[Geotiff] Linear Units of Projections Parameters

[Frank Warmerdam]

dburken at comcast.net wrote:
> All,
> 
> Maybe this will help?
> 
> I've made a tar ball with two tiffs, one meters, one us survey feet, exact cuts.  After looking I see the major / minor axis is still in meters on the feet one (oh my god...).
> 
> Anyway I've placed the files:
> http://www.remotesensing.org/public/mtrs_feet_tifs.tgz
> 
> I think they are correct (except the axis)...
> 
> Just thought they might come in handy for testing other tools.  These swipe exactly with each other and the original (raw) landsat 7 data in ossim.

Dave,

I think the above files are both right.  The specification says the
ellipsoid semimajor axis is in "Geocentric CS Linear Units" while the
false easting is in ProjLinearUnit.  So it would seem that the ellipsoid
size is not affected by ProjLinearUnit while the false easting/northing
are.

Not too surprisingly listgeo does not report these two files as
being coincident since it mis-interpretes the false easting and northing.

feet.tif:
Corner Coordinates:
Upper Left    ( 5806041.538, 3424140.133)  (121d 7'48.66"W, 17d24'31.13"N)
Lower Left    ( 5806041.538, 3399533.883)  (121d 6'34.06"W, 17d20'59.75"N)
Upper Right   ( 5830647.788, 3424140.133)  (121d 4' 8.39"W, 17d25'42.73"N)
Lower Right   ( 5830647.788, 3399533.883)  (121d 2'53.94"W, 17d22'11.26"N)
Center        ( 5818344.663, 3411837.008)  (121d 5'21.26"W, 17d23'21.23"N)

mtrs.tif:
Corner Coordinates:
Upper Left    ( 1769685.000, 1043680.000)  ( 90d15' 7.46"W, 41d50'47.74"N)
Lower Left    ( 1769685.000, 1036180.000)  ( 90d15'19.93"W, 41d46'44.84"N)
Upper Right   ( 1777185.000, 1043680.000)  ( 90d 9'42.62"W, 41d50'38.27"N)
Lower Right   ( 1777185.000, 1036180.000)  ( 90d 9'55.44"W, 41d46'35.38"N)
Center        ( 1773435.000, 1039930.000)  ( 90d12'31.36"W, 41d48'41.59"N)

I presume the lat/long bounds for mtrs.tif are correct and the lat/long
bounds for feet.tif are being produced improperly.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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