CartoType & OpenStreetMap

Slide 1: CartoType & OpenStreetMap Graham Asher – Cartography Ltd CartoType: a portable ● map rendering and route finding library written in C++ Plug-in data sources ● How does it use ● OpenStreetMap data?

Slide 2: CartoType architecture ctm1 style sheet (xml) ctm1 accessor shp shp accessor engine font accessor graphics fonts: TrueType, context PostScript, etc. Single engine; plug-in data accessors, font accessors and graphics contexts.

Slide 3: Portability and mobile devices Slower ● Less memory ● Poor floating-point ● support (but now better) Where is the map ● data kept?

Slide 4: The CTM1 data format header Table-based binary ● global info place format layer index name index e.g., roads First split into layers ● projection Then recursive spatial ● partitioning Name index uses ● packed trie Compact: current UK ● data takes 37Mb

Slide 5: Converting OSM data to CTM1 Existing conversion ● *.osm tool reads SHP files Write new data ● New OSM accessor for OSM data + data accessor accessors Use the Expat XML ● parser (already used generate_map_data_type1 in CartoType for reading style sheets) *.ctm1

Slide 6: Routing Works with any data including OSM ● Sort points, find nodes, create arcs ● Not mature – turn restrictions not implemented ●

Slide 7: CartoType API & style sheet docs http://www.cartotype.com API docs created using Doxygen. Reasonably full description of how style sheets work. Some ideas may be useful: feature sizes based on map metres, and logarithmic feature scaling, for example.

Slide 8: Licensing CartoType commercial license: annual fee pays ● for source code, support, access to SVN etc. Considering dual license like QT but I know ● nothing... Perhaps give compiled library to free & open ● source projects Ideas welcome ● Plan to add track collection to Windows Mobile ● demo, which then becomes a free mapping tool