Hi,
when I saw recent changes [1] in
grass/trunk/vector/v.mapcalc/
I realized that there is a v.mapcalc in trunk (compilation is disabled).
However, here is also a v.mapcalc in GSoC project for temporal algebra [2].
I’m wondering how they compare with each other and what is the plan?
Best,
Vaclav
[1] https://trac.osgeo.org/grass/ticket/1321
[2] http://grasswiki.osgeo.org/wiki/GRASS_GSoC_2013_Temporal_GIS_Algebra_for_raster_and_vector_data_in_GRASS#v.mapcalc
Vaclav wrote:
when I saw recent changes [1] in
grass/trunk/vector/v.mapcalc/
I realized that there is a v.mapcalc in trunk (compilation is disabled).
However, here is also a v.mapcalc in GSoC project for temporal algebra [2].I'm wondering how they compare with each other
for the old GRASS 5 v.mapcalc which is the subject of the
trac ticket, you can read about it here:
https://trac.osgeo.org/grass/browser/grass/trunk/vector/v.mapcalc/README
and for the temporal GIS v.mapcalc Thomas's wiki page that you linked to does a nice job.
AFAICT the old one is looking at math more than spatial, so perhaps a bit more like v.transform might be, than e.g. the functionality of v.overlay or v.select's GEOS tools as the temporal version might be more focused on? (I'm not really sure though, I'm just going from what I see in the README)
How the eventual-goals of both of these modules compare with what general-purpose vector ops can be done using PostGIS would be interesting to know too.
and what is the plan?
I would suggest step 1 to be your question- understand and take an inventory of what we tools we already have, and what state they are in. Choosing the best names for things can come after that. Of course for the long run we should avoid name-space collisions if we can.
regards,
Hamish
[1] https://trac.osgeo.org/grass/ticket/1321
[2] http://grasswiki.osgeo.org/wiki/GRASS_GSoC_2013_Temporal_GIS_Algebra_for_raster_and_vector_data_in_GRASS#v.mapcalc
Hi Vaclav,
2013/9/21 Vaclav Petras <wenzeslaus@gmail.com>:
Hi,
when I saw recent changes [1] in
grass/trunk/vector/v.mapcalc/
I realized that there is a v.mapcalc in trunk (compilation is disabled).
However, here is also a v.mapcalc in GSoC project for temporal algebra [2].
I'm wondering how they compare with each other and what is the plan?
The v.mapcalc version of the GSoC project focuses on boolean
operations between whole maps. It is not possible to access single
features like points, lines or areas. It was implemented so that
Thomas lean howto use lexer/parser and calling grass modules with
pygrass. The boolean vector operations are the basis for the spatial
part of the temporal vector algebra.
I am not quite sure what grass/trunk/vector/v.mapcalc/ is capable of,
or if there will be anyone willingly to finish this module?
GSoC v.mapcalc will stay in the google repository. My plan is to
cleanup and merge the code of the temporal algebra modules and to
implement t.rast3d.mapcalc using PLY, so there will be t.rast.mapcalc,
t.rast3d.mapcalc and t.vect.mapcalc. This code will then be moved into
the temporal framework in grass7.
Best regards
Soeren
Best,
Vaclav[1] https://trac.osgeo.org/grass/ticket/1321
[2]
http://grasswiki.osgeo.org/wiki/GRASS_GSoC_2013_Temporal_GIS_Algebra_for_raster_and_vector_data_in_GRASS#v.mapcalc_______________________________________________
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