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  1. MariaDB Server
  2. MDEV-3333

LP:1043845 - st_distance() results are incorrect depending on variable order

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Details

    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Fixed
    • None
    • None
    • None

    Description

      Using MariaDB 5.3.3 on CentOS 6.0

      The st_distance() function returns different results depending on the order of the variables. The results appear to be more accurate when the least complex spatial object is used as the first variable. For instance, st_distance(point, linestring) appears to consistently return accurate results but st_distance(linestring, point) often returns incorrect results depending on the linestring and point data. See below for a specific example.

      As a workaround we have had success using the least complex spatial object first where point < linestring < polygon (from a complexity standpoint).

      select st_distance(geomfromtext('
      LINESTRING(
      -95.9673005697771 36.13509598461,
      -95.9673057475387 36.1344478941074,
      -95.9673063519371 36.134484524621,
      -95.9673049102515 36.1343976584193
      )
      '),geomfromtext('point(-95.96269500000000000000 36.14181833333330000000)'))
      ;
      Result: 0.000574275965624497

      select st_distance(geomfromtext('point(-95.96269500000000000000 36.14181833333330000000)')
      , geomfromtext('
      LINESTRING(
      -95.9673005697771 36.13509598461,
      -95.9673057475387 36.1344478941074,
      -95.9673063519371 36.134484524621,
      -95.9673049102515 36.1343976584193
      )
      '))
      ;
      Result: 0.00791407398682628

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            holyfoot Alexey Botchkov
            mattwoods Matt Woods (Inactive)
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              Created:
              Updated:
              Resolved:

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