into some of logical *vehicle* to make hunting more productive and interesting.

With the GPS and its electronic compass and a hunting area topo map what am I to use for plotting, bearings, "defaults"??? True, Magnetic, Grid???

Any recommended readings that bridge these information tools?

Thanks much...

Lion_dog

I dont fully understand the question.

You want to combine data ?

Are you trying to map a route on a hand help GPS unit ?

Sorry...

When, do you use Magnetic vs True North plotting bearings on a topo map? When in the field you are to use Magnetic north (declination correction), but if you plotting on a topo map AT home at you using Magnetic or True North bearings? Do you use True North at home THEN +/- the declination correction?

DeLorme sells GPS top maps.  It would just suck having to carry around a laptop with you.  I'm not sure of the portability of their topo maps to other handheld devices but I would check with them first.

[url]http://www.delorme.com/[/url]

terrain navigator from maptech will interface real time with your gps unit.  you should probably opt to get the version that will load onto a pda computer, which you will also have to buy.  on the other hand you could just trust the old compass and paper map!!!  and just plain hunting needs to be more interesting for you [:(]

Topographic maps (as well as most other charts used for navigation) are set with the North - South lines aligned with true North.

If you measure (on the map) the bearing of a course line as an angle from the true North grid line, the bearing will also be in reference to true North.

The magnetic course to follow on the ground will equal the true course corrected for magnetic variation (add West variation, subtract East variation).

Exampe:

True course (as measured on your map with a protractor) from A to B is 085 degrees true.

Magnetic variation is 5 West.

True Course + West Variation = Magnetic Course

To travel from point A to point B, you would use your compass to travel along a magnetic course of 090 to reach point B.

So to answer your question,  it would probably be better to set your GPS compass to Magnetic North so it will agree with your back up magnetic compass.  Just remember to subtract East Variation from your map bearing to get magnetic heading for the field.

Go here [url]http://www.softpedia.com/public/cat/10/18/10-18-41.shtml[/url]and download USAPhotoMaps 2.15



 The declination is marked on USGS quads.

Thanks all you gents... Waldo's link provides some incredible TOOLs to work with. Steve6 gave me clarity on my confusion with bearings. Rockhound, u-baddog, SWIRE - appreciate it all.

Part of what I wanted to do is take a land surveyor's blueprint with NO PIN setting (GPS Lat/Lon) for the baseline of UTM (Easting/Northing) to follow the bearings and outline the land. Since there is none, I can not MARK all the land our Hunting Club Leases so that we don't trespass. AND to MAP where all of our hunters are in relationship to each other. While attempting to be the "map wizard" I might have come across better INFO to locate deer and ...

Thanks again guys!