[GRASS-user] Managing the Harmonized World Soil Database in GRASS

[Luigi Ponti]

On 25/03/2011 11:44, Sylvain Maillard wrote:
> Hi,
>
> some month ago I had to make some maps with the HWSD database. I used 
> the mdbtool (http://mdbtools.sourceforge.net/) to extract all tables 
> from the .mdb file to some sql files. Then I just imported all the 
> table in a postgres database, and it is quite easy to access them in 
> GRASS ...
>
>
> Regards,
> Sylvain

Hi Sylvain,

Thanks for your answer. I see your point.

After exporting the .mdb to PostgreSQL you can db.connect to it from the 
GRASS mapset where the HWSD soil map is. However, I do not see how you 
can then get the data on the map, given that a database links to a 
vector whereas the HWSD map is a raster. How did you map the connected 
database?

It would be nice if you could share a bit more of your experience with 
mapping HWSD data.

Kind regards and thank you,

Luigi


>
>
> 2011/3/24 Luigi Ponti <lponti at inbox.com <mailto:lponti at inbox.com>>
>
>     Dear listers,
>
>     I seem to have successfully imported the Harmonized World Soil
>     Database (HWSD) in BIL format to GRASS 6.4.svn via r.in.gdal. The
>     data is available at
>     http://www.iiasa.ac.at/Research/LUC/luc07/External-World-soil-database/HTML/index.html
>
>     The HWSD is composed of a raster image file and a linked attribute
>     database stored in Microsoft Access 2003 format. According to the
>     documentation (page 28)
>     http://www.iiasa.ac.at/Research/LUC/External-World-soil-database/HWSD_Documentation.pdf
>
>     using the HWSD database in a GIS should be straightforward. The
>     MU_GLOBAL attribute column in the database is also stored in each
>     raster cell, and may therefore be considered as the link to the
>     raster.
>
>     My goal would be to obtain more raster maps that show other (soil)
>     attributes from the database or combination of different
>     attributes based on computations. The documentation suggests the
>     following work flow:
>
>     - if necessary, realize the appropriate calculations (ex: after
>     exporting from Access to Excel);
>     - convert final attributes table to a compatible GIS format;
>     - join the MU_GLOBAL attribute and the GRID value (dbf or txt
>     formats);
>     - convert the attribute to a new GRID (in the case it is needed).
>
>     What comes to mind is value replacement using r.recode but maybe
>     there is a better course of action.
>
>     This is seemingly the best available soil GIS database with global
>     coverage, so I thought my question may be useful to others.
>
>     Kind regards and thanks in advance for any hint,
>
>     Luigi
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