[GRASS-dev] GSoC 2015: Mapnik rendering engine for GRASS GIS

[Vaclav Petras]

On Tue, Mar 10, 2015 at 4:56 AM, Luca Delucchi <lucadeluge at gmail.com> wrote:

> On 10 March 2015 at 09:47, Martin Landa <landa.martin at gmail.com> wrote:
> > Hi Adam,
> >
>
> Hi Martin,
>
> > 2015-03-09 15:37 GMT+01:00 Adam Laža <ad.laza32 at gmail.com>:
> >> I study geoinformatics at CTU in Prague and I get interested in some of
> your
> >> topics for GSoC. I have basic knowledge in C/C++ and I've already
> written
> >> some code in Python for GRASS Add-Ons.
> >> I'd like to focus on Mapnik engine, actual display drivers and graphic
> >> outputs.
> >
> > great! The proposal on the wiki [1] is somehow focused on writing
> > alternative rendering engine for ps.map [2] which is currently used by
> > wxGUI Cartographic Composer [3]. It would be probably a good idea also
> > to investigate whether would be possible to write a new GRASS display
> > driver [4] based on Mapnik libraries. In other words replacement for
> > Cairo [5] driver focused on cartographic outputs. Such driver would be
> > written in C and would require C-API for Mapnik, I found something on
> > [6], but I am not sure if it would be possible to use.
> >
>
> Good Idea to create a new driver based on Mapnik ;-)
> I never heard about the C-API for Mapnik but they should be useful. I
> could ask to Dane what is the stability of the C-API.
> Is there any way to write the driver in Python (the Mapnik Python API
> are probably more stable, used and tested than the C-API)
>
>
Adam, Luca and Martin, I agree that the cartography in GRASS GIS is limited
and I always like the idea of using another project to do the hard work for
us. However, as I see the discussion here, I would recommend you to be more
specific about the advantages, disadvantages and possible implementation of
this proposal.

For the idea itself, how it would work with Mapnik dependency once it is
implemented especially if the dependency would be through C API? What are
the chances that it will be actually used. I have in my mind that there are
still problems with Cairo on MS Windows and until recently one had to often
use PNG driver on MS Windows.

Speaking about ps.map + Cartographic Composer versus display drivers + Map
Display, I prefer the latter and I think we should specify our priorities.
If I need to start another application (or window), I can also start, for
cartography purposes, completely different application such as QGIS. Then
GRASS-QGIS connection is the think which should be improved.

QGIS map composer also has Python API if I remember correctly and it is
highly probable that one has both GRASS GIS and QGIS installed.

It is not out of interest that there was a Mapnik plugin for QGIS [1] but
it is no longer maintained [2] (ended before version 2.0 [3]).

Adam, you should also notice not only that more students can apply for one
project (idea) but also that one student can submit multiple applications
for different projects.

Best,
Vaclav

[1] http://plugins.qgis.org/plugins/quantumnik/
[2] https://github.com/springmeyer/quantumnik/commits/master
[3] http://plugins.qgis.org/plugins/quantumnik/version/0.4.1/



> > Martin
> >
>
>
> --
> ciao
> Luca
>
> http://gis.cri.fmach.it/delucchi/
> www.lucadelu.org
> _______________________________________________
> grass-dev mailing list
> grass-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/grass-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/grass-dev/attachments/20150310/c04a07f4/attachment-0001.html>