Can map server send feature data/vector data to the client?

[Stephen Woodbridge]

Hello Andrea,

In principal based on your description the answer is no; partly for the 
reasons you mentioned, ie: licensing is a potential issue, but more so 
for the volume of data. For example Tiger data for the US is about 18GB 
of vector data. Navteq data for the US and Canada is about 35GB and for 
Europe it is about 53 GB, Topozone has 20+ TB of imagery data online, 
etc. Also, just keeping track of what the client has and needs probably 
consumes more time than you save.

There are 4 potential ways to do this for smaller data sets:
1) mapserver supports Flash swf files and it might be possible to send 
some vector data in the swf file.
2) mapserver supports SVG output (I think?) similar application to Flash
3) mapserver supports WFS which will send some data as GML
4) PDF output might also write vector data it the PDF document for 
better rendering and printing, especially if the document is scaled up 
to poster size.

As you can see these are not really good examples of off loading 
computing to the client. All that said, mapserver is extremely efficient 
at doing as little work as possible to render a map, if it is set up and 
configured correctly. I work for Where2GetIt.com and we serve 100s of 
millions of maps annually from our production cluster and we have 
significant excess capacity.

-Steve

Andrea Edwards wrote:
> Hello
> 
> I was wondering if it was possible in mapserver to send raw vector/feature
> data to the client's web browser?
> 
> In the standard model for internet web mapping applications each pan/zoom
> operation sends a request to the server and a new map is redrawn. I was
> wondering if it was possible to cut down on some of the processing time by
> sending the vector data to the client and then processing the maps on the
> client side.
> 
> I also thought that this might not be possible because of the sheer size of
> the vector data that you would have to send to the client. You would also
> have to make sure the vector data was removed from the client's machine as
> it would violate your licensing agreement for the map data if it was left
> on someone else's machine (well it would mine anyway).
> 
> I was wondering what people's thoughts were on this issue.
> 
> Also does the jbox javca applet process vector data on the client?
> 
> Many thanks for your help
> andrea
>