Simple configuration PostgreSQL/MapServer/Openlayers

Sun Mar 11 06:30:54 PDT 2007

Andy,

http://mapserver.gis.umn.edu/docs/howto/wms_server

Have you seen this link? It should help. There are a bunch of Mapserver 
HowTo Docs off the Mapserver Documentation page.

-Steve

Andy Fo wrote:
> Hi,
> Is there anybody out there that can help me with this very simple
> configuration?
> I’m new to WMS and I’m learning about it right now. I’m not completely new
> to programming though; I have experience in C, PL/SQL, MapBasic and a bit
> of JavaScript and HTML. I’m into GIS and used Oracle Spatial with MapInfo
> software at work. I only now started to appreciate open source.
> 
> I decided to go onto practice straight away and opted for the following
> configuration:
> 
> PostgreSQL/PostGIS (this is an excellent db and the documentation is
> impressive!)
> MapServer for rendering images and
> Openlayers as a simple way to interact with the map/information.
> Everything installed locally.
> 
> All I need is some sort of “Hello World” style example, some sort of
> launch pad where I can add or change bit and pieces as I learn. Seeing
> something actually working would give me the confidence to going through
> all the details.
> It should work with this configuration and I would be really grateful if
> someone could help me with this.
> 
> I have loaded some vector data into Postgres, some polylines (or
> linestrings) representing road network. This is referenced to British
> National Grid (BNG) srid: 27700. The table has been spatially indexed.
> 
> Here’s where I can smell some trouble.
> MapServer successfully outputs a png image with the following map file:
> 
> MAP
>   IMAGETYPE      PNG
>   EXTENT         525300 179800 536700 187600
>   SIZE           800 600
>   SHAPEPATH      "/ms4w/apps/TestMaps/FirstTest"
>   IMAGECOLOR     192 192 192
>   UNITS          METERS
>  LAYER
>   CONNECTIONTYPE postgis
>   NAME "tlrn_network"
>   CONNECTION "user=??? password=??? dbname=mapping host=localhost"
>   DATA "wkb_geometry FROM net"
>   STATUS ON
>   TYPE LINE
>   CLASS
>    COLOR 0 0 0
>   END
>   METADATA
>    "WMS_SRS"    "EPSG:BNG"
>   END
>   PROJECTION
>    "init=epsg:27700"
>   END
>  END
> END
> 
> I tested this firefox and the following URL:
> 
> http://localhost/cgi-bin/mapserv.exe?map=/ms4w/apps/TestMaps/FirstTest/tlrn.map&layer=tlrn_network&mode=map
> 
> So far so good, but here’s the trouble:
> 
> <html>
> <head>
> <script src="http://openlayers.org/api/2/OpenLayers.js"></script>
> </head>
> <body>
>   <div style="width:100%; height:100%" id="map"></div>
>   <script defer="defer" type="text/javascript">
>     var mymap = new OpenLayers.Map('map');
>     var mylayer = new OpenLayers.Layer.WMS( "OpenLayers WMS",
>         "http://localhost/cgi-bin/mapserv.exe?",{layers:
> 'tlrn_network',map:'/ms4w/apps/TestMaps/FirstTest/tlrn.map'},{projection:
> "EPSG:BNG"});
>     mymap.addLayer(mylayer);
>     mymap.zoomToMaxExtent();
>   </script>
> </body>
> </html>
> 
> It just doesn’t work. Openlayers kind of attempt to display the image, it
> shows the correct background color. However, instead of my road network,
> it shows the following error message on each tile:
> 
> “MsWMSLoadGetMapParams(): WMS server error. Cannot set new SRS on a map
> that doesn’t have any projection set. Please make sure your mapfile has a
> projection defined at the top level.”
> 
> Well, obviously my map file has no defined projection at top level. It is
> only defined at the layer’s level (and probably wrongly). Whenever I
> attempt to do at the Map top level it seems that things get only worse or
> no change at all.
> When I get rid of the metadata, for example
> #  METADATA
> #   "WMS_SRS"    "EPSG:BNG"
> #  END
> the message changes to:
> “msWMSLoadGetMapParams(): WMS server error. Invalid SRS given : SRS must
> be valid for all requested layers.
> 
> I’m stuck! As I said all I need is something that works and I can use as a
> base. I’ll go away and practice with all this without harassing the entire
> community (well, for a while at least!).
> 
> Many thanks
> 
> Andy