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
_______________________________________________
postgis-users mailing list
postgis-users@postgis.refractions.net
http://postgis.refractions.net/mailman/listinfo/postgis-users
_______________________________________________
postgis-users mailing list
postgis-users@postgis.refractions.net
http://postgis.refractions.net/mailman/listinfo/postgis-users
