[geos-devel] Disconnected interior failure?

Mika Heiskanen mika.heiskanen at fmi.fi
Fri Jun 5 03:38:39 PDT 2015


We recently encountered a temperature isoband which GEOS isValidOp 
claims is invalid:

   Interior is disconnected at or near point 16.56825286557833 -6

The geometry consists of a shell plus two holes. The holes touch at a 
single point, but do not touch the shell. The description does not
match to what the ConnectedInteriorTester class reference says:

    An area Geometry is invalid if the interior is disconnected.
    This can happen if:

    * one or more holes either form a chain touching the shell
      at two places
    * one or more holes form a ring around a portion of the interior

I extracted the problematic shell plus the holes from the global data,
and made them temporarily available from http://beta.fmi.fi/geos/

QGis and MapShaper validators accept the shape made from the WKT printed 
by GEOS. Could there be a bug in the GEOS validator?


Mika Heiskanen / FMI

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