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[THREDDS #HKN-141488]: SRS status in THREDDS

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  • Subject: [THREDDS #HKN-141488]: SRS status in THREDDS
  • Date: Tue, 27 Jul 2010 11:15:50 -0600
Hi Steve,

> A user wants to know about current SRS support in the THREDDS WCS/WMS 
> services.
> Specifically, he wants to known if SRS 900913 is supported.  Thank you.

I am not familiar with SRS 900913 but from a quick google search [2][3] it 
looks like it is a pseudo Mercator projection that uses "spherical development" 
[4] and is used by some popular tools (google maps and such). At some point it 
was adopted as an EPSG CRS. At first as EPSG:3785 which has since been 
deprecated in favor of EPSG:3857 "WGS 84 / Pseudo-Mercator".

It is not currently supported by the netCDF-java library which is used by the 
TDS to read data. This means you can't currently use the TDS to serve data that 
is stored in this CRS.

It is, on the other hand, supported by GeoToolkit [1] which is used by the 
ncWMS code to generate the WMS images. However, I have not seen it listed in 
any WMS GetCapabilities documents. I will check if and how the list of CRS 
supported by the TDS WMS can be configured and get back to you.

> Steve Baum
> Texas A&M Dept. of Oceanography


Ethan

[1] http://jira.geotoolkit.org/browse/GEOTK-33

[2] 
http://www.listware.net/201007/openlayers-users/66188-openlayers-users-sphericalmercator-and-srs-aliases-epsg900913-epsg3857-epsg3785-epsg102113.html

[3] http://osgeo-org.1803224.n2.nabble.com/EPSG-3785-td3781768.html#a3781768

[4] EPSG code table:

    "Uses spherical development. Relative to an ellipsoidal development
    errors of up to 800 metres in position and 0.7% in scale may arise.
    Some applications call this WGS 84. It is not a recognised geodetic
    system: see WGS 84 / World Mercator (CRS code 3395)"

Ticket Details
===================
Ticket ID: HKN-141488
Department: Support THREDDS
Priority: Critical
Status: Open