Even data that is not georeferenced has some sort of projection being it
0,0 for the lower left corner and 600,600 for the upper right. So you
should be able to put that in Mapserver with a self created projection
(1). Problems arise when you want to combine your maps with for instance
satellite imagery because in that case you will need transformations to
do the matching, and for transformations you need parameters to convert
one projection to another (2). A quick and dirty solution for (2) would
be to create images and georeference them manually with a GIS. qGIS has
a nice georeferencing plugin that will help you in that process.
As you state in (2) "Mapserver requires a mapfile like a SHP"; that
assumption is wrong. A mapfile is a metafile and in that way more like
a mapinfo wor file (workspace, I don't know the equivalent for esri)
which has the great possibility to create meta descriptions for layers
of an (almost) unlimited amount of known GIS sources.
So, the most important think to ask yourself is:
- Am I going to combine my SVG data source with layers that are
georeferenced?
Because then you have some extra work at hand, but using mapserver to
host your data is always an option.
Kind regards,
Milo van der Linden
Jeremy Short wrote:
The original data is stored in SVG and it is not georeferenced. It is
a collection of hand-rendered maps in Inkscape, an SVG editor, with
geographical measuring units like latitude or longitude.
We wanted to stay away from serving up SVG because Firefox supports
SVG but not IE and we didn't want to force people to have to install a
plugin. I tried the link (http://www.carto.net/williams/yosemite/) and
it looks good but it looks like the plugin is needed for IE.
Any ideas for non-georeferenced SVG/PNG source files to serve up PNG
files which can be used as a base layer for a map? Can I even use a
non-georeferenced SVG/PNG with Mapserver?
Andreas Neumann wrote:
So, if I understand you correctly, your original map data is stored
in SVG files.
In that case you can use Apache Batik to render into georeferenced
PNG files (if your SVG data is georeferenced). You can trigger this
rasterization process whenever there was a change in the SVG data.
This georeferenced raster data can be fed into UMN Mapserver for fast
delivery. My guess is, while the quality of the Apache Batik
rendering process is excellent, it won't be as fast as the UMN
Mapserver, when delivering maps.
Alternatively, you can consider to serve the SVG data directly,
without going through PNG files. You can also combine SVG with
Postgis where the vector data is stored in Postgis and the SVG is
generated on the fly. You can see an example of this approach at
http://www.carto.net/williams/yosemite/ - for bigger SVG files it is
certainly faster if you store your geodata in a spatial database and
deliver customized extents, simplified versions and sub-selects
appropriate to the chosen mapscale.
Hope this helps,
Andreas
Jeremy Short wrote:
My goal is to render an SVG image map to PNG to display on our
website within a mapviewer of some sort with panning and zooming
capability. We have many maps. I want to use an Open Source
solution. Our web server is running Apache.
Additionally we want to add a "layer" of text labels which will not
get bigger when we zoom in. Too, since we have large pictures so
they don't degrade when one zooms in, we would like to explore the
ability to send only "tiles" of the map picture if it's required.
What I have found thus far:
1. Using OpenLayers as a client gives us the ability to load a PNG
file, pan, and zoom.
2. For the ability to add layers of text labels and transport tiles
of data I explored the possiblity to use Mapserver. It appears
Mapserver requires a map file like an SHP file as input and it will
output a PNG. I would like to feed it as input a PNG file but I
don't know if Mapserver is designed for this.
Looking further into this I see one can possibly use a tool like
gvSIG or AB Viewer to translate a PNG to a SHP file but I want to
automate the process without this extra step because people will be
modifying the SVG file periodically.
There seems like there must be a better way to accomplish what I
want which is to render PNG images in a client web browser with the
ability to navigate within the map and to render text labels and
transport tiles of information. Is there?
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