[OSGeo-Discuss] Proposal: OSGeo Cartographic Library
crschmidt at crschmidt.net
Sun Apr 13 05:58:37 PDT 2008
On Sun, Apr 13, 2008 at 11:18:48AM +0300, Ari Jolma wrote:
> I'm still very much interested in this. Cairo would provide a single API
> to render to an image buffer, on PDF and others. It has good support for
> rendering text with various fonts and there are high-level language APIs.
> Currently Cairo can be used in Geoinformatica to render geodata,
> legends, etc. on a map. I'm already using that a bit and will use it
> much more in the future.
I think that for the task you've described, looking into Mapnik might
be a good idea.
> What I think is needed first, and would be the core content of the
> library is 1) a mapping of style information into Cairo commands, 2)
> capability to render cartographic symbols on maps, and 3) a mechanism to
> allow plugins that add legends etc. on the map, 4) symbol and label
> placement algorithms. Second need would perhaps be support for various
> geovisualization methods.
1), 2), and 4) already exist in Mapnik. 3) seems to me like it can
either be added to Mapnik, or added via post-processing, without needing
to reimplement 1), 2) or 4).
> Cairo is of course just one technology and not suited for all needs in
> this domain. Furthermore, the data provider can be made separate from
> the library, but I'd like to start with and use GDAL (OGR in fact) as
> the default.
Mapnik has support for PostGIS and Shapefiles, but has a plugin-based
architecture for reading data, so I would not be surprised to find that
an OGR plugin for data access would be too difficult for someone
experienced in C++/C.
> Anyway, I'd like to finally get going with this and start drafting an
> API. Any ideas how to proceed? Set up a svn repository somewhere?
I'd strongly recommend starting by looking at existing solutions.
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