[postgis-tickets] [PostGIS] #2227: Visvalingam line generalization function

[PostGIS]

#2227: Visvalingam line generalization function
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 Reporter:  strk         |       Owner:  nicklas      
     Type:  enhancement  |      Status:  new          
 Priority:  medium       |   Milestone:  PostGIS 2.2.0
Component:  postgis      |     Version:  trunk        
 Keywords:               |  
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Comment(by strk):

 Thanks about clarification on the effectiveness of the per-vertex
 indexing.
 I'm fine with the tagging-only function being named as it is currently
 (ST_SetEffectiveArea) or renamed to include some reference to Visvalingam
 and Whyatt.

 The ST_Simplify version picking ST_SimplifyDP or ST_SimplifyVW
 (Visvalingam and Whyatt) would be in SQL language, thus "inlinable".
 Basically the planner should directly see the body of the function and
 since the algorithm parameter would be a constant, it should evaluate the
 CASE portion of the code and lookup the appropriate lower function just
 once. Speed comparison should be performed on a large table :)

 Would it make sense for ST_SimplifyVW to internally call
 ST_SetEffectiveArea and then the other still missing function that only
 filters out vertices where the M value is below a given value ?

 M vs Z: I didn't know geoJSON would put M value in the Z field, and what
 about a 4d geometry ? Which would would be dropped ?

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/2227#comment:14>
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