[Mapserver-users] Mapserver to SVG Demo

[Jeff Hoffmann]

Geoff Anderson wrote:
> I have not worked with WFS yet.  I have prototyped an application that 
> reads  GML polygons into Java2D objects, computes the intersection, 
> writes the result to GML.  XSLT transforms the GML to SVG which is 
> dynamically loaded over Mapserver generated base maps.   It would be 
> great if I could plug WFS into it.

My experience so far with the WFS support in Mapserver hasn't been 
overly positive so far, but I'm just getting into it.  I'm learning 
about WFS (& SVG) along the way so as much as anything, I'm not even 
sure I'm interpreting how it should work correctly much less if it is 
working correctly.  I can seem to generate a single layer OK, but there 
are a couple of things I've run into.  First, in the WFS spec, it looks 
like you can have multiple TYPENAMEs (layers) in one request & I can't 
get it to work.  Also, it seems like the bounding box isn't being used 
correctly (it seems like the whole layer is being retrieved from a 
PostGIS data source & then filtered from there).

> 
> Purely vector SVG is great, but introduces the obvious challenges 
> associated with moving large/massive text files of the net.  

It seems to me that the compressed SVG files end up being pretty 
reasonable in file size (it looks like 75%-80% compression).  Plus, if 
you use something like PNG, the more detailed the image, the poorer the 
compression, so unless you have an image that's hopelessly cluttered, a 
compressed SVG should end up at least a comparable size.  I know that 
the Adobe plugin supports svgz, but I guess that it's just an assumption 
on my part that they all do.  And I haven't even talked about all the 
cool additional features yet...  I'm a bit concerned about using it in 
public sites, though, because of the poor/non-existant support in 
Mozilla/Netscape 7 & scripting issues on the Mac.  I still have to look 
into both of those things more, but what I've heard hasn't been promising.

-- 

Jeff Hoffmann
PropertyKey.com