Im trying to test if a polygon either a) touches or b) is only semi-contained by another polygon. The first is self-explanatory i guess, but the second could be many of the different predicates offered in QGIS.

I was therefore wondering if there are any more indepth explanations of the geometric predicates used in QGIS' select by location. (the only slightly basic explanation is Documentation "Join Attributes by Location" QGIS 2.18 which doesn't give any real clue as to what the terms cover)


This explanation of the Dimensionally Extended Nine-Intersection Model used by GEOS which is used by QGIS should provide the best explanation of the predicates: https://en.wikipedia.org/wiki/DE-9IM

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