[Proj] issue with Goode's

[Maciek Sieczka]

Hi All

I've been trying to georefence Goode's MODIS imagery from GLCF UMIACS
(eg. ftp://ftp.glcf.umiacs.umd.edu/modis/500m/Eurasia/Goodes.EUAS.2000321)

I noticed that there is huge displacement when using the default Goode's
syntax in proj4. Please read below.

1. Warped the Modis scene into wgs84 projection in order to compare with
VMAP0:

gdalwarp -s_srs '+proj=goode +ellps=sphere +lon_0=30E +towgs84=0,0,0,0,0,0,0
+x_0=3335846.22854' -t_srs '+proj=latlong +ellps=wgs84
+towgs84=0,0,0,0,0,0,0' Goodes.EUAS.2000321.band3.tif
modis_goode_genuine.tif

2. Overlayed the VMAP0 "COASTLINE". Modis is vastly shifted - go figure
modis&vmap0_y_no_offs.jpg

3. Tried +y_0 offseting. 20000 seems about right -
modis&vmap0_y_20km_offs.jpg:

gdalwarp -s_srs '+proj=goode +ellps=sphere +lon_0=30E +towgs84=0,0,0,0,0,0,0
+x_0=3335846.22854 +y_0=20000' -t_srs '+proj=latlong +ellps=wgs84
+towgs84=0,0,0,0,0,0,0' Goodes.EUAS.2000321.band3.tif
modis_goode_offset20000.tif

Is it an error in proj4 or am I doing something wrong?

Another question BTW. As we move east or west from the central meridian in 
Mollweide's projection, there is a growing E distortion. Can I calculate an
optimal x_0 for Mollweide's, so the E distortion is minimalized in the area 
of my interest (a part of Poland)? How?

Using proj4.4.9, gdal-cvs-20050418.

Thanks for any clues.

Maciek 
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