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Title: An evaluation of a portable GPS unit for geologic mapping. [Global Positioning System]

Abstract

A Magellan Nav 5000 GPS was used to evaluate the precision and accuracy of geographic fixes (latitude and longitude and elevation) obtainable as well as the advantages and disadvantages of its use in field situations. The precision of the fixes was investigated by making 10 determinations at the same location at about one minute intervals on four different occasions at different times of day. For each group of ten fixes the standard deviation was either .01 or .02 (.01 = 18.5 meters of latitude and 14 meters of longitude at 40 degrees of latitude). The accuracy of the fixes was investigated in two ways: first, by making ten separate determinations where the geographic coordinates are accurately known (a USGS bench mark) and, second, by recording all the determinations (38) shown over a continuous 15 minute period. In both cases the mean values agreed either exactly with the known coordinates or varied by .01 minute. The use of mean values from multiple determination is recommended for large scale mapping. A test of the assigned altitude on the precision of fixes indicates little or no apparent affect up to at least 400 feet of difference of elevation between the assigned value andmore » the actual elevation. This indicates that the use of an estimated elevation accurate within 400 feet will not affect precision of the fix. There are certain field situations where a portable GPS would have obvious utility: in remote areas where base maps are lacking or of too small a scale, where suitable base maps exist but geographical positioning is difficult because of a lack of mapped cultural or physical features. GPS is some what less useful where tree cover prevents good satellite reception and is not suitable for very large scale mapping where errors of 10 meters would be significant.« less

Authors:
 [1]
  1. Miami Univ. Oxford, OH (United States). Geology Dept.
Publication Date:
OSTI Identifier:
5936011
Report Number(s):
CONF-921058-
Journal ID: ISSN 0016-7592; CODEN: GAAPBC
Resource Type:
Conference
Journal Name:
Geological Society of America, Abstracts with Programs; (United States)
Additional Journal Information:
Journal Volume: 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; Journal ID: ISSN 0016-7592
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; GEODETIC SURVEYS; ACCURACY; MEASURING INSTRUMENTS; PERFORMANCE TESTING; COORDINATES; LEVELS; MAPPING; POSITIONING; TECHNOLOGY ASSESSMENT; GEOPHYSICAL SURVEYS; SURVEYS; TESTING; 580000* - Geosciences

Citation Formats

Scotford, D M. An evaluation of a portable GPS unit for geologic mapping. [Global Positioning System]. United States: N. p., 1992. Web.
Scotford, D M. An evaluation of a portable GPS unit for geologic mapping. [Global Positioning System]. United States.
Scotford, D M. 1992. "An evaluation of a portable GPS unit for geologic mapping. [Global Positioning System]". United States.
@article{osti_5936011,
title = {An evaluation of a portable GPS unit for geologic mapping. [Global Positioning System]},
author = {Scotford, D M},
abstractNote = {A Magellan Nav 5000 GPS was used to evaluate the precision and accuracy of geographic fixes (latitude and longitude and elevation) obtainable as well as the advantages and disadvantages of its use in field situations. The precision of the fixes was investigated by making 10 determinations at the same location at about one minute intervals on four different occasions at different times of day. For each group of ten fixes the standard deviation was either .01 or .02 (.01 = 18.5 meters of latitude and 14 meters of longitude at 40 degrees of latitude). The accuracy of the fixes was investigated in two ways: first, by making ten separate determinations where the geographic coordinates are accurately known (a USGS bench mark) and, second, by recording all the determinations (38) shown over a continuous 15 minute period. In both cases the mean values agreed either exactly with the known coordinates or varied by .01 minute. The use of mean values from multiple determination is recommended for large scale mapping. A test of the assigned altitude on the precision of fixes indicates little or no apparent affect up to at least 400 feet of difference of elevation between the assigned value and the actual elevation. This indicates that the use of an estimated elevation accurate within 400 feet will not affect precision of the fix. There are certain field situations where a portable GPS would have obvious utility: in remote areas where base maps are lacking or of too small a scale, where suitable base maps exist but geographical positioning is difficult because of a lack of mapped cultural or physical features. GPS is some what less useful where tree cover prevents good satellite reception and is not suitable for very large scale mapping where errors of 10 meters would be significant.},
doi = {},
url = {https://www.osti.gov/biblio/5936011}, journal = {Geological Society of America, Abstracts with Programs; (United States)},
issn = {0016-7592},
number = ,
volume = 24:7,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1992},
month = {Wed Jan 01 00:00:00 EST 1992}
}

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