[Geomoose-users] using Google layers as background

[Brent Fraser]

Yes it is for warping.

The services tend not to be very tolerant of the data coordinate system 
not being the same as the display coordinate system

Best Regards,
Brent Fraser


On 4/15/2011 3:01 PM, John Callahan wrote:
> Thanks Brent.  EPSG:3875 it is.  So the map-source projection 
> parameter in the mapbook file is for warping the mapserver output to 
> fit the display coordinates.  Is that correct?  I agree that the 
> server should output maps in the srs requested and not allow any 
> client-side reprojection.  All of my WMS services support both my 
> local srs and the various google flavors.
>
> I was looking at both the the GeoMoose demos and noticed in the web 
> mercator demo, services such as identify and select are not present.  
> Will those types of services not work with web mercator?
>
> - John
>
> ***********************************
> John Callahan, Research Scientist
> Delaware Geological Survey
> University of Delaware
> URL: http://www.dgs.udel.edu
> *******************************
>
>
> On Fri, Apr 15, 2011 at 4:48 PM, Brent Fraser <bfraser at geoanalytic.com 
> <mailto:bfraser at geoanalytic.com>> wrote:
>
>     John,
>
>     1)  Technically they describe the same coordinate system, but 3785
>     is deprecated and replaced by 3875 as the "official" EPSG code. 
>     900913 was the original, "user defined" (aka non-offical) code so
>     has been in use longer (and some systems may not have adopted the
>     official code yet).  So go with 3875 if possible, but you could
>     use 900913 if necessary.
>
>     2)  You should demand(!) that the WMS servers serve up the data in
>     your display coordinate system (it off-loads the re-projection to
>     the servers)., but if they don't advertise that they support it,
>     you could get GeoMOOSE to warp it on the fly by including a
>     projection='EPSG:4326' option in the <map-source> tag.  Be warned
>     that is only does a warp and the layers will not line up as you
>     zoom out.  The solution is to set up mapserver to act as a WMS
>     client, do the reprojection and serve the result in your
>     coordinates system of choice (e.g. 3875).
>
>     3).  Correct.  And add a PROJECTION block to the LAYER so
>     mapserver knows which coordinate system they are in.
>
>     Best Regards,
>     Brent Fraser
>
>
>     On 4/15/2011 1:25 PM, John Callahan wrote:
>>     I'm creating a GeoMoose application that will use the various
>>     Google tile layers as backgrounds.  (I originally created a basic
>>     app in my local state plane projection but then realized that the
>>     Google-like backgrounds are critical.)   I've downloaded the Web
>>     Mercator demo and am looking at
>>     http://geomoose.org/howto/commercial_layers.html for guidance. 
>>     As I go through this, a few quick questions:
>>
>>     1) Should I use EPSG:3857, EPSG:3785 or EPSG:900913?  Or does it
>>     matter as long as Proj4 supports it and there's a corresponding
>>     file in proj4js\lib\defs
>>
>>     2) In the mapbook file, should all the data sources (nearly all
>>     of WMS type) have the same projection attribute, such as
>>     projection="EPSG:3857"?
>>
>>     3) Just to confirm, my raw data files do not need to be in the
>>     "web mercator" projection, only the MAP Projection and Extent
>>     parameters in the map files, correct?
>>
>>
>>     - John
>>
>>     ***********************************
>>     John Callahan, Research Scientist
>>     Delaware Geological Survey
>>     University of Delaware
>>     URL: http://www.dgs.udel.edu
>>     *******************************
>>
>>
>>     ------------------------------------------------------------------------------
>>     Benefiting from Server Virtualization: Beyond Initial Workload
>>     Consolidation -- Increasing the use of server virtualization is a top
>>     priority.Virtualization can reduce costs, simplify management, and improve
>>     application availability and disaster protection. Learn more about boosting
>>     the value of server virtualization.http://p.sf.net/sfu/vmware-sfdev2dev
>>
>>
>>     _______________________________________________
>>     Geomoose-users mailing list
>>     Geomoose-users at lists.sourceforge.net  <mailto:Geomoose-users at lists.sourceforge.net>
>>     https://lists.sourceforge.net/lists/listinfo/geomoose-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/geomoose-users/attachments/20110415/4fbf13eb/attachment.html