OpenStreetMap

Building generalisation: typification

Posted by Tomas Straupis on 7 September 2019 in English (English)

Second step in building generalisation is building typification. We take centroid of a building which is deemed too small for a scale, try drawing a minimal acceptable rectangle (oriented to the nearest road) and check if there would be enough free space between it and other already accepted buildings. If so - typified building is accepted, otherwise it is thrown out. Here is an example of buildings simplified and typified up to 20m: Generalised buildings Here original buildings are gray hashed, yellow ones - simplified buildings which are “large enough” for a scale, purple ones - typified buildings (note that some buildings are gone). This way we can avoid drawing random noise/snow in small scale maps: Building noise And convert them to something which communicates information that there are small buildings: Typified buildings As always, you can look at how this works in topographic map of Lithuania. Typification starts at zoom level 15 (5m), then 10m at zoom 14, 20m at 13 and finally 40m at zoom 12.

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