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- Feb 18, 2007
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- Haley
The conjugate graticule used for most current maps in the U. S. of A. is North American Datum 1983 (NAD83). USGS is converting many older maps to this datum.
Here is a site to convert back and forth among GPS and NAD83:
http://www.jeepreviews.com/wireless-gps-coordinates/
Here is a site to convert between NAD83 and the older NAD27: http://www.ngs.noaa.gov/cgi-bin/nadcon.prl
Keep in mind that more precise measuring techniques and geologic activities are constantly changing the earth. No system is totally accurate.
Whatever datum you use, you'll almost always be within 1/4 mile of your target. Remember that limit when you get to a location and no victim is found--you are very close, keep looking. Shouldn't be much trouble to find someone if they are on a road. If you are the victim, make sure you are visible. Sounds simple, but people have died after crawling into a crevice or log to escape the weather, and searchers walked within feet and never saw them.
Here is a site to convert back and forth among GPS and NAD83:
http://www.jeepreviews.com/wireless-gps-coordinates/
Here is a site to convert between NAD83 and the older NAD27: http://www.ngs.noaa.gov/cgi-bin/nadcon.prl
Keep in mind that more precise measuring techniques and geologic activities are constantly changing the earth. No system is totally accurate.
Whatever datum you use, you'll almost always be within 1/4 mile of your target. Remember that limit when you get to a location and no victim is found--you are very close, keep looking. Shouldn't be much trouble to find someone if they are on a road. If you are the victim, make sure you are visible. Sounds simple, but people have died after crawling into a crevice or log to escape the weather, and searchers walked within feet and never saw them.