[OSM-dev] Polygon relationificator

Iván Sánchez Ortega ivan at sanchezortega.es
Mon Sep 14 12:29:13 BST 2009

Hi all,

During the imports support group conference call, the question of import tools 
was raised.

I can't quite recall everyone's point of view, but I think that the general 
idea was "the more tools, the better".

I'm all for an unix-like approach: lots of small specialised tools, that work 
together in order to do an import. Right now we got conversors, filters, 
uploaders and whatnot.

But one thing I'm missing is a "polygon relationificator". Let me explain.

Let's suppose I've got a shapefile/GML/spatialite file full of polygons; and 
such polygons do not overlap each other, and are adjacent to each other to 
cover a large area. Think land use and administrative areas.

And, as defined in http://wiki.osm.org/wiki/Multipolygon , we can have 
multipolygons with several outer ways - which will be joined together when 
exporting to another format (e.g. osm2pgsql).

You can see where this goes. If the input polygons are non-overlapping and 
adjacent, I could redraw the edges of the polygons as graph edges, put a 
graph node whenever three (or more) polygons touch each other, and then apply 
some graph theory to convert every polygon to a set of graph edges ( = 
relation of ways = multipolygon with several outer ways )

IMHO, this would be good not only for data imports, but also for integrity 
checks (detect overlaps) and cleanup, given OSM input and OSM output.

Question is:

Is such a tool available? If not, who has interest in making such tool?

Iván Sánchez Ortega <ivan at sanchezortega.es>

La tradición es la personalidad de los imbéciles.- Maurice Ravel.

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