[GRASS5] GRASS and MODIS V004 SIN projection?

[Markus Neteler]

Dear developers,

to process MODIS V004 data which are projected in SIN (Sinusoidal)
projection, I would like to know which projection to choose
in GRASS:

fouc_s:Foucaut Sinusoidal
gn_sinu:General Sinusoidal Series
sinu:Sinusoidal (Sanson-Flamsteed)

I assume that it is none of above: The MODIS metadata refer
to GCTP_SNSOID. In the GCTP there are two files:
gctp/sinfor.c
gctp/sininv.c

"NAME                            SINUSOIDAL

PURPOSE:        Transforms input longitude and latitude to Easting and
                Northing for the Sinusoidal projection.  The
                longitude and latitude must be in radians.  The Easting
                and Northing values will be returned in meters.
"

The required parameters for GCTP_SNSOID are:
"static double lon_center;       /* Center longitude (projection center) */
static double R;                /* Radius of the earth (sphere)         */
static double false_easting;    /* x offset in meters                   */
static double false_northing;   /* y offset in meters                   */
"

The MODIS V004 LST metadata say (excerpt from
 http://mpa.itc.it/markus/modis/MOD11A1.A2000055.h18v04.004.2002355023354.StructMetadata.0 
):
                UpperLeftPointMtrs=(0.000000,5559752.598833)
                LowerRightMtrs=(1111950.519767,4447802.079066)
                Projection=GCTP_SNSOID
                ProjParams=(6371007.181000,0,0,0,0,0,0,0,86400,0,0,0,0)


The HDFEOS software interprets above:
http://asl.umbc.edu/pub/motteler/hdf/hdfeos/hdfeos/src/GDapi.c
intn
GDprojinfo(int32 gridID, int32 * projcode, int32 * zonecode,
	   int32 * spherecode, float64 projparm[])

-> projparm[0] = 6371007.181000
-> projparm[8] = 86400

Probably it's easy to define this in GRASS?

Thanks in advance,

 Markus