[GRASS5] GRASS and MODIS V004 SIN projection?

[Markus Neteler]

John,

thanks for the hint! But since 12/2002 they produce all data
in SIN (additionally?) which is much simpler to handle in
GIS. Also all old data were reprocessed.

The MODIS Reprojection Tool also supports SIN so we
can use that.

Markus

On Fri, Nov 07, 2003 at 02:56:31PM -0500, John Gillette wrote:
> Markus,
> This is a little late but ...
> >From http://hdfeos.gsfc.nasa.gov/hdfeos/softwarelist.cfm
> under HDF & HDF-EOS Utilities is a path to download the 
> ECS project version of GCTP which has:
>   ISINUSFOR.C 
>   ISINUSINV.C
> 
> "Integerized Sinusoidal Library Functions - library routines to 
>  perform mapping to and from the Integerized Sinusoidal.  These  
>  functions perform the mapping from projection coordinates (x/y)  
>  to the geographic coordinates (longitude/latitude)."
> 
> from web page:
> "In developing HDF-EOS, several bugs were identified and 
>  corrected in the GCTP code. Since the USGS has 
>  dropped support for the code, the ECS project now 
>  maintains its own custom version of the library source. The 
>  ECS version of GCTP incorporates all the bug fixes and a 
>  new projection (the Integerized Sinusoidal Projection; 
>  projection code 99)."
> 
> Hope this helps.
> 
> John
> 
> 
> 
> -----Original Message-----
> From: Markus Neteler [mailto:neteler at itc.it]
> Sent: Friday, August 01, 2003 9:49 AM
> To: grass5 developers list
> Subject: [GRASS5] GRASS and MODIS V004 SIN projection?
> 
> 
> 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
> 
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-- 
Markus Neteler     <neteler at itc.it>       http://mpa.itc.it
ITC-irst, Istituto per la Ricerca Scientifica e Tecnologica
MPBA - Predictive Models for Biol. & Environ. Data Analysis
Via Sommarive, 18        -       38050 Povo (Trento), Italy