

46.43465

–88.12686

46.43464

–88.12685

508.44

508.33

0.11

MI–HR250

46.44574

–88.12259

46.44573

–88.12259

508.40

0.00

MI–HR251

46.45507

–88.12062

46.45507

–88.12063

512.48

512.41

0.08

MI–HR252

46.45011

–88.06530

46.45011

–88.06529

471.30

471.16

0.14

MI–HR253

46.44357

–88.05018

46.44357

–88.05017

465.11

465.32

–0.21

0.21

MI–HR254

46.42801

–88.05931

46.42801

–88.05930

497.72

0.00

MI–HR255

46.43435

–88.03451

46.43434

–88.03450

457.50

457.70

–0.20

0.20

MI–HR256

46.42357

–88.02001

46.42358

–88.02000

457.56

457.47

0.09

MI–HR257

46.41524

–88.00702

46.41523

–88.00701

461.07

461.20

–0.13

0.13

MI–HR258

46.43268

–88.09584

46.43266

–88.09583

519.07

519.20

–0.13

0.13

MI–HR259

46.42517

–88.10726

46.42517

–88.10726

509.49

509.43

0.06

MI–HR260

46.41580

–88.11487

46.41580

–88.11487

511.05

511.11

–0.07

0.07

MI–HR261

46.40543

–88.11949

46.40543

–88.11949

503.56

503.58

–0.02

0.02

MI–HR262

46.40569

–88.11962

46.40569

–88.11961

503.74

503.75

0.00

MI–HR263

46.39486

–88.11466

46.39486

–88.11466

490.43

490.56

–0.13

0.13

MI–HR265

46.42661

–88.09738

46.42660

–88.09738

524.72

524.96

–0.24

0.24

MI–HR266

46.41892

–88.08438

46.41892

–88.08436

508.71

508.78

–0.07

0.07

MI–HR267

46.43559

–88.05164

46.43558

–88.05165

499.46

499.57

–0.11

0.11

MI–HR268

46.41399

–88.02718

46.41398

–88.02718

475.55

475.52

0.04

MI–HR269

46.41310

–88.01249

46.41309

–88.01248

472.11

472.25

–0.13

0.13

MI–HR270

46.41278

–87.99475

46.41277

–87.99474

457.07

457.03

0.04

MI–HR271

46.40503

–87.98644

46.40502

–87.98643

456.36

456.40

–0.04

0.04

MI–HR272

46.39359

–87.99155

46.39358

–87.99154

462.14

462.16

–0.01

0.01

MI–HR273

46.39923

–88.01748

46.39922

–88.01748

457.80

457.90

–0.10

0.10

MI–HR274

46.38052

–88.02036

46.38051

–88.02037

461.31

0.00

MI–HR275

46.38799

–88.00558

46.38799

–88.00558

456.66

456.70

–0.04

0.04

MI–HR276

46.39172

–88.09548

46.39171

–88.09546

505.30

505.39

–0.09

0.09

MI–HR277

46.39956

–88.08134

46.39956

–88.08134

514.50

514.63

–0.12

0.12

Gravity station

14 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Table 3. Location information for the 94 gravity stations located at west-central Upper Peninsula of Michigan (MI–HR) from Drenth and Others (2024).—Continued

Table 3. Location information for the 94 gravity stations located at west-central Upper Peninsula of Michigan (MI–HR) from Drenth and Others (2024).—Continued [“Gravity station” refers to a unique identifier that is based on the station number used in the data source for this table. “UC LAT” and “UC LON” refer to the horizontal coordinates before differential correction. “DC LAT” and “DC LON” refer to the differentially corrected horizontal coordinates. “DGNSS ELEV” refers to the elevation data from the differential global navigation satellite system (dGNSS) equipment from the differentially corrected coordinates. “LIDAR ELEV” refers to the light detection and ranging (lidar) derived elevation from the 1-meter (m) digital elevation model (DEM). “ELEV DIFF” refers to the elevation difference (dGNSS – lidar), and “ABS ELEV DIFF” refers to the absolute value of this difference. NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988]

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

MI–HR278

46.39919

–88.06436

46.39920

–88.06434

498.56

498.47

0.09

MI–HR279

46.40759

–88.05725

46.40758

–88.05723

488.88

0.01

MI–HR280

46.41484

–88.06662

46.41484

–88.06661

493.27

493.31

–0.04

0.04

MI–HR281

46.40704

–88.04444

46.40703

–88.04443

477.41

477.68

–0.27

0.27

MI–HR282

46.38617

–88.04290

46.38617

–88.04290

474.39

474.54

–0.15

0.15

MI–HR283

46.39784

–88.04632

46.39783

–88.04632

476.50

476.69

–0.18

0.18

MI–HR284

46.38457

–88.08025

46.38456

–88.08025

507.73

507.89

–0.16

0.16

MI–HR285

46.37563

–88.07300

46.37561

–88.07301

501.87

502.09

–0.22

0.22

MI–HR286

46.37335

–88.05530

46.37333

–88.05530

482.75

482.83

–0.08

0.08

MI–HR287

46.37545

–88.03577

46.37543

–88.03578

471.54

471.62

–0.08

0.08

MI–HR288

46.37665

–88.08606

46.37664

–88.08606

507.56

507.64

–0.08

0.08

MI–HR289

46.37673

–88.09903

46.37672

–88.09903

495.34

495.37

–0.03

0.03

MI–HR290

46.37274

–88.10606

46.37273

–88.10606

488.82

488.87

–0.05

0.05

MI–HR291

46.37188

–88.11852

46.37187

–88.11853

479.97

480.05

–0.08

0.08

MI–HR301

46.41593

–87.98031

46.41594

–87.98032

482.42

482.41

0.01

MI–HR302

46.41762

–87.96272

46.41761

–87.96274

474.48

474.78

–0.30

0.30

MI–HR303

46.42835

–87.95810

46.42835

–87.95812

466.70

466.94

–0.24

0.24

MI–HR304

46.42658

–87.93938

46.42657

–87.93940

465.76

465.84

–0.08

0.08

MI–HR305

46.42620

–87.92179

46.42620

–87.92181

462.74

462.75

0.00

MI–HR306

46.42973

–87.90791

46.42970

–87.90793

461.32

461.42

–0.11

0.11

MI–HR307

46.44103

–87.91421

46.44099

–87.91423

477.03

476.99

0.04

MI–HR308

46.42258

–87.89031

46.42254

–87.89032

456.78

456.92

–0.14

0.14

MI–HR309

46.42578

–87.87663

46.42575

–87.87665

459.60

459.74

–0.15

0.15

MI–HR310

46.41063

–87.89066

46.41060

–87.89066

457.74

457.91

–0.17

0.17

MI–HR311

46.41775

–87.92782

46.41772

–87.92783

460.52

460.70

–0.18

0.18

MI–HR312

46.40566

–87.92574

46.40565

–87.92576

464.99

465.32

–0.33

0.33

MI–HR313

46.40483

–87.96428

46.40484

–87.96430

465.96

466.39

–0.43

0.43

MI–HR314

46.39421

–87.95238

46.39421

–87.95241

467.12

467.40

–0.27

0.27

Tables 3–7 15

UC LAT (NAD 83)

