[postgis-users] SRTM Raster Geometry question

yvecai yvecai at gmail.com
Sun Mar 4 13:25:29 PST 2012

I think one pixel= one elevation value, and :
"File names refer to the latitude and longitude of the lower left corner of
the tile - e.g. N37W105 has its lower left corner at 37 degrees north
latitude and 105 degrees west longitude. To be more exact, these
coordinates refer to the geometric center of the lower left pixel, which in
the case of SRTM3 data will be about 90 meters in extent."

All the doc is here:

Le 04/03/2012 20:53, Mr. Puneet Kishor a écrit :
> On Mar 4, 2012, at 1:39 PM, Ed Linde wrote:
>> Thanks Yves, but my question still remains though. So in this raster of
>> 1200 x 1200 pixels, does each pixel get assigned an elevation in meters of
>> "x" meters? Or do the four corners of each pixel have different elevation
>> values of a,b,c and d meters each?
>> ..
> I am guessing (albeit, based on my fiddling with SRTM a long time ago) that it is an ave value of "x" meters assigned to all the pixels in the tile. In essence, a 1200 pixel-square tile is behaving like a single large pixel with a value of "x" meters.
> Should be easy to confirm it by querying a few random pixels in a tile.
> --
> Puneet Kishor
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