Request: add 'clip' operator

[jipclaassens]

The current sub-operator can only cut out a polygon that has a matching domain or a void domain. What if I want to cut a different polygon set?

For example, I want to cut out all main roads (polygons) from a parcel polygon set. To my knowledge this is now not possible.

In ArcGiS, this operator is called 'clip':

[jipclaassens]

Met Boost geometry zou dit sneller kunnen

Nu kan het met overlay_polygon, enkel in integers

[MaartenHilferink]

hoe presteert:

fpolygon(mul(ipolygon(INPUT), ipolygon(CLIP_FEATURE)))

of, korter:
fpolygon( ipolygon(INPUT) * ipolygon(CLIP_FEATURE))
?

@jipclaassens please provide feedback and we'll look into expected performance improvement with a boost geometry implementation.

[jipclaassens]

@MaartenHilferink, this works indeed. However, even for a relatively small dataset, it is very slow.

With a simplified (at 10 meters) BBG of Amsterdam and with a smaller rectangular clip feature, it still takes quite a while. It calculates for the last 3 hours and still needs to finish.

[jipclaassens]

Project:
https://github.com/ObjectVision/BegrenzingBebouwdGebied.git

Make studyarea .fss
/SourceData/BBG/MakeStudyArea
or
Paste the attached fss in the relevant LD folder: ..\LocalData\begrenzingbebouwdgebied\BBG

Mul test case:
/SourceData/BBG/StudyArea/test
StudyArea.zip

[MaartenHilferink]

Rekentijd test (m.b.v. boost::polygon) 4 sec, test2 (m.b.v. boost::geometry's bg_intersect): direct, < 1 sec.

[MaartenHilferink]

overlay_polygon is now also applicable on fpoint and dpoint arguments, by using boost::geometry

[MaartenHilferink]

Remaining todos:

• allow cog_mul, cog_and for bg_intersect on floating point point sequences
• cog_sub, bg_difference
• cog_or, cog_add, bg_union
• bg_overlay_polygon as alternative for overlay_polygon on integer coordinates

[MaartenHilferink]

[jipclaassens]

@MaartenHilferink does this mean there new operators:

• bg_intersect
• bg_union
• bg_xor
• bg_difference
• bg_overlay_polygon
• bp_overlay_polygon

In that case, we need to update the documentation.