[Mapserver-users] OGC-compliant WMS-server delivering dynamic layers with MS?

[Debbie Pagurek]

It is definitely possible to create a WMS service that can access
lat/long fields from a database.  We are using PHP/Mapscript to do this.
 The php script looks at the name/value pairs in the request and returns
an image.

For example, in the example below, we are passing the name of a given
taxon as the Layer name (Cyanocitta cristata).  The php script then
creates a mapfile on the fly, retrieves the Cyanocitta cristata points
from the database, adds the lat/long coordinates as feature (POINTS) to
the map, creates an image in the format specified in the url request, 
and then returns the image
  $theheader="Location: http://thehost".$image_url;
    Header($theheader);

http://wms1.agr.gc.ca/mapdata/itis/testscript.php?VERSION=1.1.0&REQUEST=GetMap&Layers=Cyanocitta%20cristata&SRS=EPSG:42304&BBOX=-2750560,-936638,3583870,4673120&WIDTH=339&HEIGHT=300&FORMAT=image/png

The one problem we have had with this application is the
GetCapabilities.  We have over 100,000 taxa available for mapping, but
we don't want to generate such a large getcapabilities document that
lists the each taxon as a layer.  So instead we have a 'dummy'
getcapabilities document that is returned from
http://wms1.agr.gc.ca/mapdata/itis/testscript.php?VERSION=1.0.0&REQUEST=GetCapabilities
 This document provides instructions on how to formulate the getmap
request e.g. Layers=Abudefduf or Layers=Cyanocitta cristata.

Some of the WMS viewers that are available out there on the internet
seem to automatically go to the getCapabilities request, even if you
enter a getmap request.  Because of that, there has been some difficulty
using our WMS in some online mapping applications.  That being said,
however, it is very easy to use our getmap requests in Web Map Context
documents that can combine the point distribution maps on top of other
layers.  These web map context documents can be that can be loaded into
applications that handle those types of documents..

Good luck with your work!
Debbie Pagurek


>>> "Frieso ter Haseborg" <ter-haseborg at sf-datentechnik.de> 09/17/03
11:56AM >>>
Hi,

I'm searching for possibilities to use MS for building an
OGC-compliant
WMS-service which creates and serves dynamic layers from data out of
RDBMS. These RDBMS do NOT have any spatial-extensions it's just the
"x,y-coordinate & label-data"-thing. 

So what I want to do: retrieve the coordinates from my databases and
create one or more dynamic layers. I did some experiments with
PHP/MapScript, no major problems so far, that seems to be the easier
part.

The problem comes here: I don't want to create these layers in any
client-app, I want to have these layers served by the mapserver, since
I
have to incorporate other servers e.g. ArcIMS which have to use and
process this layers through OGC-requests. Any ideas?

Are there any possibilities to create dynamic layers from RDBMS e.g.
Sybase ASA, MS SQL Server, Oracle without spatial-extensions I
overlooked, besides doing this in PHP/MapScript?

Are there any hooks or entry-points in the mapserv-cgi to process
customized-operations like creating the mentioned dynamic layers?

Any comment and hint would be appreciated!

TIA,
 
Frieso ter Haseborg
- Software Development - 
 
--

-------------------------------------------------- 
S&F Datentechnik GmbH&Co.KG 
Reimersstr. 41b 
26789 Leer, Germany

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