Surveyor Lat Lon and Marine Lat Lon

[pitch bait]

I have a hand held GPS. I took it into the woods and recorded some oak flats and different spots that I would like to hunt. I wanted to look at them on the Flash earth site. The numbers on the site and the gps numbers that I have dont match. Is ther different Lat Lon that they would use for land surveyors purposes? The numbers that should be the same spot are


39 06.276 These are from my GPS
7450.563

39 6' 6.8 These are from flashearth.com
74 50'32.0

Im confused.

[striper101]

I have a hand held GPS. I took it into the woods and recorded some oak flats and different spots that I would like to hunt. I wanted to look at them on the Flash earth site. The numbers on the site and the gps numbers that I have dont match. Is ther different Lat Lon that they would use for land surveyors purposes? The numbers that should be the same spot are


39 06.276 These are from my GPS
7450.563

39 6' 6.8 These are from flashearth.com
74 50'32.0

Im confused.

Bobby,
Have you tried Google Earth? I don't have it on this computer, but did have on my old one.

[pitch bait]

Bobby,
Have you tried Google Earth? I don't have it on this computer, but did have on my old one.

Do they give you GPS. In flashearth.com you can converth the map into like six or seven diferent maps in a second. The different maps sites ae listed on the side of the screen it is a really cool site.

[striper101]

Do they give you GPS. In flashearth.com you can converth the map into like six or seven diferent maps in a second. The different maps sites ae listed on the side of the screen it is a really cool site.

I think you might be able to do that on Earth also, I know that it gives you the GPS numbers on the bottom. All you have to do is scroll over it 7 the GPS numbers are always on the bottom. Flashearth sounds like a cool sight! I'll have to check it out when I get the chance! Do you have to download anything with it? Google Earth you have to download the program.

[pitch bait]

No you just go on there. You can get google earth maps on Flashearth.

[striper101]

No you just go on there. You can get google earth maps on Flashearth.

I just checked it out. They are a little alike each other. I still can't figure out why the numbers aren't the same. Isn't a GPS number the same no matter were you punch it in?

[Tuna Taxi]

I have a hand held GPS. I took it into the woods and recorded some oak flats and different spots that I would like to hunt. I wanted to look at them on the Flash earth site. The numbers on the site and the gps numbers that I have dont match. Is ther different Lat Lon that they would use for land surveyors purposes? The numbers that should be the same spot are


39 06.276 These are from my GPS
7450.563

39 6' 6.8 These are from flashearth.com
74 50'32.0

Im confused.

If you convert the flashearth numbers to decimal minutes instead of the min-sec format they give you, the numbers are approx:

39 06.113
74 50.533

Not exactly what your GPS gave you, but close. The precision of flashearth may not be what your GPS is, prevents the rag-heads from dialing in on targets from their computer.

There is only on lat/long for the earth, but datums and precision differences can make your position data slightly different.

[matey1]

my hand held has an option when using it for lat and lon on the terra firma to change to readings similar to what the surveyors use. go to your set up menu and see if yours does not have that also. thsi might make them closer for viewing on the web.

[megabite]

The WGS84 Map Datum used by Satellite Navigation systems uses a Zero Meridian that is 363.3 feet East of the Prime Meridian the plane of the geodetic Meridian passes through the center of the earth unlike the plane of the astronomical meridian which lines up with the plane of gravity indicated by a plum bob.the plum bob pointsto the opposite direction of the Zenith which all astronomical instruments are alighned. I think Zero Meridian 363.3 feet east of the Prime meridian might be the difference you are having problems with .

[ocnslr]

Comments about converting to the same numerical format are correct.

However, I think your error is due to different DATUMs being used.

Here is a link to more info:
http://www.alpharubicon.com/prepinfo...tumwmerrin.htm

And here is the eighth paragraph from that link:

GPS units usually default to a datum selection of WGS84. However, most USGS topo maps are still keyed to NAD27 unless they are relatively new. Most wilderness area USGS maps that I have seen don't get updated that often (not much changes out there) so they tend to be NAD27. The difference isn't huge, no more than 200 meters, but that can be significant if you are searching for a pointer to a cache. The notes on a topo map will tell you which datum it is based on and you should select that datum in your GPS setup for best accuracy. If you aren't using a map but just storing waypoints in the GPS as you go then the default WGS84 is fine.