[mapserver-users] Using MapServer with ERMapper's Image Web Server (IWS)

[Andrew Hallam]

Hi Tyler,

--On Friday, April 12, 2002 10:42 -0700 Tyler Mitchell 
<TMitchell at lignum.com> wrote:

> Is anyone using MapServer with ERMappers IWS?  I see a MapServer demo on
> their site about integrating MapServer with IWS, but I was wondering if
> anyone can tell me how I could add a layer into my map file that would
> grab an image from IWS (I assume using WMS).

I'm writing a WMS 1.0.0 and 1.1.x interface to do this at the moment. It 
will provide a WMS interface to ECW data from Image Web Server and from 
local file. (Windows only at this stage.)

In the meantime, there are two possible approaches:

** Client Side **

The ECW viewer plug-in, in your browser, would request an image from 
MapServer and overlay it on the ECW raster data. All you need to do it 
write some Javascript and tell the plug-in which colour in the MapServer 
image to make transparent.

There are examples of this in the Image Web Server documentation, and you 
can view some working examples at www.earthetc.com.

I wrote a Javascript WMS 1.0.0 library to do this a while ago. If anyone is 
interested I'll see if I can dig it up.

** Server Side **

The usual approach is to run MapServer on Windows and compile it with ECW 
support. That lets you read ECW data from a local file. If you want to use 
Image Web Server (over HTTP) instead of a local ECW file you should be able 
to replace the ECW file path in the map file with an ecwp URL (I haven't 
actually tried this with MapServer but it works fine on my image server).

e.g. Replace "d:\ecwfiles\yourimage.ecw" with 
"ecwp://someserver/ecw/yourimage.ecw"

Note: As previously discussed on this list, MapServer's handling of 24bit 
colour still needs a bit of work so the quality of the output is not 
optimum when reading ECW data.

Regards
Andrew Hallam

Digital Earth Pty Ltd
http://www.digitalearth.com.au