[GRASS-dev] Proposal: OSGeo Cartographic Library

[Glynn Clements]

Markus Neteler wrote:

> (just submitted to OSGeo-Discuss)
> 
> I would like to launch the idea of an "OSGeo Cartographic Library" to
> share concepts, source code and regression tests:
> 
> http://wiki.osgeo.org/wiki/OSGeo_Cartographic_Library
> 
> GRASS, QGIS and others are in the need of own map printing tools
> for high quality output but these projects should not start from scratch.
> There is a wealth of underlying code already in Mapserver, Mapguide etc
> which could be re-used in the terms of their respective licenses and
> certainly of programming language compatibility.
> 
> Please hack the wiki page and post your ideas.

Personally, I don't think it's practical to design such a large and
complex system at a theoretical level.

It makes more sense to start by writing what you need, structuring the
code in such a way as to make it re-usable (i.e. avoid tying it to any
particular architecture).

When you find existing code which performs a useful task, try to use
it. This will tell you whether it actually managed to meet the
re-usability critieria. If it didn't, you have concrete information
about how to improve it.

GRASS' display architecture is a prime example.

In theory, you have an abstract interface which allows you to provide
multiple different back-ends. In practice, writing a PostScript driver
demonstrates several places where the architecture isn't actually as
flexible as it needs to be, and how the interface needs to change in
order to accomodate vector back-ends.

-- 
Glynn Clements <glynn at gclements.plus.com>