Well, I looked at it in QGIS and the line seems to cross the border of the polygon. I have attached the part of the polygon where it crosses, with the line in violet and the intersecting part in green.
/Nicklas On Tue, 2011-01-25 at 15:00 -0500, Bryan Montgomery wrote: > Hello, > Is there a way to debug a problem I have with a polygon and line? I > was running a query that used st_intersects and st_intersection to get > the length of lines that are within the polygon. I was spot checking > some of the data and came up with a particularly strange example. > > Visually, the polygon looks as it should, the line clearly appears to > be completely contained within the polygon however st_crosses returns > true and intersection returns a subset of the line. I've tried this on > postgis version 1.3 and 1.4 and both behave the same. I'm inclined to > believe there is a stray point but given the polygon 2,700+ points I'm > not sure how I find it! I suppose it's possible that there is a bug - > or maybe I'm just completely missing something. > > I tried finding the closest point on the polygon to the line - but > when I tried to find a way to do this it seemed that the suggestions > were for finding the closest point when the other point was outside > the polygon? > > Appreciate any help, > > Thanks - Bryan. > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users
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