[postgis-tickets] [PostGIS] #2093: Add extra policy argument to control ST_Simplify behavior

[PostGIS]

#2093: Add extra policy argument to control ST_Simplify behavior
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 Reporter:  robe         |       Owner:  strk         
     Type:  enhancement  |      Status:  new          
 Priority:  medium       |   Milestone:  PostGIS 2.2.0
Component:  postgis      |     Version:  trunk        
 Keywords:               |  
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Comment(by strk):

 I'd note that for the mapnik case a 3-vertices ring would also be enough
 to render (and would be 3/4 the size of the 4-vertices ring...). So maybe
 we need to be able to specify exactly the minimum number of vertices for
 tipology... Let's see if it could be expressed with an integer for each
 type:

  minimum number of points:

    - 0: null for collapsed lines or shells, removed for holes
    - 1: single vertex line for lines, single vertex ring for rings
    - 2: structurally valid for line, structurally invalid for rings
    - 3: structurally valid for line, structurally invalid for rings, but
 good enough for mapnik
    - 4: structurally valid for line, structurally valid ring

 The conversion from line to point and from ring to line or point we could
 omit from the function completely.
 ST_MakeValid can do that, and it would be expensive to ensure topological
 validity anyway, even if we have
 multiple points.

 So with this approach you'd basically only have to specify an integer for
 each category.
 Does it sound flexible enough  so far ?

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/2093#comment:19>
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