Gravity station

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

MI–HR315

46.38814

–87.93001

46.38815

–87.93003

465.65

465.94

–0.29

0.29

MI–HR316

46.38068

–87.91778

46.38070

–87.91779

459.97

460.14

–0.16

0.16

MI–HR317

46.36793

–87.90407

46.36795

–87.90407

454.28

454.45

–0.17

0.17

MI–HR318

46.35638

–87.89669

46.35640

–87.89667

456.48

457.15

–0.66

0.66

MI–HR319

46.34743

–87.87883

46.34744

–87.87881

451.22

451.53

–0.31

0.31

MI–HR320

46.33948

–87.89772

46.33949

–87.89771

454.00

454.09

–0.09

0.09

MI–HR321

46.34497

–87.91396

46.34498

–87.91394

458.56

458.65

–0.09

0.09

MI–HR322

46.34791

–87.93149

46.34791

–87.93146

452.12

452.42

–0.30

0.30

MI–HR323

46.36046

–87.93067

46.36046

–87.93065

455.94

456.20

–0.26

0.26

MI–HR324

46.37647

–87.93349

46.37646

–87.93346

460.19

460.06

0.14

MI–HR325

46.40201

–87.99925

46.40202

–87.99923

481.08

481.11

–0.03

0.03

MI–HR326

46.37824

–87.98663

46.37825

–87.98662

451.77

451.76

0.01

MI–HR327

46.36282

–87.97087

46.36284

–87.97084

447.92

448.19

–0.27

0.27

Gravity station

16 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Table 3. Location information for the 94 gravity stations located at west-central Upper Peninsula of Michigan (MI–HR) from Drenth and Others (2024).—Continued

Table 4. Location information for the 87 gravity stations located on the central Upper Peninsula of Michigan (MI–TM) from Drenth and others (2024). [“Gravity station” refers to a unique identifier that is based on the station number used in the data source for this table. “UC LAT” and “UC LON” refer to the horizontal coordinates before differential correction. “DC LAT” and “DC LON” refer to the differentially corrected horizontal coordinates. “DGNSS ELEV” refers to the elevation data from the differential global navigation satellite system (dGNSS) equipment from the differentially corrected coordinates. “LIDAR ELEV” refers to the light detection and ranging (lidar) derived elevation from the 1-meter (m) digital elevation model (DEM). “ELEV DIFF” refers to the elevation difference (dGNSS – lidar), and “ABS ELEV DIFF” refers to the absolute value of this difference. NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988]

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

MI–TM001

46.05761

–86.76523

46.05760

–86.76523

228.46

228.55

–0.10

0.10

MI–TM002

46.05005

–86.77984

46.05004

–86.77984

237.26

237.29

–0.04

0.04

MI–TM003

46.04471

–86.79793

46.04470

–86.79792

235.38

235.29

0.09

MI–TM004

46.03561

–86.82491

46.03561

–86.82492

231.49

231.54

–0.05

0.05

MI–TM005

46.05917

–86.82250

46.05919

–86.82249

231.44

233.53

–2.09

2.09

MI–TM006

46.10298

–86.76241

46.10298

–86.76243

240.67

240.74

–0.07

0.07

MI–TM007

46.12079

–86.75999

46.12079

–86.76001

250.59

250.52

0.07

MI–TM008

46.13699

–86.75775

46.13700

–86.75778

243.03

243.05

–0.01

0.01

MI–TM009

46.14718

–86.78123

46.14719

–86.78124

240.63

240.60

0.02

MI–TM010

46.14721

–86.80917

46.14722

–86.80918

242.80

242.83

–0.02

0.02

MI–TM011

46.15373

–86.83689

46.15373

–86.83691

237.25

237.29

–0.04

0.04

MI–TM012

46.13682

–86.83782

46.13683

–86.83782

248.12

247.11

1.01

MI–TM013

46.11941

–86.83631

46.11941

–86.83633

243.01

243.11

–0.10

0.10

MI–TM014

46.10464

–86.83439

46.10466

–86.83442

228.64

228.71

–0.07

0.07

MI–TM015

46.09690

–86.86844

46.09690

–86.86845

214.65

214.68

–0.04

0.04

MI–TM016

46.08374

–86.84393

46.08374

–86.84394

231.24

231.25

–0.02

0.02

MI–TM017

46.06476

–86.85307

46.06475

–86.85306

232.13

231.87

0.26

MI–TM018

46.04313

–86.85153

46.04314

–86.85154

230.66

230.67

–0.01

0.01

MI–TM019

46.02522

–86.86199

46.02522

–86.86200

224.94

225.03

–0.09

0.09

MI–TM020

46.02190

–86.83746

46.02190

–86.83748

228.33

228.41

–0.08

0.08

MI–TM021

46.09679

–86.77856

46.09679

–86.77857

243.10

242.94

0.16

MI–TM022

46.07565

–86.77473

46.07564

–86.77473

237.34

237.23

0.11

MI–TM023

46.04142

–86.75639

46.04141

–86.75639

215.18

0.00

MI–TM024

46.02985

–86.73892

46.02984

–86.73893

231.27

231.18

0.09

MI–TM025

46.03102

–86.71163

46.03102

–86.71163

229.00

228.94

0.06

MI–TM026

46.04420

–86.71386

46.04421

–86.71387

230.28

230.34

–0.07

0.07

MI–TM027

46.02166

–86.69368

46.02168

–86.69369

230.49

230.47

0.02

MI–TM028

46.01128

–86.67806

46.01129

–86.67808

230.95

230.94

0.01

Tables 3–7 17

UC LAT (NAD 83)

