[OpenLayers-Users] OL display issues.

[Andreas Hocevar]

Nicholas Efremov-Kendall wrote:
> I'm trying to get a simple OL application to  display a mapserver 
> mapfile, but all I get is the grey background for the image, and a the 
> embedded scale bar displaying much smaller linear measurements than 
> the static mapserver file (0.2 vs 16 km). I have specified for the OL 
> map projection to be UTM 32N (Epsg: 22332) and meters for Units. I 
> don't understand why the display coordinated for the mouse position 
> are still LatLon and why the map data won't display. It's reading the 
> mapfile, but I don't know why I won't display the raster or verctor data.
> any suggestions?

You need Mapserver to render layers defined in a mapfile. OpenLayers can 
then request images from Mapserver, but it won't work directly with 
mapfiles. See http://docs.openlayers.org/library/layers.html for layer 
types supported by OpenLayers.

>
> JS CODE
>  map = new OpenLayers.Map('map', { projection: new 
> OpenLayers.Projection("EPSG:22332"),
>                       displayProjection: new 
> OpenLayers.Projection("EPSG:22332"), units: "meters"});
>                  layer = new OpenLayers.Layer.MapServer( "Jerba",
>                          "http://localhost/cgi-bin/mapserv", {map: 
> '/home/mapdata/jerba.map', layers: "satt"} );
>                   map.addLayer(layer);
>                   map.zoomToExtent( new OpenLayers.Bounds (629664.75, 
> 3694383.75, 718556.25, 3770763.75));
>                     map.addControl( new 
> OpenLayers.Control.LayerSwitcher() );
>                 map.addControl( new OpenLayers.Control.MousePosition() );
>                     map.addControl( new 
> OpenLayers.Control.OverviewMap() );
>                     map.addControl( new OpenLayers.Control.ScaleLine() );

You also have to specify a maxExtent for either the map or your layer.

Regards,
Andreas.

-- 
Andreas Hocevar
OpenGeo - http://opengeo.org/
Expert service straight from the developers.