I've been trying to set up a few timed WMS layers in GeoServer. They're simple enough, of the form


so for every region and date you have some value, e.g. the precipitation in that day.

When I set up the layer without time dimensions, I get a working layer where I can see all my regions (although each of them is present multiple times, once for every corresponding date).

Then, I enable the time dimension, with attribute = DATE and presentation = LIST. When I call GetCapabilities, it really contains something like

<Dimension name="time" default="current" units="ISO8601">

However, when I request GetMap, results vary.

  • with MS SQLServer backend, I get blank image if the type of DATE column is date, but I get the correct map image if it is datetime
  • with PostGis backend, I always get blank image, whether I use date or timestamp

( one day granularity is enough for my list, so to represent 2003-12-31 I'm ok with using any timestamp within that day )

Note that GeoServer considers all of these datatypes compatible with the time dimension and allows the user to set them as the time attribute.

Has anyone encountered such problems? Am I misunderstanding something about the WMS-T?

EDIT: I've recently found out that timestamptz is the type that works with PostGis. Still, why...?