wms layer zoom question

[Daniel Morissette]

Arnold, Micheal B. wrote:
> I am having some difficulty with a WMS layer.  I am retrieving topo maps
> from teraserver.  I have added the minvalue entry to my mapfile so that
> I don't get errors if someone tries to zoom in too far.  My problem is
> that these topo maps are only being displayed at a very specific scale.
> If someone zooms out at all, the topo will not display.  I don't get any
> error messages, but that layer isn't shown at all.  I tried messing
> around with MAXSCALE, but couldn't get it to work.  I will paste the
> layer definition below.  Thanks in advance for any suggestions.
>

If I understand your problem correctly, you'd like the layer to show up
as you zoom out even if the remote WMS server doesn't allow returning
the data at that scale, am I right?

Using MINSCALE/MAXSCALE is the right way to indicate to MapServer that
the remote server doesn't want to return a valid image outside of that
scale range, but unfortunately there is currently no way to tell
MapServer that you'd like to still get an image out of those scales.

One possible way to do this would be to have MapServer produce a GetMap
request internally at a resolution that the remote server will accept
(by using fake width/height), and then resample the image it gets from
terraserver internally... that's not supported at the moment. You could
always file that as an enhancement in bugzilla, ya never know.

Daniel
--
------------------------------------------------------------
  Daniel Morissette               dmorissette at dmsolutions.ca
  DM Solutions Group              http://www.dmsolutions.ca/
------------------------------------------------------------