mapserver WMS time and postgis.

[Yewondwossen Assefa]

Denis,

  Sorry for the delay.

  Please enter a bug (WMS Server module) and code contribution and I 
will integrate it in mapserver.

Thanks.

Denis Nadeau wrote:
> Hi,
> 
> I would like to change some of the  code in mappostgis.c to reflect C 
> 5.2 Nearest Value instructions found in  WMS 1.1.1 specifications for 
> "TIME" parameter. 
> http://portal.opengeospatial.org/files/?artifact_id=1081&version=1&format=pdf 
> <http://portal.opengeospatial.org/files/?artifact_id=1081&version=1&format=pdf>
> 
> Here what it says in the WMS 1.1.1 doc.
> 
> "If a request does includes an imprecise dimensional value, and nearest 
> value behavior has been declared, then the server shall compute and send 
> the nearest available value. The value shall be rounded, not merely 
> truncated."
> 
> Right now, mapserver is using date_trunc function to allow the user to 
> specify months, days, hours or minutes.  I think this could be enhanced 
> to get the nearest time value in Postgres.  For example,  NASA GES has 3 
> hourly data.  If the user  specify 2006-09-28T02:00  a blank image is 
> return, the user needs to be exact 2006-09-28T03:00.  Same thing with 
> 10-day data,  2006-09-03 will  return a  blank image.  User have to hit 
> the right date 2006-08-10, 2006-08-20, 2006-08-31, 2006-09-10,.... 
> 
> Example
> Tropical Rain data 3B42_V6_10_DAY:
> http://g0hep12u.ecs.nasa.gov/mapserv-bin/wms_ogc?SERVICE=WMS&VERSION=1.1.1&REQUEST=Getmap&layers=bluemarble,TRMM_3B42_V6_10_DAY&BBOX=-180,-50,180,50&TIME=2005-08-20 
> <http://g0hep12u.ecs.nasa.gov/mapserv-bin/wms_ogc?SERVICE=WMS&VERSION=1.1.1&REQUEST=Getmap&layers=bluemarble,TRMM_3B42_V6_10_DAY&BBOX=-180,-50,180,50&TIME=2005-08-20>
> 
> blank image
> http://g0hep12u.ecs.nasa.gov/mapserv-bin/wms_ogc?SERVICE=WMS&VERSION=1.1.1&REQUEST=Getmap&layers=bluemarble,TRMM_3B42_V6_10_DAY&BBOX=-180,-50,180,50&TIME=2005-08-20T04:00 
> <http://g0hep12u.ecs.nasa.gov/mapserv-bin/wms_ogc?SERVICE=WMS&VERSION=1.1.1&REQUEST=Getmap&layers=bluemarble,TRMM_3B42_V6_10_DAY&BBOX=-180,-50,180,50&TIME=2005-08-20T04:00>
> 
> 
> Let me know if this make sense to you.  I would be happy to contribute 
> some coding for this.
> 
> 
> Denis
> 
> 


-- 
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Assefa Yewondwossen
Software Analyst

Email: assefa at dmsolutions.ca
http://www.dmsolutions.ca/

Phone: (613) 565-5056 (ext 14)
Fax:   (613) 565-0925
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