Merging GPS

Technologies and

Geoscience

By Tom Morris, Computer Specialist,

National Science and Technology

Center, ST-333

Discussion

Global Positioning System

(GPS) technology is quickly

becoming an indispensable

tool in assisting the science

community in reporting

physical properties of surface

and sub-surface structures.

GPS receivers are very small

and easy-to-use. Some GPS

receivers have an internal

barometric pressure chip that

allows elevation data to be

collected with an accuracy of

1.5 feet. This level of accuracy permits the mapping of

surface elevation and subsurface change(s). An ArcView

extension is being created by

NSTC staff members Wendy

Bullock and Matt Brown

(ST-134) that will automate

the importation of the Sting.

DAT file in order to create a

“point feature” theme including the resistivity measurement

X, Y and Z points created in

UTM coordinate system. This

ArcView “Automated Import”

extension can be used with the

ArcView “3D-Analyst”

extension to create a threedimensional map. You can

also “peal” the layers off to

show extent of certain values

at depth. Contact Brent

Lewis at b1lewis@blm.gov or

Tom Morris at

tom_morris@blm.gov.

As you can see GPS can

document attributes related

to a geologic formation and

allow the reporting GIS software to calculate not only:

(1) distance and areal extent

of the formation; but also (2)

allow the geologist to “tie-in”

subsurface geophysical

surveys to produce a 3-D

visual. At the same time the

GPS-derived data will assist

you in preparing volume

calculations.

Figure 1. demonstrates

surface placements of electrodes, which will, through

NO. 51 DATE 04/18/01

Range

GIS and GPS

Figure 1. Using electricity to portray subsurface conditions.
use of electricity, portray

relative subsurface resistivity

results and their physical

relationship to the wetlands

that are being studied. Figure

2. is an example of a study of

an evaporation pond groundwater plume, which extends

to the Northwest.

Integration of the resistivity

survey lines with the ArcView

software provides a map that

can depict the plume flow and

it’s geographic collocation to

a nearby residential area.

This integration can accurately assist the subject

specialist in their task of

providing for public safety.

The BLM’s National

Science and Technology

Center can provide the

agency Resource Administrator with expert geophysical and GIS documentation

of most surface and subsurface structures and targets.

This support saves the

subject specialist from

having to pursue costly and

time-intensive negotiated

contract processes.

Contact

Tom Morris

National Science and 

Technology Center, BLM

Denver Federal Center

Building 50, PO Box 25047

Denver, CO, 80225-0047

phone (303) 236-0964

fax (303) 236-3508

email tom_morris@blm.gov 

Range

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Bureau of Land Management personnel and some of their customers.

Information in this Resource Note is based on the opinion and

experience of the author and has not been peer-reviewed. Conclusions

and opinions expressed herein do not

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Figure 2. Integrating resistivity survey data and ArcView.