Gravity station

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

MI–TM029

46.01631

–86.65150

46.01633

–86.65150

229.18

0.00

MI–TM030

46.02011

–86.62713

46.02013

–86.62713

238.58

234.70

3.89

MI–TM031

46.03034

–86.60562

46.03034

–86.60562

232.86

232.85

0.01

MI–TM032

46.04037

–86.58267

46.04037

–86.58268

233.50

233.46

0.04

MI–TM033

46.04585

–86.56003

46.04586

–86.56004

233.23

233.06

0.17

MI–TM034

46.04844

–86.52518

46.04844

–86.52518

231.52

231.51

0.01

MI–TM035

46.06206

–86.54437

46.06206

–86.54437

234.53

234.51

0.02

MI–TM036

46.07869

–86.54662

46.07871

–86.54663

237.41

237.31

0.10

MI–TM037

46.09413

–86.54977

46.09414

–86.54978

239.60

239.56

0.04

MI–TM038

46.11218

–86.55485

46.11219

–86.55486

244.43

244.38

0.05

MI–TM039

46.13041

–86.55865

46.13043

–86.55866

247.42

247.39

0.02

MI–TM040

46.14352

–86.55224

46.14354

–86.55226

255.16

255.02

0.13

MI–TM041

46.15762

–86.55333

46.15763

–86.55333

253.88

253.87

0.01

MI–TM042

46.15343

–86.58112

46.15343

–86.58114

242.02

242.12

–0.10

0.10

MI–TM043

46.15213

–86.60946

46.15214

–86.60948

240.03

240.05

–0.02

0.02

MI–TM044

46.07875

–86.74031

46.07874

–86.74032

237.59

236.63

0.95

MI–TM045

46.07712

–86.69008

46.07711

–86.69009

278.00

278.33

–0.32

0.32

MI–TM046

46.09977

–86.67117

46.09976

–86.67117

249.36

249.29

0.07

MI–TM047

46.11141

–86.67072

46.11143

–86.67073

239.36

239.24

0.11

MI–TM048

46.06748

–86.71794

46.06747

–86.71797

231.27

231.28

0.00

MI–TM049

46.07899

–86.72260

46.07900

–86.72261

235.34

0.00

MI–TM050

46.06587

–86.74520

46.06587

–86.74521

223.32

223.30

0.02

MI–TM051

46.02779

–86.66780

46.02781

–86.66781

242.08

242.04

0.04

MI–TM052

46.04770

–86.65981

46.04770

–86.65981

249.52

249.51

0.01

MI–TM053

46.04221

–86.63906

46.04224

–86.63907

240.68

240.27

0.41

MI–TM054

46.06501

–86.64277

46.06502

–86.64278

245.66

245.55

0.11

MI–TM055

46.08670

–86.64203

46.08671

–86.64204

248.09

0.00

MI–TM056

46.10423

–86.63742

46.10425

–86.63741

253.69

252.71

0.98

Gravity station

18 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Table 4. Location information for the 87 gravity stations located on the central Upper Peninsula of Michigan (MI–TM) from Drenth and others (2024).—Continued

Table 4. Location information for the 87 gravity stations located on the central Upper Peninsula of Michigan (MI–TM) from Drenth and others (2024).—Continued [“Gravity station” refers to a unique identifier that is based on the station number used in the data source for this table. “UC LAT” and “UC LON” refer to the horizontal coordinates before differential correction. “DC LAT” and “DC LON” refer to the differentially corrected horizontal coordinates. “DGNSS ELEV” refers to the elevation data from the differential global navigation satellite system (dGNSS) equipment from the differentially corrected coordinates. “LIDAR ELEV” refers to the light detection and ranging (lidar) derived elevation from the 1-meter (m) digital elevation model (DEM). “ELEV DIFF” refers to the elevation difference (dGNSS – lidar), and “ABS ELEV DIFF” refers to the absolute value of this difference. NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988]

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

MI–TM057

46.16162

–86.75468

46.16161

–86.75469

245.85

245.96

–0.12

0.12

MI–TM058

46.17326

–86.72937

46.17326

–86.72939

241.60

241.64

–0.04

0.04

MI–TM059

46.15155

–86.72839

46.15156

–86.72840

241.30

241.38

–0.09

0.09

MI–TM060

46.12253

–86.69312

46.12254

–86.69314

258.60

258.57

0.04

MI–TM061

46.13349

–86.68783

46.13351

–86.68784

239.11

239.13

–0.02

0.02

MI–TM062

46.14831

–86.70171

46.14833

–86.70173

237.16

237.11

0.05

MI–TM063

46.16396

–86.69830

46.16397

–86.69831

238.12

238.16

–0.04

0.04

MI–TM064

46.15843

–86.67672

46.15844

–86.67673

255.73

–0.01

0.01

MI–TM065

46.16060

–86.65028

46.16063

–86.65029

245.13

0.01

MI–TM066

46.14994

–86.62531

46.14995

–86.62532

259.00

259.06

–0.06

0.06

MI–TM067

46.12999

–86.60514

46.13001

–86.60516

259.66

258.78

0.88

MI–TM068

46.13003

–86.57811

46.13004

–86.57811

251.35

251.37

–0.02

0.02

MI–TM069

46.11426

–86.58261

46.11428

–86.58263

248.29

248.27

0.02

MI–TM070

46.11179

–86.60224

46.11181

–86.60225

252.11

0.00

MI–TM071

46.10062

–86.58400

46.10063

–86.58401

245.12

245.04

0.09

MI–TM072

46.08423

–86.59097

46.08424

–86.59097

240.72

240.70

0.02

MI–TM073

46.07043

–86.57232

46.07044

–86.57232

236.64

236.62

0.02

MI–TM074

46.05627

–86.59073

46.05627

–86.59074

235.12

235.84

–0.71

0.71

MI–TM075

46.11936

–86.63511

46.11935

–86.63514

243.36

243.68

–0.32

0.32

MI–TM076

46.14429

–86.65346

46.14430

–86.65349

243.00

242.59

0.41

MI–TM077

46.14126

–86.63864

46.14127

–86.63868

252.68

251.23

1.45

MI–TM078

46.12989

–86.80151

46.12989

–86.80151

245.00

245.02

–0.02

0.02

MI–TM079

46.16822

–86.83967

46.16821

–86.83969

239.68

239.76

–0.08

0.08

MI–TM080

46.18263

–86.83808

46.18263

–86.83810

251.87

248.97

2.90

MI–TM081

46.19654

–86.83722

46.19654

–86.83725

247.93

247.95

–0.03

0.03

MI–TM082

46.16161

–86.79492

46.16161

–86.79493

246.17

246.19

–0.02

0.02

MI–TM083

46.17095

–86.77776

46.17096

–86.77777

245.68

245.66

0.02

MI–TM084

46.18688

–86.78758

46.18689

–86.78760

245.01

245.08

–0.07

0.07

Tables 3–7 19

UC LAT (NAD 83)

Gravity station

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

MI–TM085

46.17720

–86.75986

46.17722

–86.75988

241.53

241.41

0.12

MI–TM086

46.19373

–86.77394

46.19374

–86.77395

245.13

245.18

–0.05

0.05

MI–TM087

46.20733

–86.79234

46.20736

–86.79234

248.92

248.74

0.19

Gravity station

20 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Table 4. Location information for the 87 gravity stations located on the central Upper Peninsula of Michigan (MI–TM) from Drenth and others (2024).—Continued

