GDAL/r.in.gdal and attribute support (vat.adf)

[Markus Neteler]

Frank,

today I imported a AIGRID (binary) into GRASS and realized that the vat.adf is not imported. It would be great to have this feature.

For illustration I have uploaded: sample_aigrid.tar.gz and the related cats file soil_covBZ.grasscats which I contructed manually from analyzing the vat.adf. Its structure seems to be sequential.

If GDAL is able to "send" the attributes, we may write the cats ASCII file in the location.

Thanks in advance,

Markus

[warmerdam]

Andrey,

Could you look into this as a first "GDAL" task?  The AIGrid reader is 
in gdal/frmts/aigrid. 

The file Markus has uploaded is at
ftp://gdal.velocet.ca/pub/incoming/sample_aigrid.tar.gz. It appears that the
vat.adf file is the data file component of an ESRI "info" dataset.  If that
is the case, the "schema" definition of the vat.adf file should be in an info
directory "parallel" to the grid coverage directory, but Markus did not supply
that.  You may need to contact him to get the contents of this info directory.

Information on the INFO file format is contained within the Arc/Info binary
vector coverage analysis at:

  http://pages.infinit.net/danmo/e00/docs/v7_bin_cover.html

There is code already in gdal/ogr/ogrsf_frmts/avc for reading vector coverages,
including the support for reading info datasets, so this should not need to
be reimplemented from scratch.  I presume the information we can get from 
the vat.adf file will be represented in GDAL as category names.  This would be
accomplished by overriding the GDALRasterBand::GetCategoryNames() method ...
something I don't think I have yet done for any GDAL format.  Please feel free
to ask questions while you work on this one.

[neteler@…]

Hi,

finally I got the missing INFO directory for the AIG support.
I have stored it here:
ftp gdal.velocet.ca
pub/incoming/bodenbed_arc_cov.tar.gz

Good luck!

 Markus

[warmerdam]

Markus,

This last summer I implemented VAT support in the AIGRID driver. It is available as a "raster attribute table" through the driver. Raster attribute tables are also available for the HFA (Erdas Imagine) driver.