[Qgis-developer] GRASS Direct

[John C. Tull]

On Dec 10, 2012, at 12:44 PM, Radim Blazek <radim.blazek at gmail.com> wrote:

> The GRASS Direct is an environment developed within QGIS GRASS
> plugin/provider which makes it possible to run GRASS raster modules
> without GRASS mapset and without data conversion to GRASS format.
> Basically it is a library implementing GRASS data read/write function
> which is using QGIS providers to read/write data. In direct mode, the
> GRASS modules are run with this library instead of  the standard GRASS
> gis library.
> 
> The GRASS modules may be run in direct mode from GRASS Tools (which
> are now always enabled) if no mapset is opened. The interface is
> similar to the standard GRASS Tools apart that the region is selected
> in combo box in top of options (to be discussed) and the output is a
> GeoTIFF file. It is also possible to run GRASS modules in direct mode
> from a shell if some environment variables are set. You can see those
> variables printed in top of the output tab.
> 
> This is work in progress, so I was reluctant to announce that but
> because it had caused some compilation problems, it was necessary to
> explain a bit how it works. Currently there are only few modules
> enabled and you can find various problems. Especially it was only
> tested on Linux and most probably more fixes will be necessary on Mac
> and Windows.
> 
> I believe that GRASS Direct could also be used in SEXTANTE with a
> little work. It would be necessary however to distinguish modules
> which may be run in direct mode from those which may not (mostly
> vector modules).
> 
> Sorry for the problems I caused on Mac and Windows and many thanks to
> Jürgen and Larry for fixes.
> 
> Radim

Hi Radim,

This is a great new addition to QGIS, so thank you for you work on it.

I wanted to bring my comment I made elsewhere on my Mac testing into this, more appropriate thread:

I just tested one of the available modules on a local DEM file, and here is there error message that appeared when I ran it:

Cannot start module r.slope.aspect
command: /usr/local/Cellar/grass/6.4.2/grass-6.4.2/bin/r.slope.aspect --interface-description

ERROR: GISRC - variable not set 

Note that I am running a version of grass installed locally, not from the application that William makes available.

Cheers,
John