I've started a geovisualization / mapping library project. The library 
depends on GDAL and GNOME (especially Rsvg and Cairo) related libraries. 
There are others but these are my choices. C is my choice as the 
programming language (it is used by many GNOME libraries). My use case 
will mostly be interactive desktop visualization, so I'm interested in 
speed and explorative features.

The beginnings are at http://map.hut.fi/files/gvl/. The library can 
currently draw points, lines and polygons on a Cairo surface. The idea 
is to use Pango text rendering. Raster will be drawn with vector 
symbolizers or (to image surface) pixel based. Classification or 
interpolation will be done with user supplied callback functions for 
filtering.

The data model of the library attempts to be similar to the OGC 
symbology encoding (se) so that it would be possible to create 
symbolizers from se XML files and vice versa. However, parsing and 
creating XML files is probably out of the scope of this library.

This project is related to the OSGeo Cartographic Library proposal: 
http://wiki.osgeo.org/wiki/OSGeo_Cartographic_Library

If anybody is interested in collaboration, please let me know.

Regards,

Ari

-- 
Prof. Ari Jolma
Geoinformatiikka / Geoinformatics
Teknillinen Korkeakoulu / Helsinki University of Technology
tel: +358 9 451 3886 address: POBox 1200, 02015 TKK, Finland
Email: ari.jolma at tkk.fi URL: http://www.tkk.fi/~jolma