[GRASS-dev] New georectifying module in TclTk

[Maciek Sieczka]

On Tue, 06 Jun 2006 08:28:14 -0700
Michael Barton <michael.barton at asu.edu> wrote:

> Thanks. That is helpful. It will be certainly easier if I only am
> doing rms calculations using one equation. Still, I wonder can
> minimizing errors using an affine transformation produce poorer
> results for polynomial transformations?
> 
> Also, in responding to my own comment yesterday... I looked at
> gdalwarp last night and I'm not sure it could replace i.rectify as
> is. If there is someway to specify a set of GCP's that are not
> embedded in the raster file format, I didn't see it in the docs.

1. 'gdal_translate -gcp' to add GCPs to raster
2. 'gdalwarp' to warp using those GCPs

> Also, I didn't see any way of using it to do error calculations
> (though this might be moot).

Not in the verbose gdalwarp output AFAIK.

> GDAL will also need to to GRASS to GRASS
> file formats. I know this was a problem awhile back, but perhaps it
> is not one now.

AFAIK Grass raster and vectors are supported only for reading. I've
been using it for e.g. QGIS and it works very good.

> More interestingly, it might be more possible to wrap v.transform
> into the georectifier so that it will do both raster and vector
> files, if this is of any interest to people.

Maybe a good idea. If this also enables us to overlay raster and vector
in the reference window, to select GCPs for raster from vectors and
vice versa, it could be really usefull.

Maciek

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