[geos-devel] [GEOS] #1007: GEOSNearestPoints_r for prepared geometries

GEOS geos-trac at osgeo.org
Tue Dec 17 11:28:45 PST 2019

#1007: GEOSNearestPoints_r for prepared geometries
 Reporter:  ndawson      |       Owner:  geos-devel@…
     Type:  enhancement  |      Status:  new
 Priority:  minor        |   Milestone:
Component:  Default      |     Version:
 Severity:  Unassigned   |  Resolution:
 Keywords:               |

Comment (by ndawson):

 I'm hitting this one during the qgis label placement engine candidate
 costing code. Qgis first generates a ton of potential candidate label
 positions (basically via a grid over the polygon), and then ranks them by
 calculating the distance of the label to the boundary of the polygon. (So
 labels further from boundaries are preferred). This involves hundreds of
 calls to GEOSNearestPoints for a single polygon.

 I can't find any documentation regarding GEOSDistanceIndexed (anywhere!).
 Does it maintain an index between calls? Is there any downside of using
 this over GEOSNearestPoints?

Ticket URL: <https://trac.osgeo.org/geos/ticket/1007#comment:2>
GEOS <http://trac.osgeo.org/geos>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).

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