Table 5. Location information for the 139 gravity stations located on the Medicine Bow Mountains of Wyoming (WY–MB) from Brown and others (2025). [“Gravity station” refers to a unique identifier that is based on the station number used in the data source for this table. “UC LAT” and “UC LON” refer to the horizontal coordinates before differential correction. “DC LAT” and “DC LON” refer to the differentially corrected horizontal coordinates. “DGNSS ELEV” refers to the elevation data from the differential global navigation satellite system (dGNSS) equipment from the differentially corrected coordinates. “LIDAR ELEV” refers to the light detection and ranging (lidar) derived elevation from the 1-meter (m) digital elevation model (DEM). “ELEV DIFF” refers to the elevation difference (dGNSS – lidar), and “ABS ELEV DIFF” refers to the absolute value of this difference. NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988]

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

WY–MB501

41.19046

–106.11896

41.19047

–106.11896

2460.88

2460.79

0.09

WY–MB502

41.19209

–106.09834

41.19209

–106.09833

2429.51

2429.49

0.02

WY–MB503

41.18895

–106.08313

41.18895

–106.08313

2437.69

2437.67

0.02

WY–MB504

41.17132

–106.06800

41.17133

–106.06801

2500.66

2500.68

–0.02

0.02

WY–MB505

41.16023

–106.05934

41.16023

–106.05934

2472.42

2472.48

–0.06

0.06

WY–MB506

41.15066

–106.05078

41.15065

–106.05078

2442.59

2442.57

0.02

WY–MB507

41.12864

–106.00738

41.12862

–106.00738

2275.38

2275.50

–0.12

0.12

WY–MB508

41.14603

–105.97609

41.14602

–105.97608

2262.97

2263.02

–0.05

0.05

WY–MB509

41.15448

–105.96188

41.15447

–105.96188

2258.65

2258.61

0.03

WY–MB510

41.17454

–105.96686

41.17453

–105.96686

2247.40

2247.43

–0.03

0.03

WY–MB511

41.18156

–105.98720

41.18155

–105.98720

2282.29

2282.41

–0.12

0.12

WY–MB512

41.20351

–106.08888

41.20350

–106.08889

2410.12

2410.13

–0.02

0.02

WY–MB513

41.21824

–106.08941

41.21823

–106.08941

2391.92

2391.99

–0.07

0.07

WY–MB514

41.15853

–106.14494

41.15853

–106.14494

2795.83

2795.68

0.15

WY–MB515

41.14441

–106.16480

41.14441

–106.16481

2779.63

2779.50

0.13

WY–MB516

41.13696

–106.17559

41.13695

–106.17559

2758.67

2758.61

0.06

WY–MB517

41.14246

–106.32488

41.14245

–106.32489

2753.32

2753.25

0.07

WY–MB518

41.13765

–106.28225

41.13764

–106.28225

2858.08

2857.98

0.09

WY–MB519

41.12641

–106.30779

41.12640

–106.30779

2750.82

2750.57

0.25

WY–MB520

41.23346

–106.08523

41.23346

–106.08524

2390.43

2390.38

0.06

WY–MB521

41.25531

–106.07788

41.25530

–106.07789

2398.72

2398.82

–0.10

0.10

WY–MB522

41.26883

–106.07623

41.26882

–106.07624

2377.67

2377.53

0.14

WY–MB523

41.37340

–106.14062

41.37340

–106.14062

2992.11

2991.83

0.28

WY–MB524

41.38964

–106.13893

41.38964

–106.13892

3011.35

3011.26

0.09

WY–MB525

41.39842

–106.15353

41.39843

–106.15353

3011.69

3011.50

0.19

WY–MB526

41.40553

–106.13729

41.40554

–106.13730

2993.47

2993.19

0.28

WY–MB527

41.42013

–106.13554

41.42014

–106.13554

2948.85

2948.73

0.13

WY–MB528

41.43273

–106.14276

41.43274

–106.14277

2951.91

2951.76

0.16

Tables 3–7 21

UC LAT (NAD 83)

Gravity station

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

WY–MB529

41.44584

–106.12669

41.44585

–106.12670

2859.09

2858.94

0.15

WY–MB530

41.45834

–106.13831

41.45835

–106.13831

2819.46

2819.35

0.11

WY–MB531

41.46409

–106.12843

41.46408

–106.12843

2728.25

2726.51

1.74

WY–MB532

41.47037

–106.13498

41.47037

–106.13499

2712.18

2711.95

0.22

WY–MB533

41.44986

–106.14798

41.44985

–106.14799

3003.16

3002.90

0.26

WY–MB534

41.46325

–106.16424

41.46323

–106.16423

3002.84

3000.83

2.01

WY–MB535

41.35344

–106.14914

41.35343

–106.14915

3004.88

3004.53

0.36

WY–MB536

41.34814

–106.13838

41.34813

–106.13839

2988.23

2988.12

0.11

WY–MB537

41.34938

–106.12493

41.34936

–106.12494

2934.99

2935.39

–0.39

0.39

WY–MB538

41.36627

–106.15873

41.36628

–106.15873

2911.80

2911.48

0.33

WY–MB539

41.35579

–106.16766

41.35579

–106.16765

2783.06

2782.97

0.09

WY–MB540

41.34026

–106.16665

41.34026

–106.16665

2715.32

2715.31

0.01

WY–MB541

41.32412

–106.15787

41.32412

–106.15788

2591.96

2591.90

0.06

WY–MB542

41.28275

–106.10119

41.28275

–106.10119

2398.06

2398.07

–0.01

0.01

WY–MB543

41.22071

–106.07606

41.22071

–106.07605

2424.21

2424.16

0.04

WY–MB544

41.29736

–106.09520

41.29734

–106.09519

2421.13

2421.07

0.06

WY–MB545

41.31386

–106.13360

41.31385

–106.13360

2503.76

0.00

WY–MB546

41.30799

–106.19738

41.30798

–106.19738

2918.25

2918.09

0.16

WY–MB547

41.30010

–106.21714

41.30009

–106.21715

3031.58

3031.27

0.31

WY–MB548

41.30087

–106.23800

41.30087

–106.23801

3051.26

3050.86

0.40

WY–MB549

41.31434

–106.25226

41.31435

–106.25228

3175.54

3175.29

0.26

WY–MB550

41.29642

–106.25626

41.29643

–106.25626

3037.98

3037.74

0.24

WY–MB551

41.29071

–106.27609

41.29071

–106.27609

3074.98

3074.79

0.18

WY–MB552

41.28869

–106.23471

41.28869

–106.23470

2960.95

2960.86

0.09

WY–MB553

41.36680

–106.17763

41.36680

–106.17764

2863.04

2862.91

0.13

WY–MB554

41.37821

–106.18809

41.37821

–106.18811

2961.79

2961.66

0.13

WY–MB555

41.39324

–106.19073

41.39322

–106.19074

3036.08

3035.80

0.28

WY–MB556

41.40661

–106.19289

41.40661

–106.19292

3071.54

3071.25

0.29

Gravity station

22 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Table 5. Location information for the 139 gravity stations located on the Medicine Bow Mountains of Wyoming (WY–MB) from Brown and others (2025).—Continued

