[OpenLayers-Users] [Geoserver-users] wfs, state plane, and spherical mercator

[Tim Schaub]

Hey-

As Andrea may have already responded (on the GeoServer list), the WFS 
1.0 spec doesn't account for reprojection.  This came out with WFS 1.1. 
  However, GeoServer supports reprojection for both.

The OpenLayers.Layer.WFS layer is not specifically tied to either 
version (and it uses a GML parser that is not specifically GML 2 or 3).

To target a specific version of WFS, use a vector layer with the 
appropriate WFS protocol.

For example:
http://openlayers.org/dev/examples/wfs-protocol-transactions.html

Incidentally, if you set the layer projection to something different 
than the map projection, your geometries will be transformed client side 
  (assuming that you have proj4js or are doing geographic <-> spherical 
mercator).

Tim

David Hollema wrote:
> After some debugging, I figured out some of the problem.  It's due to
> the axis order spec in WFS 1.0 versus WFS 1.1.  On the GML feature
> geometry in my app, originally x was assigned the latitude and y was
> assigned the longitude.  I changed my WFS version in the
> GetFeatureRequest to WMS 1.0 from 1.1 and it works!  Next question is
> how do I specify that WFS version in the OpenLayers.WFS constructor?  I
> tried the same syntax as in my GetFeatureRequest params with no success.
> 
> David A. Hollema
> GIS Analyst
>  
> United Power, Inc.
> 
> -----Original Message-----
> From: users-bounces at openlayers.org [mailto:users-bounces at openlayers.org]
> On Behalf Of David Hollema
> Sent: Wednesday, April 08, 2009 12:48 PM
> To: Andrea Aime
> Cc: users at openlayers.org; geoserver-users at lists.sourceforge.net
> Subject: Re: [OpenLayers-Users] [Geoserver-users] wfs, state plane,and
> spherical mercator
> 
> Here is my code.  WMS reprojects fine b/c my understanding is geoserver
> receives the base map projection (900913) and reprojects accordingly.  I
> would figure that geoserver would do the same thing to the WFS but it
> doesn't.  My SRS handling in geoserver is set to force declared (default
> setting) and my declared is correct, 2231 in this case.  For WMS, it's
> not even necessary to set the srs in the layer constructor b/c geoserver
> just figures it out.
> 
> It's important to note that I even tried with my source data in 4326
> (lat/long) and WMS still worked fine but WFS fails.  It doesn't seem to
> be due to State Plane issues but it's more fundamental than that.
> 
> 				var bounds = new OpenLayers.Bounds
> (-20037508.34, -20037508.34, 20037508.34, 20037508.34);
> 				var options2 = {
>                     units: 'm',
> 					projection: 'EPSG:900913',
> 					maxExtent: bounds
>                 };
> 				format = 'image/gif';
> 
> 				map2 = new OpenLayers.Map('map2',
> options2);
> 				
> 				velayer = new
> OpenLayers.Layer.VirtualEarth( "VE",
> 				{ 'type': VEMapStyle.Roads,
> 'sphericalMercator': true});
> 				
> 				layerWMS = new OpenLayers.Layer.WMS(
> "Joint Use Photos",
>                     "http://upigis:8080/geoserver/wms", 
> 					 {layers: 'sde:jointusepicture',
> 						format: format,
> 						transparent: true
> 						},
> 						{opacity: 1.0,
> isBaseLayer: false, 'singleTile': true
> 						});
> 							
> 				layerWFS = new OpenLayers.Layer.WFS(
> "Joint Use Photos WFS",
>                     "http://upigis:8080/geoserver/wfs", 
> 					{
> 					typename:
> "sde:jointusepicture"},
> 					{extractAttributes: true}
> 					);
> 
> David A. Hollema
> GIS Analyst
>  
> United Power, Inc.
> 
> -----Original Message-----
> From: users-bounces at openlayers.org [mailto:users-bounces at openlayers.org]
> On Behalf Of Andrea Aime
> Sent: Tuesday, April 07, 2009 1:36 AM
> To: David Hollema
> Cc: users at openlayers.org; geoserver-users at lists.sourceforge.net
> Subject: Re: [OpenLayers-Users] [Geoserver-users] wfs, state plane,and
> spherical mercator
> 
> David Hollema ha scritto:
>> Here's my dilemma.  I have a map with projection defined as spherical 
>> Mercator, EPSG 900913.  I have a geoserver WMS layer whose native 
>> projection is state plane Colorado north (EPSG 2231).  With help from 
>> the lists, I'm able to overlay the WMS fine on a Virtual Earth map.  
>> When I add a new WFS layer (pointing at the same geoserver data) using
> 
>> similar constructor as the WMS, the WFS layer does not overlay fine, 
>> it's shifted way off.  That's problem 1.  I can't figure out how to
> get 
>> the WFS to overlay.
> 
> Please share the request you're making. The WFS and WMS reprojection
> syntaxes are not equal. Also, what is the SRS handling you chose
> in your feature type configuration?
> 
>> Next question.  I want to recenter the map based on a feature created 
>> from a separate WFS request.   I use OL.Format.GML and the read method
> 
>> to create a new feature from the responseXML.  When I look at the 
>> geometry of the point feature, the x,y cords are in the native 
>> coordinates.  I tried point.transform("EPSG:2231","EPSG:900913") but
> the 
>> transformation never works properly.  All the examples I see go from 
>> 4326 to 900913.  My data are in State Plane.  I would expect that the 
>> underlying transformation library could handle this transformation but
> 
>> maybe not?
> 
> You can also have GeoServer do the reprojection for you. You just
> have to add &srsName=EPSG:900913 to your request, keeping the eventual
> bbox in 2231, or have the bbox in 900913 too, but state it explicitly
> with &bbox=x0,y0,x1,y1,EPSG:900913
> 
> Cheers
> Andrea
> 


-- 
Tim Schaub
OpenGeo - http://opengeo.org
Expert service straight from the developers.