[OpenLayers-Dev] WMS, Mapserver and OpenLayers

[Richard Duivenvoorde]

Hey Bradley,
is your mapserver configuration ok? I would say: install qgis 
(www.qgis.org). This gives you an easy and alternative way to look at 
wms-layers. Just give it the url of your mapserver and the name of your 
mapfile and it will either show you the layers (and projections) which 
you defined in your mapfile or an error.
If that is working, I would try to set up an WMS.Untiled layer first. 
Using firefox and the firebug extension you can see exactly the url's 
that OL is firing at mapserver then. You can see what bbox and srs (aka 
projection) is asked from mapserver then.

I'm working with projected layers also, eg:

map = new OpenLayers.Map('map',  {
      'projection':'EPSG:28992',
      'units':'m',
      'maxExtent':new OpenLayers.Bounds(-20000,300000,300000,650000),
      'resolutions':[1, 2.5, 5, 10, 30, 50, 100, 175, 256, 512],
      'controls':[],  // empty controls om te zorgen dat er NIKS staat
      'theme':null    // empty theme to be able to override
});
// not tiled no cache
xxlayer = new OpenLayers.Layer.WMS.Untiled( "xx", 
"yourserver?map=mymapfile.map", {layers: 'a,b,c', FORMAT:'png'}, 
{ratio:1, units:'meters'} );

If all that is working, you can make it a tiled server and see if there 
is a problem.

About poor quality: are you showing raster or vector data? If raster: 
are you using the right resolutions for your layers? You can do a lot of 
tweaking in the mapserver mapfile (anti aliassing etc).

White screens: be aware of caching of image data in your browser/proxy! 
See if qgis is also giving white screens, if so: looks like an 
mapserver/projection problem.

Hope this is of any help

Richard Duivenvoorde



Bradley Mclain wrote:
> What I am trying to do is import content from my mapserver into OpenLayers.
> 
> I am starting to think from experimentation that the problem has 
> something to do with my projection. If I do not give a projection in my 
> layer definition in OpenLayers and rely simply on the projections given 
> in my mapfile I get a projection error. If i do specify one I simply get 
> a white screen.
> 
> Now i have checked my projection details in proj4 and I am 99% sure they 
> are correct but they are not very standard values, maybe OpenLayers does 
> not support them. Value is EPSG:28355
> 
> I tried again to manually import the data using the mapserver layer 
> option and had some success. The layers actually displayed, which is the 
> best result I've had so far. However there is still a problem, they are 
> rather poor quality and the tiles to not align for some reason.
> 
> 
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