[Gdal-dev] Does gdalinfo Bounding Box Information really match DTED / SRTM ?

[Vincent Schut]

On Mon, 29 Jan 2007 23:43:49 -0800 (PST)
Michael84 <michael.timo.welsch at gmx.de> wrote:

> 
> I use gdalinfo to extract bounding box information of DTED L0&L1
> (dt0, dt1) as well as SRTM (hgt over bil+hdr+proj solution) data.
> In both cases the reported corner points are not integer values as
> supposed. 
> 
> Corner Coordinates: (DTED)
> Upper Left  (  -0.0041667,  49.0041667) (  0d 0'15.00"W, 49d
> 0'15.00"N) Lower Left  (  -0.0041667,  47.9958333) (  0d 0'15.00"W,
> 47d59'45.00"N) Upper Right (   1.0041667,  49.0041667) (  1d
> 0'15.00"E, 49d 0'15.00"N) Lower Right (   1.0041667,  47.9958333)
> (  1d 0'15.00"E, 47d59'45.00"N) Center      (   0.5000000,
> 48.5000000) (  0d30'0.00"E, 48d30'0.00"N)
> 
> Is this is a roundig bug of gdal or are the data sources just coded
> like this ?

Possibly because gdal uses the corner of the pixels as reference, and
the DTED and SRTM spec use the center of the pixels? They seem to be
just half a pixel off...

Cheers,
Vincent.