[postgis-users] ST_Transform troubles

[Frans Knibbe]

On 2011-06-27 12:44, Mike Toews wrote:
> 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.
As far as I know, I am not disagreeing with any OGC standard. This is 
about PostGIS disagreeing with the EPSG standard, which it uses.
>   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.
My primary concern is not with human readability, but with automated 
processing by computers. A computer only knows what it is being told. 
How is it to know that the coordinates are switched if it is being told 
that the SRS used is defined by an EPSG specification that uses 
latitude-longitude?
> 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/
Thanks, it is interesting read.

I think it is perfectly all right to always use the same axis order for 
all coordinates. But in that case you can not state that you are using 
EPSG definitions, you will have to use some other system of describing 
coordinate reference systems.
> -Mike
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