I tried creating a waypoint on my GPS unit from coordinates on a Topo Map from upstate NY. The best I can figure, the map had a grid marked in meters, but also had tick maks with numbers for Degrees. The grid was in 1 kilometer squares. The Degree ticks were only on the top and bottom and there were only a few of those. To get the most accurate coordinates, it wold be best to use the metric scale, but I was unsure of using the metric coords on the GPS unit. Any insite as the best way to input a waypoint from this type of map?

Thanks

 

Most likely your map and GPS are not using the same datum. I would suspect your GPS is set up by default for WGS-84, while it is common for maps to use NADA-27. An easy way to convert from one datum to another is with the help of this webpage Coordinate Translation Check the legend of your map it should tell you what datum is being used.

 

DaveNV,

Thanks for you're response. I did a little more checking and basically, the grid systems being used on the NY topo maps it is the UTM datum. The problem is, if someone gives me coordinate in Lat & Lon to a specific lamdmark, I didn't know how to accuratly locate it on the topo map.

I have since found that my GPS unit automatically translates the coodinates of my user landmarks back and forth between the two datums as I select betwee the two. So, if you give me a landmark in Lat & Lon, I can input that on the GPS using the L&L datum, switch over to the UTM datum, read the translated coordinates off the GPS locate it on the topo map using the UTM grid on it.

Simple [img]i/expressions/face-icon-small-smile.gif[/img]


Actually, I'm not sure if UTM vs L&L are datums or not. Can you clarify?

 

Arrowhead,
Check out this website How to Read Universal Transverse Mercator (UTM) Grid You'll find good information on UTM.

Dave

 

DaveNV,
Thank for the info. Just what I was looking for.