GeoNames Forum

Hey there, every time i need to do a lookup for an elevation i query the server, is there anyway that i could download a data file for a specific area and use it locally?

Many thanx

Xarion

Xarion

You can download the gtop30 data from the USGS web site : http://edc.usgs.gov/products/elevation/gtopo30/README.html

and the SRTM3 from NASA : http://www2.jpl.nasa.gov/srtm/

Cheers

Marc

Hey marc thanx for the input, i have downloaded the DEM files but i actually have no idea how to use them, seems like they are some sort of binary format

thanx again

Xarion

Xarion

Here the relevant part of the documentation :
The DEM is provided as 16-bit signed integer data in a simple binary raster. There are no header or trailer bytes imbedded in the image. The data are stored in row major order (all the data for row 1, followed by all the data for row 2, etc.).

It means to know the elevation at a given lat/lng you have to find the right file, get the right to bytes and convert the two bytes to an integer.

Hope this helps

Cheers

Marc