Accessing images using time dimension.

[Dave Weaver]

On 18/05/07, Yewondwossen Assefa <assefa at dmsolutions.ca> wrote:

> Regarding the wms_time* parameters, they are only needed on the raster
> layer so the doc is good.

Ah ok. My mapfile has been adjusted appropriately (with no obvious effect).

>   do you build mapserver yourself ? if that is the case, you could add
> the folowing lines at the end of function msWMSGetMap in mapwms.c
> 
  --- <snip> ---
Done.

>   If the map is in debug mode and that the web element imagepath is set
> properly, this will generate the map resulting map file after all wms
> parameters are treated.  This will allow you to see if/what is the
> FILTER element that is set re. your time request.
> 
> Let me know, and If this helps and I will add this to mapserver repository.

Well it generated a map file (2 actually, identical apart from filename)
with a lot more information in it than my original. These are the relevant
layers from this bigger map file:

  LAYER
      METADATA
        "wms_timeextent"        "2007-01-01/2007-12-31"
        "wms_timedefault"       "2007-05-11T11:00:00Z"
        "wms_title"     "Satellite"
      END
    NAME "sat"
    PROJECTION
      "init=epsg:4326"
    END
    SIZEUNITS PIXELS
    STATUS ON
    TILEINDEX "time_idx"
    TILEITEM "image_path"
    TOLERANCEUNITS PIXELS
    TYPE RASTER
    UNITS METERS
  END

  LAYER
    CONNECTION "dbname=map host=localhost"
    CONNECTIONTYPE POSTGIS
    DATA "the_geom from satellite using unique oid using srid = 4326"
      METADATA
        "wms_srs"       "EPSG:4326"
        "wms_timeitem"  "image_time"
        "wms_title"     "time_index"
      END
    NAME "time_idx"
    SIZEUNITS PIXELS
    STATUS OFF
    TOLERANCEUNITS PIXELS
    TYPE POLYGON
    UNITS METERS
  END

As you can see there was no FILTER element anywhere.
 I'm a bit stuck as to what to look at next...

To summarise where things are right now:
My relevant layers are defined thus:

  LAYER
    NAME	    "time_idx"
    TYPE	    POLYGON
    STATUS	    ON
#    FILTER "(date_trunc('minute',image_time) = '2007-05-11T11:00:00')"
    CONNECTIONTYPE  POSTGIS
    CONNECTION	    "dbname=map host=localhost"
    DATA	    "the_geom from satellite using unique oid using srid = 4326"
    METADATA
	"wms_title"	    "time_index"
        "wms_srs"	    "EPSG:4326"
        "wms_timeitem"	    "image_time" #a column in postgis table of type
timestamp
    END
  END

  LAYER
    NAME    "sat"
    STATUS  ON
    TYPE    RASTER
    METADATA
	"wms_title"	    "Satellite"
        "wms_timeextent"    "2007-01-01/2007-12-31"
        "wms_timedefault"   "2007-05-11T11:00:00Z"
    END
    PROJECTION
      "init=epsg:4326"
    END
    TILEINDEX "time_idx"	# Layer name containing time index
    TILEITEM  "image_path"	# DB column containing path to image
  END

There are 2 images in the satellite table:

map=> select image_path, image_time from satellite;
                     image_path                      |     image_time
-----------------------------------------------------+---------------------
 /home/map/fgs/www/htdocs/maps/images/sat2.tiff      | 2007-05-11 11:00:00
 /home/map/fgs/www/htdocs/maps/images/yesterday.tiff | 2007-05-11 10:00:00
(2 rows)

and my URL looks like this:

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

However, despite both the TIME in the URL and the wms_timedefault values
showing 11:00, I can only ever see the 10:00 image

If I use this URL instead:

http://localhost:8080/cgi-bin/mapserv?map=/home/map/fgs/www/htdocs/maps/time.map&mode=map&layers=sat

And enable the FILTER line in the time_idx layer to select the 11:00 image,
 I can see it. I just can't seem to get it working using a WMS request. Most
frustrating!

Dave.