Table 5. Location information for the 139 gravity stations located on the Medicine Bow Mountains of Wyoming (WY–MB) from Brown and others (2025).—Continued [“Gravity station” refers to a unique identifier that is based on the station number used in the data source for this table. “UC LAT” and “UC LON” refer to the horizontal coordinates before differential correction. “DC LAT” and “DC LON” refer to the differentially corrected horizontal coordinates. “DGNSS ELEV” refers to the elevation data from the differential global navigation satellite system (dGNSS) equipment from the differentially corrected coordinates. “LIDAR ELEV” refers to the light detection and ranging (lidar) derived elevation from the 1-meter (m) digital elevation model (DEM). “ELEV DIFF” refers to the elevation difference (dGNSS – lidar), and “ABS ELEV DIFF” refers to the absolute value of this difference. NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988]

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

WY–MB557

41.41760

–106.20245

41.41760

–106.20246

3053.63

3053.41

0.22

WY–MB558

41.43099

–106.19507

41.43097

–106.19507

2995.17

2994.94

0.23

WY–MB559

41.44403

–106.20143

41.44402

–106.20143

2984.57

2984.45

0.12

WY–MB560

41.45465

–106.21267

41.45464

–106.21267

2990.60

2990.29

0.31

WY–MB561

41.47833

–106.20236

41.47833

–106.20237

2948.91

2948.56

0.35

WY–MB562

41.46460

–106.21658

41.46458

–106.21659

2981.29

2980.69

0.60

WY–MB563

41.45965

–106.23325

41.45964

–106.23326

2973.63

2972.78

0.84

WY–MB564

41.47559

–106.23098

41.47558

–106.23098

3071.38

3071.14

0.24

WY–MB565

41.48384

–106.21930

41.48382

–106.21931

3006.00

3005.99

0.01

WY–MB566

41.46829

–106.24426

41.46830

–106.24427

3078.87

3078.57

0.30

WY–MB567

41.46409

–106.25900

41.46410

–106.25901

3077.83

3077.51

0.32

WY–MB568

41.45625

–106.27278

41.45626

–106.27279

3073.55

3073.28

0.28

WY–MB569

41.47083

–106.28379

41.47083

–106.28379

3055.43

3055.10

0.33

WY–MB570

41.48219

–106.29583

41.48219

–106.29583

3035.92

3035.62

0.30

WY–MB571

41.48175

–106.26286

41.48175

–106.26286

3049.84

3049.53

0.31

WY–MB572

41.48593

–106.27830

41.48593

–106.27829

2946.91

2943.84

3.07

WY–MB573

41.49861

–106.28389

41.49859

–106.28388

2940.61

2940.15

0.46

WY–MB574

41.35981

–106.18889

41.35980

–106.18890

2905.54

2905.28

0.26

WY–MB575

41.37285

–106.20701

41.37284

–106.20703

3062.39

3062.32

0.06

WY–MB576

41.34232

–106.18478

41.34233

–106.18479

2782.28

2782.24

0.04

WY–MB577

41.32670

–106.18456

41.32671

–106.18457

2715.24

2715.07

0.17

WY–MB578

41.34118

–106.20559

41.34119

–106.20560

2889.53

2889.33

0.19

WY–MB579

41.34941

–106.21585

41.34942

–106.21586

2987.38

2987.24

0.14

WY–MB580

41.37390

–106.24701

41.37391

–106.24702

3225.84

3225.55

0.28

WY–MB581

41.35780

–106.23310

41.35781

–106.23311

3095.83

3095.61

0.21

WY–MB582

41.35124

–106.25958

41.35124

–106.25958

3194.78

3194.64

0.15

WY–MB583

41.35149

–106.28097

41.35150

–106.28097

3232.63

3232.42

0.21

WY–MB584

41.36052

–106.26446

41.36051

–106.26446

3218.29

3218.16

0.14

Tables 3–7 23

UC LAT (NAD 83)

Gravity station

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

WY–MB585

41.35868

–106.29448

41.35868

–106.29448

3284.27

3283.91

0.36

WY–MB586

41.34155

–106.30579

41.34154

–106.30579

3297.49

3297.19

0.30

WY–MB587

41.33727

–106.32016

41.33726

–106.32014

3217.13

3216.98

0.15

WY–MB588

41.31288

–106.35900

41.31287

–106.35901

3193.29

3193.05

0.24

WY–MB589

41.32837

–106.36387

41.32837

–106.36388

3101.15

3100.74

0.40

WY–MB590

41.31746

–106.34631

41.31745

–106.34631

3237.34

3237.02

0.32

WY–MB591

41.34466

–106.37755

41.34466

–106.37756

2967.09

2966.92

0.17

WY–MB592

41.36871

–106.37738

41.36872

–106.37738

3165.50

3165.29

0.21

WY–MB593

41.35236

–106.38354

41.35238

–106.38354

3051.39

3051.08

0.31

WY–MB594

41.35572

–106.39594

41.35571

–106.39594

3062.38

3062.04

0.35

WY–MB595

41.34407

–106.39819

41.34405

–106.39819

2891.16

2890.84

0.32

WY–MB596

41.33876

–106.41694

41.33875

–106.41695

2813.67

2813.49

0.18

WY–MB597

41.33429

–106.43329

41.33428

–106.43327

2760.35

2759.99

0.37

WY–MB598

41.33547

–106.44952

41.33545

–106.44952

2710.88

2710.85

0.03

WY–MB599

41.33790

–106.46655

41.33789

–106.46655

2655.43

2655.29

0.14

WY–MB600

41.33987

–106.48643

41.33986

–106.48643

2594.88

2593.65

1.23

WY–MB601

41.34448

–106.50441

41.34447

–106.50442

2532.86

2532.66

0.20

WY–MB602

41.34786

–106.52291

41.34786

–106.52291

2473.84

2473.60

0.24

WY–MB603

41.33354

–106.51849

41.33353

–106.51850

2501.09

2500.91

0.18

WY–MB604

41.32386

–106.50193

41.32386

–106.50194

2542.62

2542.48

0.13

WY–MB605

41.32934

–106.47678

41.32934

–106.47679

2651.04

2651.03

0.01

WY–MB606

41.32362

–106.45199

41.32361

–106.45200

2795.31

2795.19

0.11

WY–MB607

41.32444

–106.42427

41.32445

–106.42427

2924.09

2923.92

0.17

WY–MB608

41.34529

–106.36044

41.34529

–106.36044

3139.11

3138.94

0.17

WY–MB609

41.32228

–106.38720

41.32226

–106.38721

3002.52

3002.33

0.20

WY–MB610

41.32165

–106.40788

41.32164

–106.40789

2963.94

2963.83

0.12

WY–MB611

41.30854

–106.38885

41.30853

–106.38886

3091.15

3090.82

0.33

WY–MB612

41.29757

–106.38299

41.29756

–106.38301

3145.04

3144.82

0.23

Gravity station

24 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Table 5. Location information for the 139 gravity stations located on the Medicine Bow Mountains of Wyoming (WY–MB) from Brown and others (2025).—Continued

