[Qgis-user] Add SVG As Vector Layer

[Neumann, Andreas]

Hi David, 

I am also a cave explorer and SVG fan - so I understand your desire to
use SVG as a format to transport data from a specialized cave software
(Therion?) to QGIS. 

Unfortunately, support for reading SVG as a map layer source is
non-existent in QGIS. SVG is not a GIS format and thus there were no
efforts made to read those. It is also not well suited for georeferenced
data. 

As you discovered, OGR does support a very limited subsection of SVG
(only point, line, polygon - without curves/beziers and requires a
certain header). It has also very limited styling support. 

This doesn't mean it wouldn't be technically possible. Since SVG is a
lot about styling, if I had to implement SVG as a QGIS layer data
source, I would probably try to use QtSVG to render the files (because
it better works with styling than OGR). You would then still have to
georeference the imported rendered SVG image. It is technically
possible, but it would probably mean a couple of days of work for an
experienced QGIS developer. 

Are you a qt/QGIS developer or do you know one? 

------------- 

Have you also thought about drawing the map entirely in QGIS? It would
have some advantages and disadvantages. I did some tests and the results
where quite pleasing. It wouldn't have the ability to warp the data if
the cave survey data changed (like Therion does), but there is no reason
why the same warping functionality wouldn't be possible in QGIS as well.
I guess for the long run, QGIS may even be the better platform, if the
Therion/Survex developers would invest into that platform. It would open
a lot of possibilites for further use and and analysis of the data. 

Greetings,
Andreas 

On 2016-02-16 05:57, David A. Riggs wrote: 

> I'm working with cave maps and the sketch drawings from which they are made. We digitally draft the sketches in-cave, and the resultant file is a layered SVG file (using some XML tricks so that both Adobe Illustrator and Inkscape recognize "layers", something not actually built into the SVG specification itself). We then produce a vector representation of the survey in SVG, draft the working map in SVG using the survey and sketches, and then subsequently "morph" the vector nodes in the SVG working map as later surveys shift portions that change due to error correction of the survey. 
> 
> I'd like to be able to import these georeferenced SVG files into QGIS as either a single vector layer, or - in an ideal world - as with their non-standard SVG layers imported as independent vector layers in QGIS. As far as I can tell, there is no standard (or non-standard) for georeferencing an SVG file such that QGIS could recognize it! 
> 
> The OGR docs mention a specific product's version of SVG, in a fixed CRS, which they support for reading. It looks like this product is "Cloudmade Vector Stream Server", which appears to be a dead web service? 
> 
> http://www.gdal.org/drv_svg.html 
> 
> Does anyone have more information on ways to directly georeference an SVG file for import as a QGIS vector layer? Perhaps using a VRT?  
> 
> Note that converting to DXF or some _other_ format is not what I'm asking about! 
> 
> Thanks! 
> 
> - DR 
> -- 
> 
> David A. Riggs <david.a.riggs at gmail.com>
> 
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