Spatzda ([info]phuphuphnik) wrote,
2005-07-27 03:05:00
  • Mood: sad
We were on vacation in Mn, and found some land. I just looked at some USGS data, and the GPS I was using is off by 300' After recalculating it turns out that the wonderful building site we were looking at is no where near the actual property.

  • Post a new comment

    Error

    Anonymous comments are disabled in this journal

    switch

    Your IP address will be recorded 

     
    Help
  • 3 comments

[info]gomeza

July 27 2005, 13:37:31 UTC 6 years ago

Holy cow - how?? What brand and model was it before you threw it in the trash? (so I won't buy one)

[info]phuphuphnik

July 28 2005, 04:24:30 UTC 6 years ago

Actually it is a Garmin GPS III, about 5 years old. The problem was that I had not calibrated it. I borrowed it, BTW. So, between that and a lousy map from the realitor, I was off by 300 feet. Not too bad for 17 acres, except that it was only 400' wide. poopies.

[info]whl

July 27 2005, 18:21:49 UTC 6 years ago

Was it because the map used one geoid, and the GPS receiver was set to use another? It's important to match them.


As the USGS says:


"Select the correct horizontal datum. Most GPS units default to a datum called the World Geodetic System of 1984 (WGS84). However, most USGS maps are referenced to a different datum, the North American Datum of 1927 (NAD27). A few USGS maps are set to the North American Datum of 1983 (NAD83), which is virtually identical to WGS84. Check the map information at the lower left corner of the USGS 7.5’ quadrangle to determine the correct datum used in the making of the map. Correct datum is especially important of you are using the UTM coordinate system. Your GPS setup menu may present several variations of NAD27 to select from; most users will select NAD27 CONUS, which is appropriate for the continental US."
Create an Account
Forgot your login or password?
Facebook Twitter More login options
English • Español • Deutsch • Русский…