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I'm new to GIS. I want to calculate the elevation of any point on earth giving lat, Long (for example like google elevation Api, or the earth tools: http://www.earthtools.org/webservices.htm # cheigit) based the ASTER GDEM MODEL V2 I went to download data from there, and gives me geotif files. Then what should I do? Thanks

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Welcome to GIS.stackexchange. This thread is receiving downvotes because it does not seem to be well-researched. It sounds like a "do my homework" question. You can improve it by specifying what exactly you want to do and what you already tried. – underdark♦ Jan 23 at 10:05

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Each pixel/tile in the geotiff represents a height measurement. Since it's not an ordinary but a Geo-referenced tiff (raster image) you can compare it with any other georeferenced polygon or point location to recover the height measurement(s) that apply to it.

Before we help you any further I suggest you try and combine your set with the geotiff and show us what you're doing exactly. For more info on how to communicate this, see also this link

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int-arch-photogramm-remote-sens-spatial-inf-sci.net/XXXIX-B4/… en.wikipedia.org/wiki/EGM96 about what elevation you get from those files – simplexio Jan 23 at 11:54
I want to make a database (myslql) which will give (lat, Long) and will get altitude – user14499 Jan 23 at 16:05
@simplexio Thanks for the paper, it's an interesting read. However, it tells us mostly about the quality of the DEM's, not really about how to use it. Either way, I think user14499 should show is a bit more about the attempt as underdark's comment suggests. – Jur_ Jan 24 at 15:04
@user14499 , i would recommened getting latest PostgreSQL + PostGIS if possible, so you can do your data analysis in database. Another option is do it middleware. Point about pasted pdf was to underline fact that ASTER data uses EGM96 elevation model, so you need to have do conversion to get meters from sea level etc... – simplexio Jan 25 at 9:18

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