[postgis-devel] [PostGIS] #231: New distance-calculations proposal

[PostGIS]

#231: New distance-calculations proposal
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  Reporter:  nicklas      |       Owner:  robe         
      Type:  enhancement  |      Status:  assigned     
  Priority:  medium       |   Milestone:  postgis 1.5.0
 Component:  postgis      |     Version:               
Resolution:               |    Keywords:               
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Comment (by robe):

 Hmm I see.  Strange.  I ran my torture ST_Distance tests against this (but
 it wasn't really designed to catch corner cases).  It did come up with
 when dealing with M and Z geometries, your distance is off by a decimal
 from the other.  I wonder if this is some other difference between 1.4 and
 1.5 and not specifically your changes.

 See below query:
 In 8.4 1.4 gives --  5.65685424949238
  4.24264068711929
 In 8.4 1.5 with your patch gives --  5.65685424949238
  4.24264068711928

 But its not a significant difference:
 --ST_Distance LineSet3D(g1, g2): Start Testing MultiLineMSet, LINESTRING

         SELECT ST_Distance(foo1.the_geom, foo2.the_geom)

                         FROM ((SELECT ST_Collect(s.the_geom) As the_geom
                 FROM (SELECT
 ST_MakeLine(ST_SetSRID(ST_MakePointM(i,j,m),4326),ST_SetSRID(ST_MakePointM(j,i,m),4326))
 As the_geom
                 FROM generate_series(-10,50,20) As i
                         CROSS JOIN generate_series(50,70, 25) As j
                         CROSS JOIN generate_series(1,2) As m
                         WHERE NOT(i = j)) As s)) As foo1 CROSS JOIN
 ((SELECT ST_SetSRID(ST_MakeLine(ST_MakePoint(i,j,k),
 ST_MakePoint(i+k,j+k,k)),4326) As the_geom
                 FROM generate_series(-10,50,20) As i
                         CROSS JOIN generate_series(40,70, 20) j
                         CROSS JOIN generate_series(1,2) k
                         ORDER BY i, j, i+j+k, k, i*j*k)) As foo2
                         LIMIT 2;

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/231#comment:8>
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