Accessing images using time dimension.

Dave Weaver dave.weaver at ZEN.CO.UK
Wed May 16 06:39:46 EDT 2007


On 15/05/07, Yewondwossen Assefa <assefa at dmsolutions.ca> wrote:
> Dave Weaver wrote:
> >
> > 1) What am I doing wrong (or not doing at all) ?
> >
>    Do you have your imagery displaying when doing a simple draw map ?
> (either a wms getmap or mapserver cgi). This is to make sure that the
> tile index and the pg layers are set properly.

Forgive my ignorance, but I'm not sure what you mean by a simple draw map.

My current attempted access is via this WMS GetMap call:

http://localhost:8080/cgi-bin/mapserv?map=/home/map/fgs/www/htdocs/maps/postgis2.map&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&amp;amp;LAYERS=world,sat,radar&WIDTH=800&HEIGHT=400&FORMAT=image/png&TRANSPARENT=false&&amp;amp;BBOX=-90,-25,90,85&TIME=2007-05-11T11:00

How do I simplify it to test the tile index and pg layers as you suggest?
 
> > 2) Am I right in thinking the geometry column can be null and the rows
> > will still be considered, depending on image_time ?
> >
>   I think the geometry needs to be valid, each row of geometry should
> normally represent the bbox of the image.

Fair enough. I've tried adding a proper geometry (see my other email in this
thread) to no noticeable effect.

> > 3) Is the duplication of the metadata in the 2 layers above necessary?
> > I've done it this way because that's what's in the example in the "WMS
> > Time Support" document, but do I really need to repeat all this
> > information?
> >
>   The matadata should only be necessary on the tileindex layer.

Makes sense. It would be nice if  the example I mentioned above was adjusted
appropriately then :-)

> > 4) How can I debug this - is there some way I can find out *why* it's
> > not displaying the raster layer? Is there maybe some way to show which
> > time periods it's considering?
> 
>    the wms time in your case ends up setting the filter element on your
> postgis layer to something like :
> "(date_trunc('minute',image_time) = '2007-05-11T11:00:00')" .
>   Assuming that your imagery is displayed without a time request,you can
> manually set the filter element and see if that is working.


It seems unusal to me that there is no logged information from mapserver to
help track down issues like this. I tried adding the "DEBUG ON"  directive
to my map file and specifed a LOG location, but I still see no log.  I
rebuilt following a "./configure [....] --with-debug" and still see no log
file. Most frustrating!  Perhaps I did something wrong there - I will
investigate further.

> > 5) Is there some basic HowTo document that explains what I'm trying to
> > do? (I couldn't find one).
> >
> > Thanks a lot
> > Dave.
> >
> 
> 
> --
> ----------------------------------------------------------------
> 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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