[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):

 About distance vs. area, what about taking the square root of the area as
 a parameter ?
 If the aim is hiding distortions within a device pixel the pixel side
 would be a valid value for both functions (elevated to a power of 2 for
 the area). But maybe it is better not to complicate the matter too much,
 and just let people rely on documentation. NOTE: in order to avoid the
 overhead of parsing the algorithm name for every record in a table it
 could be wise to turn ST_Simplify into an inlinable SQL function simply
 relaying the call to differently-named functions (ST_SimplifyDP,
 ST_SimplifyVisvalingam); at that point you could just provide the
 specifically-named one for Visvalingam here.

 About retaining the M value, that's surely a useful option to have.
 The only reason to encode the effective area into M (or, again, in Z) is
 if that's useful to dynamically simplify on the client. It is still not
 clear to me how that part works.
 Is it possible for the client to just use the by-vertex value to decide
 what to drop and
 what not to drop or does the client still need to compute further
 "effective areas" on every
 vertex drop (for the adjacent ones)?

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/2227#comment:12>
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