Re: [thredds] Albers or LCC supported as a WMS projection on the TDS?

Ack! Sorry about that. I'm always stumbling over the various types of
EPSG codes.

Yes, the Albers and LLC EPSG codes you gave are for particular types of
projections, in EPSG aka "coordinate operations methods". From which can
be built particular "coordinate operations" (which I assume have
specific parameter values though I'm having trouble finding them in the
database). And from there, the coordinate reference systems.

My understanding is that the file (in epsg-wkt.jar) is
used in TDS 4.2 but not in TDS 4.3 (GeoToolkit 3.04 vs 3.17). The one in
TDS 4.3 should be newer and a more complete list of EPSG CRSs. So, once
you decide which EPSG CRS codes you want to use, I suspect requests for
them will work without changes in TDS 4.3 but may need the additions
Marcos mentions below. On the other hand, it appears that the file in TDS 4.2 already contains a WKT for CRS 2205 and
I suspect it contains other Albers and LLC based CRSs as well.

If that all works, another fun part is figuring out for each CRS the
valid values of the bounding box corners.


On 10/17/2012 3:24 PM, Marcos Hermida wrote:
> Hi Rich,
> to define either a Lambert Conformal Projection or Albers Equals Area
> you need to provide a set of parameters (standards parallels, central
> meridians, northing, easting...) so there are whole family of LCC and
> Albers projections that you can use. Here you can see some well defined
> ones, with their EPSG codes:
> Albers:
> LCC:
> If you want to use some of them all you have to do is add the OGC WKT to
> the epsg database that is used by ncWMS/THREDDS. That database is the
> file that lives in the epsg-wkt.jar and those are the
> actual projections supported by the ncWMS/THREDDS.
> So, for instance, if you want to add the  Lambert Conic Conformal 2SP:
> NAD83 / Massachusetts Island
> ( you need to add to the
> this OGC WKT:
> with its EPSG code. It
> would look like something like this:
> 2250=PROJCS["NAD83 / Massachusetts Island
> (ftUS)",GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHEROID["GRS
> 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","6269"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4269"]],UNIT["US
> survey
> foot",0.3048006096012192,AUTHORITY["EPSG","9003"]],PROJECTION["Lambert_Conformal_Conic_2SP"],PARAMETER["standard_parallel_1",41.48333333333333],PARAMETER["standard_parallel_2",41.28333333333333],PARAMETER["latitude_of_origin",41],PARAMETER["central_meridian",-70.5],PARAMETER["false_easting",1640416.667],PARAMETER["false_northing",0],AUTHORITY["EPSG","2250"],AXIS["X",EAST],AXIS["Y",NORTH]]
> Cheers!
> On 10/17/2012 11:53 AM, Rich Signell wrote:
>> Ethan,
>> That's great that Albers, LCC and others should work with TDS 4.3 WMS.
>> That means it should work on:
>> which is at TDS 4.3.15.
>> So on that server, I can get this WMS request to work using EPSG:4326:
>> But I can't get anything else to work.
>> Can you provide a modified version of the above request that works for
>> Albers (EPSG:9822) or LCC (EPSG:9802)
>> -Rich
>> On Wed, Oct 17, 2012 at 11:55 AM, Ethan Davis
>> <edavis@xxxxxxxxxxxxxxxx> wrote:
>>> Hi Rich,
>>> Even if a CRS is not listed, both ncWMS and TDS WMS can handle requests
>>> for any CRS supported by the underlying GeoToolkit library. The CRS
>>> database in TDS 4.2 does not contain EPSG CRS 9822 or 9802. However,
>>> they should both be available in TDS 4.3. So, if you are trying this on
>>> a TDS 4.3, you can just give it a try.
>>> As for the WMS GetCapabilities CRS list, it is currently not user
>>> configurable. For TDS 4.3 it would simply be a matter of a minor code
>>> change (adding the two EPSG numbers to a list) and then rebuilding. It
>>> is a bit more work in TDS 4.2, but not much harder, along with adding
>>> the EPSG number to a list, we would need a WKT for each of the new
>>> projections. (The CRS WKT needs to be in a form the GeoToolkit can
>>> read.)
>>> We've kept the list to a minimum because in earlier versions we listed
>>> all available projections and the list got quite large.
>>> Are you using TDS 4.3? Do you need these CRS to be in the list or is
>>> being able to request them enough?
>>> Cheers,
>>> Ethan
>>> On 10/17/2012 8:17 AM, Rich Signell wrote:
>>>> TDS folks,
>>>> What would it take to get Albers or LCC supported as a projection on
>>>> the TDS WMS?
>>>> According to the WMS getCapabilities (for example:
>>>> the supported projections are:
>>>> <Title>Motherlode TDS</Title>
>>>> <CRS>EPSG:4326</CRS>
>>>> <CRS>CRS:84</CRS>
>>>> <CRS>EPSG:41001</CRS>
>>>> <CRS>EPSG:3857</CRS>
>>>> <CRS>EPSG:27700</CRS>
>>>> <CRS>EPSG:3408</CRS>
>>>> <CRS>EPSG:3409</CRS>
>>>> <CRS>EPSG:32661</CRS>
>>>> <CRS>EPSG:32761</CRS>
>>>> Okay, so we don't see Albers Equal Area (EPSG:9822) or Lambert
>>>> Conformal
>>>> Conic 2SP (EPSG:9802) on the list.
>>>> But  TDS WMS is based on ncWMS, and on the ncWMS FAQ at:
>>>> it says that ncWMS "can produce images in any projection that is
>>>> supported by the GeoTools library".
>>>> And it appears that GeoTools can support both Albers and LCC:
>>>> So would it be straightforward (or perhaps even easy) to allow the TDS
>>>> WMS to support these?
>>>> Thanks,
>>>> Rich
>>> -- 
>>> Ethan Davis                                       UCAR Unidata Program
>>> edavis@xxxxxxxxxxxxxxxx          
>>> _______________________________________________
>>> thredds mailing list
>>> thredds@xxxxxxxxxxxxxxxx
>>> For list information or to unsubscribe,  visit:

Ethan Davis                                       UCAR Unidata Program

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