On vendredi 2 mars 2012, Peter Körner wrote: > By defining algorithms to work with relations in one place and mapping > relation-types to that algorithms in another place.
The idea looks sexy, but relations have so many different construction that you will probably end with as much algorithms as there are relation types. > For example: Let's see what exists : type=multipolygon --> build-polygon (but waterway=riverbank and some lakes are constructed with touching outer rings loosing the true geometry, if proper processing is needed we whould need special tweaks of those cases) type=multipolygon are note expressly said to allow nested relations type=boundary --> almost build-polygon, but some members sneaked their way as subareas while not part of the geometry and roles are different. In those there are cases where nested relation are forming the geometry type=site (relation become categories ?)--> build-polygon but only for members with role=perimeter and tags are pushed down type=route --> build-linestring but only one route/(blank), and conditionnal on those backward/forward/north/south/east/west type=waterway --> build-graph special to handle the main stream and the side streams to build a graph and not a linestring (special handling at GIS side because it doesn't exist as valid WKT) type=street/associatedStreet --> build-linestring with role conditions There are others, but each might need some special roles conditions and the way tags apply to what might be kind of special > The goal should be reducing the number of algorithms and re-using them > as much as possible. I understand the goal, but fear that it won't be so easy -- sly qui suis-je : http://sly.letuffe.org email perso : sylvain chez letuffe un point org _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
