[postgis-users] ST_Transform troubles

Mike Toews mwtoews at gmail.com
Mon Jun 27 03:44:08 PDT 2011


On 27 June 2011 19:54, Frans Knibbe <frans.knibbe at geodan.nl> wrote:
> To me the argument "We are ignoring the standard because everyone else is
> doing the same" comes across as rather weak. The whole point of standards is
> that you comply with them, otherwise they are useless. I fully agree that
> having different axis orders is a big nuisance. But not complying with
> standards can be a nuisance too.

I think it is well established among most (all?) spatial DBs that
comply with OGC Standards that the coordinate order is Cartesian: "X
Y" or "Longitude Latitude". If there is any issues with this, then it
is with the OGC Standards you disagree with. Mind you, this is only an
internal ordering in WKB, that you may occasionally see in WKT. Both
of these are computer markup languages, not designed to look pretty in
a report. However, if you do want to make the coordinate look more
human readable, it is rather simple to write your own function to
report coordinates in any style you like.

An interesting case study of following OGC Standards for coordinate
ordering is with MS SQL Server 2008 Spatial's GEOGRAPHY type. When the
preview was released, coordinate order of WKT was "Lat Lon", but was
reversed to "Lon Lat" for the subsequent preview and final release.
See the following links for more:
http://social.msdn.microsoft.com/forums/en-US/sqlspatial/thread/41250c42-25e6-4de7-953e-a6c41ada383f/
http://blogs.msdn.com/b/isaac/archive/2007/12/27/latitude-longitude-ordering.aspx
http://www.spatiallyadjusted.com/2007/12/27/microsoft-turns-the-world-right-side-up-again/

-Mike



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