using tile index for serving wms and wcs

[Norman Barker]

-----Original Message-----
From: Miguel Ángel Esbri [mailto:techdlists at yahoo.es]
Sent: Tuesday, December 20, 2005 11:15 AM
To: Norman Barker
Cc: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] using tile index for serving wms and
wcs


Hi Norman,

thanks for your help. I have included a zipped file with the log, the 
getcapabilities of the wms and wcs request, the .map file and the tile 
index that I generated.

regards,

    Miguel Ángel

Norman Barker wrote:

<snip>
>
>I am using a tile index for serving a large number of .tif files so, the 
>layer can be accessed via wms and wcs. When I am using the wms I can 
>access to it without any problem, but when I ask for the getcapabilities 
>of the wcs I get no layer from it.
>
>I have followed some examples that explain how to do this 
>(http://mapserver.gis.umn.edu/docs/howto/WCSServerFormatHowTo), but I 
>still haven't managed to solve this.
>
>thanks in advance,
>   
>       Miguel Ángel
>
><snip>
>

Hi Miguel,

Using a tile index for WCS is slightly different for WCS that WMS with MapServer, quoting Steve Lime from his page (not the WCS Use Cases, but the WCS How To)

'In order to more efficiently support the WCS specification a new tiling scheme has been implemented within MapServer. One that supports spatial sub-setting, but also ad hoc sub-setting based on any attributes found within tile index. In many cases a temporal attribute could be used, but sub-setting is not limited to that case. The new scheme introduces the concept of tile index layers, that is, a separate layer definition is used to describe the tile index dataset. With this we get all the benefits of any MapServer layer, most importantly we can apply MapServer filters to the data. Filters can be defined at runtime using MapServer CGI, MapScript or via the WCS server interface. The syntax for the layer using the index remains unchanged except that the value for TILEINDEX refers to the index layer instead of an external shapefile.'


So you need to define a layer that is the tile index.

LAYER
 NAME 'data_idx'
 DATA '----/index'
 : 
 TYPE TILEINDEX
 :
END

LAYER
  NAME 'data'
  TILEINDEX 'data_idx'
  :
END

By doing this, you actually reduce the size of your mapfile if you are serving a lot of scenes (only one tile index!).

I am really keen to promote the use of WCS, so if you have a couple of sample images that you want set up, I can set them up on an external server here, and you can get the map file when I have finished and we can go over it and update the docs on the MapServer site if there are any glaring omissions.

thanks,

Norman