[Chameleon] Does chameleon have a WMS CLIENT?

Paul Spencer pspencer at dmsolutions.ca
Tue Nov 23 11:28:05 EST 2004

Roland ... SRS is spatial reference system, or projection.  All WMS 
servers advertise the SRS that each layer is available in.  In general, 
all layers would be available in the same projections from a single 
server, but this is not a requirement of WMS, esp when cascading.  The 
SRS is a mandatory parameter when requesting a map image from a wms 
server.  The client software must be intelligent enough to request all 
the layers in the same SRS, or the output will be meaningless. 
Unfortunately, not all WMS servers are properly configured to advertise 
all available SRSs ... and some only support a very limited set.  When 
combining data from multiple sources, it is often difficult to get the 
data in the same SRS ... mostly because the data is only appropriate in 
that SRS (for instance, world bathymetry layers might be accessible only 
in a lat/lon projection - epsg:4326) but you may want to show it in a 
projection more suitable for your application's area of interest (in 
Canada, we often use epsg:42304).  In this case, MapServer handles the 
conversion for you.

If you are sure that all the data you want to access is available in a 
common projection (one that you want to use) then a javascript-only 
client may be the best choice for you.

I am curious about your level of knowledge of WMS ... I assumed since 
you were so adamant about needing to use WMS that you would be familiar 
with the basic concepts.  Are you really sure that you must use WMS? 
Are you aware of the pro's and con's?  Seems to me that you may need to 
do some more reading before choosing a client library for your application.


Roland G. wrote:
> Paul Spencer wrote:
>> may be more efficient for just WMS (assuming all WMSs that you want to 
>> access are available in the same SRS).  Chameleon, by using 
> What is a SRS?

|Paul Spencer                           pspencer at dmsolutions.ca   |
|Applications & Software Development                              |
|DM Solutions Group Inc                 http://www.dmsolutions.ca/|

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