[Gdal-dev] gdalinfo question

[Frank Warmerdam]

Clay, Bruce wrote:
> Dumb question time.
> 
>  
> 
> Given the gdalinfo dump shown below, how does one find the latitude and 
> longitude values this patch covers.
> 
> The “Corner Coordinate” numbers do not look like UTM values from my 
> untrained eye.  Are they?
>
Bruce,

The corner coordinates look like perfectly normal to me.

> Corner Coordinates:
> 
> Upper Left  (  616341.000, 4577385.000)
> 
> Lower Left  (  616341.000, 4359730.500)
> 
> Upper Right (  862125.000, 4577385.000)
> 
> Lower Right (  862125.000, 4359730.500)
> 
> Center      (  739233.000, 4468557.750)
> 
> Band 1 Block=8624x1 Type=Byte, ColorInterp=Gray

If you have PROJ.4 properly installed, gdalinfo should use it to reproject
the corners to lat/long for.  The results would look something like this
(from a file of my own):

Corner Coordinates:
Upper Left  (  440720.000, 3751320.000) (117d38'28.21"W, 33d54'8.47"N)
Lower Left  (  440720.000, 3720600.000) (117d38'20.79"W, 33d37'31.04"N)
Upper Right (  471440.000, 3751320.000) (117d18'32.07"W, 33d54'13.08"N)
Lower Right (  471440.000, 3720600.000) (117d18'28.50"W, 33d37'35.61"N)
Center      (  456080.000, 3735960.000) (117d28'27.39"W, 33d45'52.46"N)

If you have PROJ.4, but it isn't being picked by GDAL for some reason, you
can fallback on doing the conversion by hand:

eg.
   warmerda at gdal2200[393]% proj -I +proj=utm +zone=16 +datum=WGS84
   616341 4577385                                    <-- input
   85d36'34.262"W  41d20'22.412"N                    <-- output

If you don't have PROJ ... well, you will need something to do the
reprojection.

Best regards,

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