Incorrect Documentation for OGRGeometry::Within and Contains

Whoops, some misleading naming slipped in. Note that "ring" is an OGRLineString -- it doesn't work at all if you use a OGRLinearRing.

Dan, could you check and confirm that you have the GEOS support built into OGR?

Yes, GEOS support is built in. OGRGeometryFactory::haveGEOS() returns true, and the within/contains functions will return true -- just not when the documentation says they will.

Oops. The documentation was backwards, but the code snippet provided is in error. Instead of being a closed square, it's a figure-eight. Done properly, the OGRLineString has no concept of "area enclosed" and returns false unless the point is lying on it (which was the case in the flawed example).

Here's a proper code snippet to test against:

/* a square (closed) */ double x[] = {0, 1, 1, 0, 0}; double y[] = {1, 1, 0, 0, 1}; OGRLinearRing ring; ring.setPoints(5, x, y);

OGRPolygon loop; loop.addRing(&ring);

OGRPoint middle; middle.setX(0.5); middle.setY(0.5);

std::cout << "**********************************************" << std::endl; std::cout << "OGRGeometryFactory::haveGEOS(): " <<OGRGeometryFactory::haveGEOS() << std::endl; std::cout << "middle.Contains(&loop): " << middle.Contains(&loop) << std::endl; std::cout << "middle.Within(&loop): " << middle.Within(&loop) << std::endl; std::cout << "loop.Contains(&middle): " << loop.Contains(&middle) << std::endl; std::cout << "loop.Within(&middle): " << loop.Within(&middle) << std::endl;

Results: ********************************************** OGRGeometryFactory::haveGEOS(): 1 middle.Contains(&loop): 0 middle.Within(&loop): 1 loop.Contains(&middle): 1 loop.Within(&middle): 0

Test presenting difference between actual/target geometry in Withing/Contains and other OGC predicates

Fixed in trunk (r13128).