Re: Some questions about SVG


At 04:23 PM 1/24/00 +0100, Petra Kalmes wrote:
>As a student of physical Geography presently I acquire my M. Sc. work
>about web mapping and the visualization of two-dimensional geodata. I
>do that in collaboration with Dr. Frank Lochter, project manager at the
>data center of the GFZ in Potsdam, a german research centre.
>The data center supports the GFZ's geoscientists by services like
>www-based catalog service systems and web mapping to enable the access
>and global exchange of spatial information.
>In this connection the data center is very interested in using SVG. It's
>especially my job to try out what functions and possibilities SVG
>And now I've got the following problem: To visualize several german
>administrative districts in svg-format, we've extracted the accordant
>coordinates from an ArcView shape-file and embedded them into a
>svg-file. But now in the
>SVG-Viewer from IBM that we use the most time the districts appear
>mirrored. My question is on the one hand if there's a possibility to
>mirror an object, 

SVG supports arbitrary 2x3 matrix transformations. To mirror about the
Y-axis, you can say:

transform="matrix(-1 0 0 1 0 0)"

>and of the other side if it's possible to visualize
>data in different projections (UTM, Gauß-Krüger etc.).

SVG only supports transformations that are possible using 2x3 matrices. I'm
not familiar with the projections you mention above. My guess is that these
projections would not be possible via 2x3 matrices, in which case you have
to resort to an approach like JavaScript (i.e, perform the math in
JavaScript and modify the SVG DOM to make the picture reflect the projected

>We really support the idea of SVG and I'd be glad to get an answer from
>you soon.
>Petra Kalmes

Incidentally, I recommend that you take a look at the Adobe SVG Viewer at
some point to see how well it addresses your needs.
( The Adobe SVG Viewer works as
a plug-in for Netscape Navigator and Internet Explorer, which is an
advantage in many usage scenarios.

>Petra Kalmes
>Data Center
>GeoForschungsZentrum Potsdam
>Telegrafenberg A3
>14473 Potsdam
>fon. +49-331-288-1694

Received on Monday, 24 January 2000 13:29:45 UTC