Minutes of Telecon 13 December 2010

Attendees

  • John Schattel (NWS),
  • Chris Little, (UK Met Office),
  • Adrian Custer (Geomatys),
  • Frederic Guillaud (Meteo-France)
  • Marie-Francoise Voidrot (Meteo-France)

Apologies

* Bruce Bannerman (BOM) Time not adapted for Australia.

Proposed Agenda

  1. Update of the plans of work
  2. Update on the works going on via the email list and the twiki on CRSs
  3. Update on the I.E.
  4. Next Telcon

1) Handling of Time :

We have reach a point into the previous teleconfs and meetings where we have decided stand that :
  • TIME shoudl be used for validity time
  • a DIMENSION RUN_BASE_TIME could be used for the RUN (or CYCLE) time of the model
  • DIM_FORECAST_OFFSET doesn't seem to be needed anymore

Issue: not all combinations of TIME/RUN are possible

In Exeter we proposed to define
  • a set of layers for Generic WMS clients only with TIME to offer best product (responsibility of the data provider to select /define his policy) serving past data (dark green line)
  • another set of layers for MO Profile clients using TIME and DIM RUN_BASE_TIME (light green and white dots)

The MO Profile will state that "a TIME default value should be defined by the server. TIME= Current . It is server policy to define how to implement Current "

We then decided to go towards I.E. to test these proposals and the impact on the capabities. (see further the I.E. point)

2) CRSs :

The twiki page : http://external.opengis.org/twiki_public/bin/view/MetOceanDWG/MetCoordinateReferenceSystemDefinition

has been updated by Adrian and I .

Everybody is warmly encouraged to complete the paragraph "Other needed CRS definitions:" if needed.

During the teleconf , we reviewed the CRS needed and already identified as needed and missing into WMS1.3 possibilities by now

  • orthographic : We wondered if it is an approximation os geos projection => Action : Marie-Francoise checks
  • Geos : This projection is defined into the document GCMS 03 "HRIT-LRIT Global Specification". It seems there is a problem of datum on this projection. There is a proj4 definition at : http://spatialreference.org/ref/sr-org/81/ and http://spatialreference.org/ref/sr-org/81/proj4js/, but with an error as it is defined with a WGS4 datum. Maybe this error is volunteer due to the fact that the real datum is specific and the approximation is maybe acceptable. It can be the opportunity to clarify these projections with GCMS. Meteo-France pushes the analysis of this issue or will provide the parameter to define the geos projections for each geostationnary meteorological satellite. Joan says it is possible to add them into the WMS2.0 spec.
  • parametric CRS : Adrian also confirmed there is space into WMS2.0 to define parametric CRS to be able to define a central meridian.
  • PROJ4:"+proj=stere +lat_0=90 +lat_ts=60 +lon_0=0 +k=1 +x_0=0 +y_0=0 +a=6378273 +b=6356889.449 +units=m +no_defs" : identical as parametric CRS above
  • PROJ4:+proj=stere +lat_0=90 +lat_ts=60 +lon_0=10 +k=1 +x_0=0 +y_0=0 +a=6378273 +b=6356889.449 +units=m +no_defs", : identical as parametric CRS above
  • PROJ4:+proj=stere +lat_0=90 +lat_ts=60 +lon_0=20 +k=1 +x_0=0 +y_0=0 +a=6378273 +b=6356889.449 +units=m +no_defs : identical as parametric CRS above
  • Requirement of Polar Stereographic projection with arbitrary base meridian : identical as parametric CRS above
  • ...

Chris took an action to check if there are specific CRSs missing to fulfill aeronautics requirements. He sent an email on the 14th around this action. This email content will be integrated or synthetesized into the twiki page.

We spoke a little bit about the need or not of Compound CRSs. Andrew had reminded by a previous email that the ISO 19111-2 has been made for that. We have identified a need for the following levels : hPa, Meters, PVU, Flight levels, Aeronautical levels (Tropopause level, Jet level, Freezing levels...).

3) I.E.

The next teleconf will focus on this.

On the twiki , the page : http://external.opengis.org/twiki_public/bin/view/MetOceanDWG/MetocWMS_Servers has been made to gather all the locations announced in previous discussions or emails. Some of them don't work : please update them if you wish your server to be used or take them off. John Shattel has updated the references to NWS servers.

Each server has a "more info" page to be completed with informations such as :

contact person or list, including access procedures including status of service, example of getCapabilities, period of availability, data policy, the set of data, publication agreement…

Please complete it before the 3rd of January of possible to feed in the discussions of the next teleconf.

Thank you all for your contributions.

4) Next Telcon
3rd of January 2011 16 UTC - Agenda : I.E.

-- MarieFrancoiseVoidrotMartinez - 16 Dec 2010
Topic revision: r2 - 03 Feb 2011, MarieFrancoiseVoidrotMartinez
 

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