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Map coordinates to GPS
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Frank Perkins
(fperkins)

Locale: North East
Map coordinates to GPS on 01/24/2008 08:49:13 MST Print View

I have a map of an area I plan to hike. On the map are "coordinates"? of 4660000N on the right hand side [latitude?] and up top 624000E for longitude?

I then pull up Google Earth and I'm trying to map the location I see in the map to Google Earth. I thought the best way would be to convert the coordinates to GPS and just enter them into the Google Earth search. My question is I'm not sure how the map measurements relate back to a GPS point. Can someone explain and point me to the "idiots guide" to doing this?

Thanks

Mike W
(skopeo) - F

Locale: British Columbia
Map coordinates to GPS on 01/24/2008 12:48:56 MST Print View

Your GPS is set to display UTM coords (a map projection). You can just go into setup in your GPS and changes the coordinate reference to Geographic and the coordinates will match google earth.

If you have a Garmin GPS and you have Mapsource and Google Earth both installed on your computer you can load your waypoints and tracks into Mapsource directly from your GPS and view them directly in Google earth (under the view menu in Mapsource, pick "View in Google Earth").

Frank Perkins
(fperkins)

Locale: North East
Re: Map coordinates to GPS on 01/24/2008 13:37:49 MST Print View

Sorry if I wasn't clear but I don't actually own a GPS. What I'm trying to do is find coordinates on my physical paper map in Google Earth.

Edited by fperkins on 01/24/2008 13:38:20 MST.

Mike W
(skopeo) - F

Locale: British Columbia
Map coordinates to GPS on 01/24/2008 14:12:18 MST Print View

There's a tool called Geocalc (freebee... google for it) that can do coordinate transformations for you. You still have to convert your coords from UTM to Geographics and Geocalc will do that. It's a bit picky with input formats but it works really well. I'm not a Google Earth expert so I don't know if you can just change your coordinate input preference to UTM and let Google Earth do the transform.

Neil Bender
(nebender) - F
Re: Re: Map coordinates to GPS on 01/24/2008 14:18:29 MST Print View

Your map appears to have UTM coordinates listed. Those numbers are meters, so if your map has a kilometer scale you can measure your own 1 km gridlines using that scale to estimate coordinates of points on the map. UTM also has zones associated with it, which you will also need. The other thing that effects accuracy is reference datums, usually either NAD27, or WGS84 or such. These datums have different reference points. If you don't know which one your map or Google uses you could be off by something like 30 meters.

These pages might help:

http://www.maptools.com/UsingUTM/

http://www.uwgb.edu/DutchS/UsefulData/UTMFormulas.HTM

http://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system

Frank Perkins
(fperkins)

Locale: North East
Re: Map coordinates to GPS on 01/24/2008 15:07:14 MST Print View

Thanks for the help everyone. Knowing that the numbers on the map refer to UTM sure does it make it easier ;-) Now I know what the UTM overlays in the BPL store are used for!

In Google Earth's preferences, you can change the lat/long to UTM. Now I need an overlay to really zoom and get an accurate point.