Fieldcraft Matching your GPS to your Map

[kraigWY]

The USGS Map Stores sell 1:24,000 maps for $8 each. They are 7.5 minute maps.

You can use your GPS Long/Lat set up but its much easier to use the UTM (Universal Transverse Mercator) Grid set up on your GPS instead of Long/lat.

Look at the top of the maps, you'll see the Easting and Northing 1000 meter grids every 1000 meters.

It will looks something like this: 3<span style="font-weight: bold">46</span>000<span style="font-weight: bold">E</span> on the top and 41<span style="font-weight: bold">64</span>000<span style="font-weight: bold">N</span> on the side.

When set on UTM your GPS will give the same readings.

Now you have (or should have) your compus with you also. Get one with the 1:24000 scale.

Or get a map scale/templet with a 1:24000 Scale.

The UTM will show on the map as 1000 sq meters. You're compass will break it down into 100 or 10 meters (depends on the compass).

I've found this more accurate and faster then trying to line up your Long/Lat on the map, even if you draw Long/Lat lines across the map.

This also makes it easier to use your map as a range finder.

Just a tad bit of information I pass out in my map reading/Land Nav classes.

 

[Wes_Mantooth]

Re: Matching your GPS to your Map

Anyone who uses this method will need to have plenty of 1000meter grid squares on hand. Let me know if you need some, I sell them <span style="font-style: italic"> very</span> cheap.

 

[kraigWY]

Re: Matching your GPS to your Map

No all you need is a map. You can do it with a BLM or NF map which are normally 1:100,000.

I just happen to like the 1:24000 and its better detail.

 

[Wes_Mantooth]

Re: Matching your GPS to your Map

Are you sure you were in the army?

 

[rmfield]

Re: Matching your GPS to your Map

Be sure to match the GPS datum to the map datum. In the case of most (maybe even all) USGS 7.5 minute quads the datum is NAD27. UTM is definately the way to go for land nav.

Edit: Here's a link to a nice simple explanation.