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

WY–MB613

41.28690

–106.37650

41.28688

–106.37651

3101.85

3101.70

0.15

WY–MB614

41.28625

–106.36023

41.28622

–106.36024

3000.34

3000.32

0.02

WY–MB615

41.29944

–106.35908

41.29941

–106.35908

3041.05

3040.98

0.07

WY–MB616

41.31065

–106.43329

41.31064

–106.43329

2844.89

2844.62

0.27

WY–MB617

41.30018

–106.44522

41.30019

–106.44522

2758.25

2757.99

0.26

WY–MB618

41.28856

–106.45303

41.28856

–106.45302

2683.76

2683.56

0.20

WY–MB619

41.27598

–106.45759

41.27598

–106.45759

2639.70

2639.35

0.36

WY–MB620

41.26670

–106.46745

41.26671

–106.46746

2645.14

2645.02

0.12

WY–MB621

41.26679

–106.44476

41.26681

–106.44476

2736.19

2735.88

0.31

WY–MB622

41.27006

–106.43131

41.27006

–106.43133

2882.87

2882.68

0.19

WY–MB623

41.27354

–106.41756

41.27355

–106.41759

2952.08

2951.80

0.28

WY–MB624

41.27963

–106.40188

41.27964

–106.40189

3063.82

3063.56

0.26

WY–MB625

41.28087

–106.39031

41.28089

–106.39033

2996.80

2996.54

0.27

WY–MB626

41.26106

–106.45549

41.26107

–106.45551

2661.72

2661.57

0.14

WY–MB627

41.24914

–106.46006

41.24914

–106.46008

2630.29

2630.16

0.13

WY–MB628

41.25510

–106.44214

41.25509

–106.44216

2607.63

2607.44

0.19

WY–MB629

41.25491

–106.42496

41.25491

–106.42498

2589.58

2589.53

0.05

WY–MB630

41.26188

–106.40894

41.26187

–106.40896

2607.66

2607.64

0.02

WY–MB631

41.26583

–106.39063

41.26583

–106.39064

2630.06

2630.01

0.05

WY–MB632

41.27255

–106.37663

41.27255

–106.37665

2654.22

2654.14

0.08

WY–MB633

41.27468

–106.35713

41.27467

–106.35714

2709.69

2709.54

0.15

WY–MB634

41.28110

–106.34158

41.28111

–106.34158

2786.58

2786.38

0.20

WY–MB635

41.28853

–106.32510

41.28853

–106.32510

2869.34

2869.14

0.20

WY–MB636

41.29911

–106.31249

41.29912

–106.31250

2944.56

2944.28

0.28

WY–MB637

41.28596

–106.47379

41.28599

–106.47380

2667.80

2667.65

0.15

WY–MB638

41.29813

–106.46541

41.29815

–106.46541

2713.53

2712.81

0.72

WY–MB639

41.30993

–106.45597

41.30994

–106.45597

2781.09

2780.78

0.31

Tables 3–7 25

UC LAT (NAD 83)

Gravity station

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

CO–WM300

38.31006

–105.35527

38.31004

–105.35526

2101.07

2100.79

0.28

CO–WM301

38.29837

–105.35721

38.29836

–105.35720

2121.65

2121.24

0.41

CO–WM302

38.29417

–105.35912

38.29414

–105.35911

2129.39

2129.27

0.12

CO–WM303

38.28391

–105.35495

38.28388

–105.35494

2148.09

2147.80

0.29

CO–WM304

38.27815

–105.35453

38.27814

–105.35454

2161.73

2161.46

0.27

CO–WM305

38.26982

–105.35141

38.26981

–105.35141

2179.96

2179.67

0.29

CO–WM306

38.26719

–105.35480

38.26718

–105.35478

2190.84

2190.52

0.31

CO–WM307

38.26307

–105.35934

38.26307

–105.35934

2201.92

2201.58

0.34

CO–WM308

38.26102

–105.36307

38.26101

–105.36307

2205.89

2205.52

0.37

CO–WM309

38.25873

–105.37197

38.25871

–105.37198

2216.51

2216.19

0.32

CO–WM310

38.25520

–105.37646

38.25519

–105.37647

2225.66

2225.29

0.37

CO–WM311

38.24934

–105.38073

38.24933

–105.38074

2234.73

2235.09

–0.36

0.36

CO–WM312

38.24533

–105.38533

38.24530

–105.38534

2243.33

2243.24

0.09

CO–WM313

38.23901

–105.38846

38.23899

–105.38848

2251.57

2251.65

–0.08

0.08

CO–WM314

38.23475

–105.38846

38.23472

–105.38848

2255.81

2255.86

–0.05

0.05

CO–WM315

38.23029

–105.39197

38.23027

–105.39198

2268.27

2268.04

0.23

CO–WM316

38.22717

–105.39525

38.22715

–105.39526

2274.55

2274.18

0.37

CO–WM317

38.22334

–105.40223

38.22333

–105.40227

2283.91

2284.06

–0.15

0.15

CO–WM318

38.23332

–105.40288

38.23332

–105.40289

2408.71

2408.94

–0.23

0.23

CO–WM319

38.24616

–105.39248

38.24616

–105.39249

2265.00

2264.96

0.04

CO–WM320

38.25602

–105.38334

38.25603

–105.38334

2280.00

2279.92

0.08

CO–WM321

38.25907

–105.39394

38.25907

–105.39394

2395.34

2395.25

0.09

CO–WM322

38.26950

–105.38806

38.26949

–105.38806

2398.60

2398.58

0.02

CO–WM323

38.27286

–105.39011

38.27285

–105.39010

2366.05

2366.03

0.02

CO–WM324

38.28735

–105.40667

38.28734

–105.40668

2274.35

2274.34

0.01

CO–WM325

38.29275

–105.39243

38.29273

–105.39243

2380.41

0.00

CO–WM326

38.28718

–105.38645

38.28716

–105.38644

2326.71

2326.70

0.01

CO–WM327

38.28938

–105.37284

38.28937

–105.37284

2224.21

2224.36

–0.15

0.15

Gravity station

26 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Table 6. Location information for the 59 gravity stations located on the Wet Mountains of Colorado (CO–WM) from Magnin and Anderson (2024).

