[Gdal-dev] goode homolosine projection

[Vincent Schut]

Manuel, Frank,

I just want to say thank you, this is what I have been waiting for :-)
Till now I tried reprojecting modis datasets from goode's homolosine by 
cutting the image into pieces which I seperately reprojected using either a 
sinusoidal or a mollweide projection, using the parameters from 
http://gis.esri.com/library/userconf/proc98/PROCEED/TO850/PAP844/P844.HTM. 
This patch will make my life easier...

One question though, because you mention reprojecting modis datasets. I read 
somewhere on the proj mailinglist 
(http://remotesensing.org/lists/proj_archive/msg03772.html) that for 
reprojecting from different ellipses (sphere -> WGS84), one needs to specify 
the '+towgs84=0,0,0' parameter too. Do you know it this is correct and still 
necessary? I think the correct phrase to reproject modis from goode's 
homolosine (sphere) to longlat WGS84 then will be something like:

gdalwarp <input> -s_srs '+proj=goode +ellps=sphere +towgs84=0,0,0 +lon_0=100w 
+x_0=-11119487.43'  <output options>

Needless to say I hope this patch will be in cvs soon... But I'll apply the 
patch locally and test it a bit on my modis data of Indonesia, and keep you 
informed on the results (no news is good news is an applicable dutch saying 
here).

Regards,
Vincent Schut.


On Wednesday 10 March 2004 18:20, Frank Warmerdam wrote:
> Manuel Massing wrote:
> > Hello,
> >
> > Attached is a small patch to add OGR support for the goode homolosine
> > projection.
> >
> > Unfortunately, proj.4 does only support the uninterrupted form of the
> > goode projection,  so a reprojection won't work on global datasets in
> > interrupted form.
> > However, in a local context, you can adjust false easting and central
> > meridian values for the different zones. For a listing of false easting
> > and central meridian values used in the interrupted form, refer to Table
> > 1 of http://edcdaac.usgs.gov/1KM/goodesarticle.asp.
> >
> > To reproject e.g. a MODIS dataset of North America
> > (ftp://ftp.glcf.umiacs.umd.edu/modis/500m/North_America/Goodes.NA.2003321
> >/), you could use the command-line:
> >
> > gdalwarp <input> -s_srs '+proj=goode +ellps=sphere +lon_0=100w
> > +x_0=-11119487.43'  <output options>
>
> Manuel,
>
> Would you mind submitting the patch via bugzilla?  I generally hate to add
> new projection forms to OGR (thereby setting a WKT representation in stone)
> till I have also reviewed ESRI and other WKT sources to see if they already
> have a format for that projection.  Handling it through bugzilla will give
> me the time to review and look at other sources before doing anything.
>
> I would add that the interrupted form is what I really want to (as far as
> I understand it).
>
> Best regards,

-- 
-----------------------------
 Vincent Schut
 SarVision B.V.
 Wageningen, The Netherlands
 www.sarvision.com