[postgis-devel] [PostGIS] #785: Topology functions should be tolerance aware

[PostGIS]

#785: Topology functions should be tolerance aware
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 Reporter:  robe         |       Owner:  strk         
     Type:  enhancement  |      Status:  new          
 Priority:  medium       |   Milestone:  PostGIS 2.1.0
Component:  topology     |     Version:  trunk        
 Keywords:               |  
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Comment(by strk):

 With r9395 I added an internal _ST_MinTolerance taking a topology name and
 an geometry (an extent). The function will lookup in
 topology.topology.precision and give that value back, while computing a
 minimum tolerance if topology.topology.precision is still zero.

 The extent passed serves the purpose of computing the minimum tolerance,
 taking into account the floating point nature of the ordinate values and
 thus the increasing cell size in the precision grid.

 Use of _ST_MinTolerance is currently restricted to ToTopoGeom and the
 auxiliary TopoGeo_AddPoint, TopoGeo_AddLinestring and TopoGeo_AddPolygon.

 It'll help having a function (TopologySummary?) check the consistency
 between a topology tolerance and the minimum tolerance required to account
 for changes in the outermost boundary of the current topology extent.
 Also, it may be useful to allow an "extent" parameter into CreateTopology
 so that the topology tolerance is computed internally.

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/785#comment:5>
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