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[Fwd: [Moderator Action] Question about using SVG for map data?]

From: Chris Lilley <chris@w3.org>
Date: Sat, 13 Jan 2001 01:11:36 +0100
Message-ID: <3A5F9D38.CD2D18BE@w3.org>
To: SVG public list <www-svg@w3.org>
Non-member posting.

-- 
Chris

attached mail follows:


Hello,

	If this is the wrong type of question for this forum I apologize.

	I have been experimenting with map data (TIGER, DXF, Shape etc) in SVG, and
have a question regarding the viewport and transforms:

	In mapping it is generally advisable to furnish the feature coordinates in
a known georeferenced coordinate system. This allows client users to do
their own transforms to other georeferenced coordinates possibly matching
data sets they may already be using. Therefore I have created the SVG files
with coordinates in the default system ie Long,Lat or UTM NAD27 meters which
required a flip scale(1.0,-1.0) and a translate in order to center
upside-right in the viewport. This works fine www.cadmaps.com/svg-tiger.htm
, until I add text labels to the polylines which requires a translate of
coordinates to the text insert point, followed by a second flip
scale(1.0,-1.0), followed by whatever rotate is necessary for alignment,
followed by a translate back to viewport. This works but I am beginning to
think there must be an easier way, besides, the textPath on asymmetric paths
will not work? Is there some text element attribute that allows transforms
to apply to text insert points but not to the text glyphs? I am
experimenting using the Adobe SVG plugin 1.0 and the Batik Beta viewer.

	Perhaps my approach is altogether off with attempting to preserve the
original coordinate systems. This will probably also be a problem with
engineering design applications in general since engineers are used to
Cartesian coordinates (ie +y up). I would appreciate any feedback.

	By the way I think SVG is the most exciting thing for engineers since PC
CAD was introduced in the early '80s.

Thanks
Randy George
1-800-627-2923
www.cadmaps.com
Received on Friday, 12 January 2001 19:11:52 GMT

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