Table 6. Location information for the 59 gravity stations located on the Wet Mountains of Colorado (CO–WM) from Magnin and Anderson (2024).—Continued [“Gravity station” refers to a unique identifier that is based on the station number used in the data source for this table. “UC LAT” and “UC LON” refer to the horizontal coordinates before differential correction. “DC LAT” and “DC LON” refer to the differentially corrected horizontal coordinates. “DGNSS ELEV” refers to the elevation data from the differential global navigation satellite system (dGNSS) equipment from the differentially corrected coordinates. “LIDAR ELEV” refers to the light detection and ranging (lidar) derived elevation from the 1-meter (m) digital elevation model (DEM). “ELEV DIFF” refers to the elevation difference (dGNSS – lidar), and “ABS ELEV DIFF” refers to the absolute value of this difference. NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988]

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

CO–WM328

38.26465

–105.37548

38.26464

–105.37548

2345.54

2345.57

–0.03

0.03

CO–WM329

38.25471

–105.36188

38.25469

–105.36189

2257.82

2257.71

0.11

CO–WM330

38.24246

–105.37071

38.24243

–105.37072

2302.59

2302.50

0.09

CO–WM331

38.24149

–105.37685

38.24148

–105.37686

2271.77

2271.80

–0.03

0.03

CO–WM332

38.11421

–105.18721

38.11420

–105.18722

2861.52

2861.53

–0.01

0.01

CO–WM333

38.11834

–105.19500

38.11833

–105.19501

2844.62

0.00

CO–WM334

38.11539

–105.20536

38.11538

–105.20537

2851.18

2851.05

0.13

CO–WM335

38.09331

–105.21065

38.09329

–105.21067

3263.29

3262.77

0.52

CO–WM336

38.09336

–105.17546

38.09335

–105.17546

2882.04

2881.89

0.15

CO–WM337

38.09126

–105.17045

38.09125

–105.17046

2955.79

2956.01

–0.22

0.22

CO–WM338

38.08223

–105.15881

38.08223

–105.15881

3160.31

3160.21

0.10

CO–WM339

38.07603

–105.16797

38.07602

–105.16798

3161.92

3161.82

0.10

CO–WM340

38.07120

–105.17146

38.07119

–105.17146

3105.18

3105.85

–0.67

0.67

CO–WM341

38.06252

–105.18589

38.06251

–105.18590

3159.78

3159.74

0.04

CO–WM342

38.07947

–105.18030

38.07944

–105.18029

2925.35

2921.68

3.67

CO–WM343

38.09203

–105.14929

38.09200

–105.14930

2941.98

2941.82

0.16

CO–WM344

38.08606

–105.13990

38.08604

–105.13992

2934.02

2934.11

–0.09

0.09

CO–WM345

38.06968

–105.22355

38.06966

–105.22357

3171.49

3171.41

0.08

CO–WM346

38.07352

–105.22973

38.07349

–105.22974

3189.36

3189.64

–0.28

0.28

CO–WM347

38.07574

–105.24332

38.07573

–105.24332

3115.80

3115.97

–0.17

0.17

CO–WM348

38.06952

–105.23591

38.06952

–105.23593

3068.66

3068.71

–0.05

0.05

CO–WM349

38.06894

–105.22953

38.06894

–105.22955

3119.76

3119.79

–0.03

0.03

CO–WM350

38.07174

–105.23154

38.07174

–105.23155

3142.02

3141.75

0.27

CO–WM351

38.08607

–105.24776

38.08608

–105.24777

3170.15

3169.97

0.18

CO–WM352

38.08224

–105.24561

38.08225

–105.24560

3140.92

3140.93

–0.01

0.01

CO–WM353

38.08720

–105.22464

38.08718

–105.22464

3220.52

3220.55

–0.03

0.03

CO–WM354

38.09102

–105.22718

38.09100

–105.22718

3260.35

3260.33

0.02

CO–WM355

38.09067

–105.23085

38.09065

–105.23085

3287.47

3288.41

–0.94

0.94

Tables 3–7 27

UC LAT (NAD 83)

Gravity station

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

CO–WM356

38.08886

–105.23514

38.08884

–105.23515

3280.50

3280.75

–0.25

0.25

CO–WM357

38.08606

–105.23944

38.08604

–105.23944

3224.57

3224.24

0.33

CO–WM358

38.09156

–105.23900

38.09156

–105.23900

3313.85

3313.63

0.22

Gravity station

28 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Table 6. Location information for the 59 gravity stations located on the Wet Mountains of Colorado (CO–WM) from Magnin and Anderson (2024).—Continued

Table 7. Location information for the 56 gravity stations located on the Keweenaw Peninsula of Michigan (MI–KP0) from Murchek and others (2025). [“Gravity station” refers to a unique identifier that is based on the station number used in the data source for this table. “UC LAT” and “UC LON” refer to the horizontal coordinates before differential correction. “DC LAT” and “DC LON” refer to the differentially corrected horizontal coordinates. “DGNSS ELEV” refers to the elevation data from the differential global navigation satellite system (dGNSS) equipment from the differentially corrected coordinates. “LIDAR ELEV” refers to the light detection and ranging (lidar) derived elevation from the 1-meter (m) digital elevation model (DEM). “ELEV DIFF” refers to the elevation difference (dGNSS – lidar), and “ABS ELEV DIFF” refers to the absolute value of this difference. NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988]

