True North

[chsr17]

I hope this is the right forum for this but I can't figure this out! I live in Alaska and most of the maps are NAD27 and not new. The magnetic declination at the time was 27e but the current NOAA declination now is 21e. Do I go with the declination from the old map or use the new one when using map and compass. I do have a GPS but I like having the compass and map as back up!

Thanks!

[+oldsoldier]

Your dec is gonna throw you off either way...the map is severely outdated, so even terrain association may not work. If YOU shoot an azimuth, then convert it, you would use the dec di on the map; however, again, it may not work so well. Your best bet would be to get a newer map. There are resources online for getting updated maps....beats being lost in the wilderness of alaska!

[NewMexicoOutdoor]

Well..using "dead reckoning" as waypointing with map & compass hasn't changed. If ur expaditious about taking a reading on the high spots.

 

Finding a landmark you recognize and coming up with a bearing ...then declination shouldn't come into play so much at all??!!??

 

Then moving to that general waypoint/landmark ..then making another waypoint/landmark. Dan

Edited February 18, 2009 by NewMexicoOutdoor

[+tec_64]

Use the new declination with your compass to align your map edge to true north.

 

As for the datum (NAD27) and your GPS: if you get coords in WGS84, switch your GPS to WGS84, enter your coords then switch your GPS datum to NAD27 for use with your maps.

 

Somebody correct me if I'm wrong.

 

tec_64