projection s57 maps

[Bart van den Eijnden]

Hi Peter,

did you make a typo in your e-mail or do you really have CONNECTION TYPE 
with the space in there? It should be CONNECTIONTYPE OGR anyway.

Yes, you can have layers in different projections, just specify the 
PROJECTION blocks per layer. I would recommend adding a PROJECTION block 
for your MAP object, which defines the output projection you want from 
Mapserver. Which output projection are you aiming for?

By far the easiest way to deal with projections is by using EPSG codes. 
So for WGS84 you would use:

  PROJECTION
    "init=epsg:4326"
  END
 
And for the Dutch RD system you would use:

  PROJECTION
    "init=epsg:28992"
  END

Check the EPSG file which comes with PROJ, which is the projection 
library Mapserver uses.

Best regards,
Bart

Peter Huis in 't Veld wrote:

> Hello everyone,
>
> I'm exploring the possibilities of mapserver and I'm a bit stuck on 
> the visiualisation of ENC / s57  maps
>
> I use the following script:
>
> SIZE 400 200
> EXTENT  -1000000 195000 365000 7000000
>
> LEGEND
>  STATUS
>  POSITION
>  TRANSPARANT TRUE
> END
>
> WEB
>   TEMPLATE  "path to global.html"
>   IMAGEPATH  "tmp dir"
>   IMAGEURL  "dir"
>   LOG
> END
>
> LAYER
>  NAME s57
>  TYPE POLYGON
>  STATUS DEFAULT
>  CONNECTION TYPE OGR
>  CONNECTION "file name"
>  PROJECTION
>    "proj=tmerc"
>   "ellps=WGS84"
>  END
>
>  CLASS
>       COLOR 247 507 219
>       OUTLINECOLOR  100 100 100
>   END
> END
>
> Requesting this map file using mapserver provides me with in complete 
> maps. In case I user OpenEv I get a complete visualisation.
>
> I've the following questions:
>
>   - What type of projection and Extent should I use. using ogrinfo 
> provides me with:
>
>             - extent (5.8333333, 51.833333) - (6.0333333, 51.90000000)
>             - WGS84 format indiction ( GEOGCS)
>            -  WGS84 , 4326 (AUTHORITY)
>  
>  Furthermore, some more generic questions
>  - Can I have multple layers using distinct projections? (Shapefile 
> stored in a Postgis DB and S57 maps)
>  - Is there a document to understand the projection type and how to 
> deal with them?  (I've already downloaded lots of info and I use the 
> O'reilly WepMapping)
>  - Does the gdal component act differently in OpenEv and Mapserver 
> causing the differences in the result?
>
> I hope these questions can be answered, otherwise I maybe have to be 
> more specific.
>
> thank is advance
>
> Peter
>
>  
>
>


-- 
Bart van den Eijnden
OSGIS, Open Source GIS
http://www.osgis.nl