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

MI–KP0–1

47.19247

–88.48937

47.19248

–88.48937

357.97

357.83

0.14

MI–KP0–2

47.2386

–88.61182

47.2386

–88.61181

186.12

185.82

0.31

MI–KP0–3

47.23998

–88.59468

47.23998

–88.59468

189.02

188.48

0.53

MI–KP0–4

47.22843

–88.59448

47.22843

–88.59447

198.65

198.31

0.34

MI–KP0–5

47.23928

–88.59002

47.23927

–88.59001

194.57

194.42

0.15

MI–KP0–6

47.22849

–88.58479

47.22849

–88.58478

207.38

206.85

0.52

MI–KP0–7

47.22858

–88.57424

47.22857

–88.57423

221.14

220.83

0.31

MI–KP0–8

47.23942

–88.57388

47.23942

–88.57387

193.96

193.64

0.32

MI–KP0–9

47.21424

–88.56344

47.21424

–88.56344

283.33

283.08

0.24

MI–KP0–10

47.18516

–88.56329

47.18514

–88.56329

318.8

318.72

0.07

MI–KP0–11

47.21431

–88.55265

47.21431

–88.55265

300.8

300.71

0.09

MI–KP0–12

47.2138

–88.54236

47.21379

–88.54235

323.6

323.45

0.15

MI–KP0–13

47.18488

–88.53965

47.18487

–88.53965

333.12

333.07

0.05

MI–KP0–14

47.21352

–88.53145

47.21351

–88.53145

327.83

327.78

0.05

MI–KP0–15

47.2067

–88.52091

47.2067

–88.52091

351.73

351.52

0.21

MI–KP0–16

47.21363

–88.52081

47.21362

–88.52080

351.01

350.86

0.14

MI–KP0–17

47.17455

–88.51855

47.17455

–88.51855

333.56

333.58

–0.02

0.02

MI–KP0–18

47.20738

–88.50895

47.20738

–88.50894

360.93

360.62

0.3

MI–KP0–19

47.19935

–88.49976

47.19935

–88.49976

359.46

359.34

0.12

MI–KP0–20

47.19036

–88.49965

47.19035

–88.49964

353.43

353.33

0.11

MI–KP0–21

47.19392

–88.49585

47.19391

–88.49584

356.93

356.81

0.13

MI–KP0–22

47.18917

–88.49367

47.18916

–88.49366

357.74

357.75

–0.01

0.01

MI–KP0–23

47.13179

–88.48612

47.13179

–88.48611

190.49

190.48

0.01

MI–KP0–24

47.18894

–88.48568

47.18893

–88.48569

365.34

365.31

0.03

MI–KP0–25

47.19946

–88.48134

47.19945

–88.48133

359.63

359.64

–0.01

0.01

MI–KP0–26

47.18842

–88.47950

47.18843

–88.47950

354.53

354.47

0.06

MI–KP0–27

47.14506

–88.47867

47.14505

–88.47866

269.47

269.54

–0.07

0.07

MI–KP0–28

47.1853

–88.47486

47.1853

–88.47485

354.27

354.18

0.09

Tables 3–7 29

UC LAT (NAD 83)

Gravity station

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

MI–KP0–29

47.18223

–88.47155

47.18223

–88.47155

337.38

337.18

0.2

MI–KP0–30

47.20707

–88.47135

47.20707

–88.47134

365.23

365.08

0.16

MI–KP0–31

47.17804

–88.46743

47.17804

–88.46742

324.81

324.66

0.15

MI–KP0–32

47.17419

–88.46209

47.17417

–88.46208

314.46

313.5

0.96

MI–KP0–33

47.14882

–88.45806

47.14882

–88.45805

190.87

190.83

0.04

MI–KP0–34

47.1709

–88.45737

47.1709

–88.45735

306.2

305.98

0.23

MI–KP0–35

47.1674

–88.45202

47.16739

–88.45201

273.23

273.09

0.14

MI–KP0–36

47.20788

–88.44713

47.20787

–88.44713

356.72

356.54

0.18

MI–KP0–37

47.18497

–88.44653

47.18497

–88.44652

311.7

311.74

–0.04

0.04

MI–KP0–38

47.19592

–88.44639

47.19592

–88.44638

337

337.07

–0.07

0.07

MI–KP0–39

47.16467

–88.44616

47.16467

–88.44616

226.5

226.36

0.14

MI–KP0–40

47.17307

–88.44471

47.17307

–88.44472

267.49

267.5

–0.02

0.02

MI–KP0–41

47.16355

–88.43915

47.16355

–88.43915

187.27

187.07

0.2

MI–KP0–42

47.16107

–88.43507

47.16106

–88.43507

184.11

184.01

0.09

MI–KP0–43

47.15894

–88.43253

47.15893

–88.43253

184.07

183.39

0.68

MI–KP0–44

47.15447

–88.42535

47.15447

–88.42535

198.16

197.89

0.27

MI–KP0–45

47.14855

–88.42529

47.14855

–88.42530

216.99

214.63

2.36

MI–KP0–46

47.14989

–88.41428

47.14988

–88.41427

185.32

185.14

0.18

MI–KP0–47

47.14911

–88.39405

47.14911

–88.39405

196.15

195.98

0.17

MI–KP0–48

47.17075

–88.38358

47.17075

–88.38358

226.35

226.3

0.05

MI–KP0–49

47.14186

–88.38341

47.14186

–88.38341

218.89

218.71

0.19

MI–KP0–50

47.12744

–88.36215

47.12744

–88.36215

221.22

221

0.22

MI–KP0–51

47.11808

–88.34597

47.11808

–88.34597

202.97

202.92

0.05

MI–KP0–52

47.1147

–88.34358

47.11471

–88.34357

195.46

194.97

0.49

MI–KP0–53

47.17086

–88.34093

47.17086

–88.34092

226.63

226.62

0.01

30 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

Table 7. Location information for the 56 gravity stations located on the Keweenaw Peninsula of Michigan (MI–KP0) from Murchek and others (2025).—Continued

Table 7. Location information for the 56 gravity stations located on the Keweenaw Peninsula of Michigan (MI–KP0) from Murchek and others (2025).—Continued [“Gravity station” refers to a unique identifier that is based on the station number used in the data source for this table. “UC LAT” and “UC LON” refer to the horizontal coordinates before differential correction. “DC LAT” and “DC LON” refer to the differentially corrected horizontal coordinates. “DGNSS ELEV” refers to the elevation data from the differential global navigation satellite system (dGNSS) equipment from the differentially corrected coordinates. “LIDAR ELEV” refers to the light detection and ranging (lidar) derived elevation from the 1-meter (m) digital elevation model (DEM). “ELEV DIFF” refers to the elevation difference (dGNSS – lidar), and “ABS ELEV DIFF” refers to the absolute value of this difference. NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988]

Gravity station

UC LAT (NAD 83)

UC LON (NAD 83)

DC LAT (NAD 83)

DC LON (NAD 83)

DGNSS ELEV (m) (NAVD 88)

LIDAR ELEV (m) (NAVD 88)

ELEV DIFF (m)

ABS ELEV DIFF (m)

MI–KP0–54

47.13504

–88.29974

47.13504

–88.29974

192.78

192.76

0.02

MI–KP0–55

47.12553

–88.29006

47.12553

–88.29006

189.78

187.11

2.67

1MI–KP0–M65

47.2436

–88.44747

47.2436

–88.44747

380.18

379.69

0.49

1The data for this National Geodetic Survey (NGS) station are from NGS (2025). This gravity station identifier was created for use in this report.

Tables 3–7 31

32 The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

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Murchek and others—The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction—OFR 2025–1019, ver. 1.1.

ISSN 2331-1258 (online) https://doi.org/10.3133/ofr20251019

The Feasibility of Using Lidar-Derived Digital Elevation Models for Gravity Data Reduction

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