Hi, As a bit of a challenge I've looked at the administrative data pointed out by Nicolas Gignac: [1]. I know there are some doubts about the accuracy, but this was also meant as an exercise to deal with this kind of data. Maybe it can be reused for other purposes, although I haven't written the tool I used in a generic way. I also hope that the more accurate (1:20k) data uses the same structure.
First I converted this data to SHP (with an ESRI tool called Import71, and then ogr2ogr). Then it was converted to OSM with shp-to-osm.jar. However, the data has a topological structure, so it has not much value if it would be imported into OSM directly. The set of administrative boundaries contains municipalities, MRCs, administrative regions (17) and urban agglomerates. The municipal data contains also information about MRC, admin. regions and agglomerates, so I decided to examine this further. Now the topological structure was a benefit, because this is how administrative boundaries should also be entered in OSM. The boundaries only contain attributes like from-node, to-node, left-poly and right-poly. However, this is enough to compose relationships (type=multipolygon/boundary, boundary=administrative, etc.) out of them. Because I ended with an ArcInfo coverage as a result of the conversion by Import71, I decided to extract data from the file pat.adf to get the municipality and other relevant names, codes, etc. So far I have only created relationships, including the municipality name. I would like to share it with you, in order to gather feedback. The result can be found here: [2]. PLEASE do NOT upload this data to OSM! The ways are sorted in the relationship, so they form closed chains. Also the nodes where multiple ways meet have been deduplicated, otherwise JOSM (and also OSM itself) won't recognize the ways as being connected. The deduplication was based on the actual coordinates, not the node IDs used in the topology. Things to do: * Detect which boundary is the outer boundary, and which ones are the inner boundaries. Obviously, the ring with the biggest surface area is the outer boundary, and the rest are inner boundaries. * Add multiple municipalities in the same relationship. * Create MRCs, administrative regions, and urban agglomerates. More information about administrative boundaries can be found in [3]. For Canadian provinces admin_level=4 should be used, for regional municipalities (MRCs in Quebec) admin_level=6, and actual municipalities admin_level=8. I would like to propose to use admin_level=5 for the regions. They have at least a semi-offical status. Others might be able to elaborate on it more. This leaves the urban agglomerates (Montreal and Quebec only), for which admin_level=7 would be a natural choice, although I'm not sure if they have any official status. What do you guys think? Regards, Frank [1] http://www.mrnf.gouv.qc.ca/territoire/portrait/portrait-donnees-mille.jsp [2] http://www.steggink.org/osm/Quebec/quebec_munic.zip [3] http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative _______________________________________________ Talk-ca mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk-ca
