Scott,
For anything other than EPSG:4326 or the Google spherical mercator
projection, OpenLayers uses Proj4js http://trac.osgeo.org/proj4js/ to
handle coordinate conversion between projections, and that uses the
PROJ.4 format for initializing projection parameters, typically based on
looking those up based on the EPSG code.
So if you set your BaseLayer in OpenLayers to have a projection option
with a value of "EPSG:1234" it will internally create the required
projection handling objects to transform coordinates. In your
application, you can either include a projection definition directly as in:
Proj4js.defs["EPSG:1234"]="+title=LAMB sud france +proj=lcc +lat_1=44.1
+lat_0=44.1 +lon_0=0 +k_0=0.999877499
+x_0=600000 +y_0=200000 +a=6378249.2
+b=6356515 +towgs84=-168,-60,320,0,0,0,0 +pm=paris +units=m";
or you can have it looks those up automatically from spatialreference.org.
Mike
Scott hameister wrote:
I don't see anything in openlayers that lets you input a custom Projection?
MGCoordinate looks like it has the ability to poull all the required
Ellipsoid, units, blah blah blah out, but how do I say if ConvertWkttoEPSG
is null Send these custom parameters into Openlayers to create a new
projection...That confuses me.
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Jason Birch
Sent: Wednesday, October 07, 2009 2:49 PM
To: MapGuide Users Mail List
Subject: Re: [mapguide-users] Fusion and Open layers Coordinate systems
I don't think doing cs-map in js would be practical, but wkt parsing
in proj4js sure would be nice...
On 2009-10-07, Mike Adair <[email protected]> wrote:
It's a shame MapGuide doesn't use EPSG codes :-)
OpenLayers applications typically would use Proj4js to do client side
transformations which is based on PROJ.4 which can use EPSG codes and/or
custom initialization parameters. I haven't heard of anyone converting
CS-Map to Javascript.
Mike
Scott hameister wrote:
It's a shame OpenLayers doesn't use mentor/CS-Map...I thought I read
somewhere that it was going to? Anyone?
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Jason Birch
Sent: Wednesday, October 07, 2009 11:28 AM
To: MapGuide Users Mail List
Subject: Re: [mapguide-users] Fusion and Open layers Coordinate systems
I know this is neither here nor there, but I believe there are many
valid projections that do not have EPSG codes. Defaulting to LL when
many "non-standard" CS are liner-units-based may not be the best
approach. Would it not be possible to disable coordinate transforms if
there is no code available?
Jason
On 2009-10-07, Mike Adair <[email protected]> wrote:
I'm currently working on a patch to retrieve the projection info from
the map definition for MapGuide. The problem is that MG uses WKT and
OpenLayers/Fusion uses EPSG codes and MG doesn't always have an EPSG/WKT
mapping available. So I will be implementing this so that if MG returns
a valid EPSG code it will use that, otherwise it will take a value from
the ApplicationDefinition file, and if there still isn't an EPSG code
available then the projection will be set to the OpenLayers default of
EPSG:4326.
Mike
Flipper wrote:
Im trying my hand at some Open Layers programming. I'm trying to set
the
maps
Coordinate system to match Mapguides, So I decided to peek into
Fusion....
One thing for the life of me I can't find is where fusion sets the
OpenLayer
Maps Coordinate system. I know Open layers uses Proj 4, and Mapguide
Can
use
both cs-map and Proj4...I know how to get the coordinate system
Description
out of Mapguide...But how do I push it back into OpenLayers Using my
PROJCS
system...
Or worded Much simpler...How/Where does Fusion do this to
openLayers...I
want this to work on anymap...so I don't want to hard code a EPSG code
into
it, and several users will have Non PROJ4 coordinate systems, like
Local
County Coordinate systems that CS-MAP allows them to use...
ANYONE?
--
Michael Adair
Senior Software Architect
DM Solutions Group Inc.
Office: (613) 565-5056 x26
[email protected]
http://www.dmsolutions.ca
http://research.dmsolutions.ca
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--
Michael Adair
Senior Software Architect
DM Solutions Group Inc.
Office: (613) 565-5056 x26
[email protected]
http://www.dmsolutions.ca
http://research.dmsolutions.ca
_______________________________________________
mapguide-users mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/mapguide-users
_______________________________________________
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[email protected]
http://lists.osgeo.org/mailman/listinfo/mapguide-users
_______________________________________________
mapguide-users mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/mapguide-users
--
Michael Adair
Senior Software Architect
DM Solutions Group Inc.
Office: (613) 565-5056 x26
[email protected]
http://www.dmsolutions.ca
http://research.dmsolutions.ca
_______________________________________________
mapguide-users mailing list
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