[OpenLayers-Users] Coordinates Reversed

[Jerome A. Wendell]

Tom,

Thanks for your reply.  I am using WFS 1.1.0 and and GML 2.  I am using
OpenLayers 2.12, and on the server I am using GeoServer 2.2.4.  The WMS
layer that I am accessing is in shapefile format, and is in EPSG:4326.  The
data, server, etc. are all ours.  The original question that I had was when
the WMS layer is accessed using a select control, the features are returned
in GML format with the longitude first, and then the latitude.  When the
same layer is accessed using a filter to select only features with a
specific attribute value, the features are returned in GML format with the
latitude first, and then the longitude.  I am fairly new to OpenLayers and
GeoServer, so I presumed that I must be doing something wrong for the
coordinates of the same feature to be returned in reverse order.  I will try
using WFS 1.0 and see what happens.

I appreciate the information.

Thanks.

-----Original Message-----
From: openlayers-users-bounces at lists.osgeo.org
[mailto:openlayers-users-bounces at lists.osgeo.org] On Behalf Of Tom Kunicki
Sent: Monday, March 11, 2013 5:14 PM
To: undisclosed-recipients:
Cc: OpenLayers User List
Subject: Re: [OpenLayers-Users] Coordinates Reversed


To help it would be useful to know the WFS version and server-side vendor
and implementation you are attempting to utilize.

The easiest thing would be to use WFS 1.0 with GML2.  You'll (usually) get
back geographic coordinates in [lon, lat] 

The longer gist-of-it-but-skipping-details explanation:

There's some ambiguity as to what the axis ordering should be.
Computer-folk tend to prefer [x, y] or [lon, lat] and this was how the
computer-folk implemented these services for a long time.  The reality is
that the authorities that define the coordinate systems (i.e. the "EPSG" in
"EPSG:4326")  define the proper axis order for coordinates.  As an example
for EPSG:4326 the authority defined axis order is [lat, lon] == [y, x] ==
[north, east].  The purists brought up this discrepancy and in 2009 the OGC
put forth this guidance note:  http://www.ogcnetwork.net/node/491.  What
this says that any specification generated after 2009 (and implementations
of those specifications) must respect the authority defined axis order (i.e.
[lat, long] not [lon, lat]).  Now this is all muddled because vendors have
put forth varying degrees of compliance in the implementations of these
newer services.  There a number of nuances to all of this and it's usually
easier (if possible) to use servi  ces that pre-date the 2009 upheaval
(where everything was in the incorrect, but consistent axis order).

Tom