[Qgis-user] SEXTANTE for QGIS has been released

[Victor Olaya]

Paulo,

The idea (at least, my original idea) was to let users with no GRASS
knowledge to use GRASS algorithms from a more common GIS interface. So
they do not have to worry about mapsets and things like that, and they
execute the algorithm just like they would do with any other one. The
mapset and location is created automatically each time the algorithm
is run, and all data imported into it. Then the results are exported
and loaded in the GIS.

This might have some limitations, of course, but in the Java version
of SEXTANTE it has proved very useful to make those algorithms
available to most users, specially those that were a bit afraid of the
complexity of GRASS or were not used to its interface or its
command-line syntax.

Using GRASS layers is a different thing, but as I said, I hope to have
that already in a near future, and also to be able to use those GRASS
layers in other algorithms, so SEXTNATE will become the intermediate
layer for all analysis and data sources, and doing it as transparently
as possible

Regards





El día 2 de abril de 2012 11:54, Paulo van Breugel
<p.vanbreugel at gmail.com> escribió:
> On 04/02/2012 09:47 AM, Paolo Cavallini wrote:
>
> On 30/03/2012 23:19, Victor Olaya wrote:
>
> Well, the idea is just the opposite: to use any raster or vector layer
> in GRASS, directly from QGIS. "Any" in this context means any "normal"
>
>
> Please remember also that it is possible to use rasters in GRASS without
> importing them, but just registering them (r.external), with insignificant
> loss of performances. Thus, we can more or less forget about grass rasters
> in their native format, for most of the uses.
> All the best.
>
>
> Just to be clear, I assume you mean here that there is no need to convert
> (import) other raster layers to GRASS layers in order to use GRASS
> functions? I am asking because this option doesn't help the user who has
> his/her data in a GRASS database.
>
> For me the strict and transparent handling of region settings and projection
> has always been one of the strong points of GRASS, and I am curious how the
> workflow will be when working with external rasters. Like with internal
> rasters, an external raster layer does need to be in the same projection as
> the current location. Furthermore, raster functions use the region settings
> (extend, resolution) of the current mapset as far as I understand.
>
> When importing, it is possible to create a new location on the fly based on
> the raster you are importing. This makes it easier to deal with the above (I
> think), e.g., by creating a temporary location. I am not sure linking an
> external raster offers the same option (I had a quick look, but can't find
> the option, but maybe I just overlooked it). But then, the normal import
> function allows to create a location based on a raster without actually
> importing the raster. So the two could be combined.
>
>
>
>
>
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