Vector Data and SVG

[Doyon, Jean-Francois]

Hello,

Coincidence ? We've started looking at this ourselves too !

There are a variety of vector formats out there that could be used to
implement
vector-based web mapping technologies. SVG is one ... we were also looking
at
flash (since the swf standard is now open, and there are librairies out
there for it,
and the plug-in is so common),
and VML, and if you REALLY want to potentially do some cool stuff, VRML (For
true spatial representation of data).

The main advantage is that we move CPU intensive work (rendering) from the
server to the client. Also, as someone mentionned, it can make printing a
lot
easier.

A couple of issues that came up is the fact that in some cases the vector
data is
sent "as-is" and that may cause concern for copyright holders. It also
requires a
lot more bandwith.

Given the recent topics brought up here, it seems that the demand is there
for
more varied input and ouput streams from the mapserver. OGR should provide a
nice way top abstract the "input" side of things (Obtaining data, whether it
be from
shapefiles, OSVecDB, SDE, or anything else).

Maybe creating a modular type of interface for mapserver output would be
usefull.
This might allow for a variety of both raster and vector output, from gif's
to SVG.
"Plug-ins" or "modules" could then be developped when new formats or
standards
come out !

One company in spain has been doing interesting work with vector-based web
mapping,
using open standards : http://www.imapper.com

I personally would most definitely enjoy seeing mapserver support OSVecDB,
since not
only is perfomrmance an issue here, but also the fact that managing very
many data sets
and layers can be very cumbersome, and having a centralized RDBMS centric
data storage
solution that is open source would be MOST interesting. SDE is obviously an
option, but
doesn't run on Linux, and I don't think there are SDE client libraires for
Linux as well, are there ?
(To compile Mapserver with SDE support on Linux ?)

My 2 cents. Now I'm gonna go join the OSVecDB mailing list :)

J.F.

> ----------
> From: 	Jim T. Bowen (GAIA Consultants
> Inc.)[SMTP:bowenj at peligroso.gaiaenv.com]
> Sent: 	Wednesday, October 18, 2000 10:02 AM
> To: 	Robert Chavez
> Cc: 	mapserver-users at lists.gis.umn.edu
> Subject: 	Re: Vector Data and SVG
> 
> We have been discussing this issue in shop for some time and feel there
> *is* a need to consider vector formats in web-based mapping solutions. 
> SVG is one format we have begun looking into and looks somewhat
> promising.  Inherently, it seems like it could mesh well with MapServer
> (obviously some significant re-write would be required).  Comments
> Steve?
> 
> One of the major drivers toward a vector-based solution from our
> perspective is our clients' requests to print scalable maps (e.g., rip a
> 36x60 plot on their in-house plotter).
> 
> My $0.02 (CAD)...
> 
> 
> Robert Chavez wrote:
> > 
> > Greetings,
> > 
> > I've been reading a lot about the Scalable Vector Graphics format SVG,
> > most recently in a decent article:  Vector-based Web Cartography:
> Enabler
> > SVG
> > 
> > http://www.carto.net/papers/svg/index_e.html
> > 
> > Is it worth thinking about coming up with a way for mapserver/script to
> > work with SVG?  The above article has some good mapping examples.
> > 
> > I haven't wrapped my brain around the problem yet, so I don't really
> know
> > what kinds of issues this would involve for mapserver and I have more
> > questions than answers: Is it worth thinking about?  Would any benefit
> be
> > derived from using SVG in a web-based GIS environment like mapserver?
> > Where does SVG stand in terms of OpenGIS standards?
> > 
> > Just some thoughts.  Does anyone have any insights on SVG that they
> might
> > want to share?
> > 
> > Rob Chavez
> > Programmer
> > Perseus Project
>