[gdal-dev] Assigning affine matrix coefficients for a new driver.

[Chaitanya kumar CH]

Rodolfo,

I don't remember how to choose the matrix to be inverted here. However you
can read about GDAL's affine transformation coefficients in the
documentation for GDALDataset::GetGeoTransform() [1]. You can also find
relevant info at the GDAL Data Model page [2].

[1]:
http://www.gdal.org/classGDALDataset.html#f9593cc241e7d140f5f3c4798a43a668
[2]: http://www.gdal.org/gdal_datamodel.html

On Wed, Jul 6, 2011 at 12:03 AM, Rodolfo Bonnin <
rodolfobonnin at suremptec.com.ar> wrote:

> Hello All,
>
> I'm working on a new PRISM driver, and it can now read the rasterbands from
> all products. Now I'm working on reading the georeferencing data, and trying
> to set the affine matrix coefficients. The format specification* says in
> page 53 for one of the map projection fields:
>
>
> Field No 58
>
> Coefficient of F4 function (a, b, c, d, e, f)
>
> x'        a     b         x        e
>      =                          +
> y'        c     d         y        f
>
> (x,y)  : Map coordinate
> (x',y') : Corrected Image address
>
> Remarks:
>
> Map projection origin = (0,0).
> In case of UTM, map coordinate at an
> intersection of the equator and UTM
> zone refelence (sic) circles of longitude = (0,0)
>
> _____
>
> * http://www.eorc.jaxa.jp/ALOS/en/doc/fdata/PRISM_L1_J_ENa.zip
>
>
> Shall I assume the affine coefficients gdal requires, are those of the
> inverse of the given matrix? Just to confirm.
> Many thanks in advance.
>
> --
> Ing. Rodolfo Bonnin
> SUR Emprendimientos Tecnológicos
>
> Perú 345  Piso 5to Oficina "B" (C1067AAG)
> Ciudad de Buenos Aires, Argentina
> Tel. +54 (11) 4342-2976/84
> rodolfobonnin at suremptec.com.ar
> www.suremptec.com
>
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>



-- 
Best regards,
Chaitanya kumar CH.
/tʃaɪθənjə/ /kʊmɑr/
+91-9494447584
17.2416N 80.1426E
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