[GRASS5] global wrap around problem in G__read_Cell_head()

Markus Neteler neteler at itc.it
Thu Jan 26 10:45:10 EST 2006


when trying to export LatLong SPOT VGT satellite data with
the following cellhd file:

proj:       3
zone:       0
north:      75:00:16.071429N
south:      56:00:16.069919S
east:       179:59:43.924424E
west:       179:59:43.928571E
cols:       40320
rows:       14673
e-w resol:  0:00:32.142857
n-s resol:  0:00:32.142857
format:     0
compressed: 1

I get:

r.out.tiff -t 0001_NDV out=test
D0/0: N:75.004464 S:-56.004464
D0/0: W:179.995536 E:539.995535

the W/E values confuse QGIS or other GIS software
later (also me).

It seems that G__read_Cell_head() doesn't handle the
wrap around as needed.

The map position looks almost ok (precision issue?), I have
overlayed VMAP0 vector data.

How and where to fix that?


PS: The original SPOT coordinates in 0001_LOG.TXT are
  CARTO_UPPER_LEFT_X        -180.000000
  CARTO_UPPER_LEFT_Y          75.000000
  CARTO_UPPER_RIGHT_X        179.991071
  CARTO_UPPER_RIGHT_Y         75.000000
  CARTO_LOWER_RIGHT_X        179.991071
  CARTO_LOWER_RIGHT_Y        -56.000000
  CARTO_LOWER_LEFT_X        -180.000000
  CARTO_LOWER_LEFT_Y         -56.000000
  CARTO_CENTER_X              -0.004464
  CARTO_CENTER_Y               9.500000

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