[GRASS-user] GRASS 7 d.vect.thematic, how to automatically generate breaks and assign colors and make a psmap legend?

[Moritz Lennert]

On 05/02/15 21:38, James Powell wrote:
>
> In the upgrade from GRASS 6.4.2 to GRASS 7, d.vect.thematic seems to
> have changed significantly.  This is my tool of choice for making a
> legend for vector layers.  For example, given a street map of lines
> called streetswm, and a column dacount indicating vehicles counted on
> a given segment, and with a monitor open, the simplest but still very
> useful d.vect.thematic command is:
>
> d.vect.thematic map=streetswm at PERMANENT type=line column=dacount \
>    themetype=graduated_colors themecalc=interval nint=8 \
>    colorscheme=blue-red psmap=testthem2
>
> In 6.4.2, that outputs both the legend and a nice thematic map using
> psmap syntax.  Will you please advise me on the equivalent process for
> GRASS 7?  I have looked in the 7.0.0RC-News and in the code for
> d.vect.thematic itself but for example the keyword "graduated" or
> "theme" appears nowhere in either.
>
> To be clear, I am looking for two separate features:
>
> 1. To automatically generate breaks and assign colors to them.  I just
>     say "gimme 8 intervals in the blue-red" and I get out intelligence
>     like "text 14% 54% 632.339 - 752.795 " (from
>     testthem2\_legend.psmap).
> 2. To automatically generate psmap commands, especially for the legend,
>     reflecting the breaks and colors automatically assigned in step 1.
>
> I really appreciate your help.  I'm running GRASS GIS 7.0.0svn (r63888).

You are right that the C-module version is less feature-rich in some 
aspects than the original script version. Please file enhancement 
requests against that module for the different feature you would like to 
see (altough discussions are ongoing on whether this module should 
actually continue to be developed or not, see [1]).

The old script module is still available as an addon under the name 
d.vect.thematic2 [2] and should be easy to install.

Moritz

[1] http://lists.osgeo.org/pipermail/grass-dev/2015-January/072918.html
[2] http://grass.osgeo.org/grass70/manuals/addons/d.vect.thematic2.html