GPS Coordinates

deprecated · Post by **deprecated** » Sat Mar 19, 2005 10:32 pm

What is the best way to implement gps coordinates into a terrain?

Thanks for your help!

Guest · Post by **Guest** » Mon Mar 21, 2005 10:30 am

Errr

In real life that would involve launching a bunch of expensive satellites and using a GPS receiver on the ground. But my guess is you don't want to go through all that trouble...

A little more information about what you mean would be nice.

If you mean "how do I show grid coordinates" that's just a matter of dividing Z and X by the gridsize and adding an offset.
(Using the simplification of a flat world, not a spherical one)

deprecated · Post by **deprecated** » Mon Mar 21, 2005 3:34 pm

If you mean "how do I show grid coordinates" that's just a matter of dividing Z and X by the gridsize and adding an offset.
(Using the simplification of a flat world, not a spherical one)

Ok, sorry for being vague...

What I am up to is this,

I am getting DEM files from USGS that I convert into heightmaps (.bmp)
then load the terrain into Irrlicht...

Now, I have the terrrain, that I can walk around on...

What If I want to figure out approx. where I am in "real world coordinates" while walking around within my irrlicht terrain?

Do I use a method similar to the one you speak of?

BTW, The DEM files provide coordinates, if I open up the file.

What is the best way to implement lat/long coordinates...

Will I have problems with hills and valleys...

Guest · Post by **Guest** » Mon Mar 21, 2005 6:35 pm

I think the DEM format may not be cartesian (I mean: I think it can support fan-like maps), but if you use a small high-res one (7 minute I believe), the difference is probably not noticeable.

When you convert your DEM to BMP, of course you lose all kinds of interesting information - the origin (long/lat/alt) and orientation of the DEM. So you'll need to include that information in some other way.