[postgis-users] 3D maps

[Andreas Neumann]

alternatively you could output your 2d data as KML and visualize it in
Google Earth. I know that the DTM is not too good in GE, but it is a quick
and cheap solution.

Andreas

> Hi Paul,
>
>
>
> I'm not aware of any built in procedures available in PostGIS. Something
> could be worked out possibly but you would need to pull out the triangles
> as
> line segments and intersect individual lines before interpolating a z
> value.
> This is a lot of work and I doubt that it could be done efficiently. You
> would have to write the splitting and interpolation yourself.
>
>
>
> Perhaps you should look at one of the open source terrain modeling tools.
> I'm thinking of grass.
>
> http://grass.itc.it/ or  http://www.jgrass.org/cgi-bin/moin.cgi
>
>
>
> Here is a potential work flow:
>
> 1. Convert your TIN to a surface
>
> http://grass.itc.it/grass63/manuals/html63_user/v.surf.idw.html
>
> I believe Grass is memory limited so if the TIN is very large you may have
> to tile and iterate through a tile set.
>
> You could possibly work out something using the pg driver
> http://grass.itc.it/grass63/manuals/html63_user/grass-pg.html
>
>
>
> 2. Use the resulting surface to process 2D polyline into 3D polyline
>
> http://grass.itc.it/grass63/manuals/html63_user/v.drape.html
>
> You may want to densify the 2D first with
> http://grass.itc.it/grass63/manuals/html63_user/v.split.html
>
>
>
>
>
> Hope this is helpful
>
>
>
> Randy
>
> http://cadmaps.com/gisblog/ <http://www.cadmaps.com/gisblog.htm>
>
>   _____
>
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Malm
> Paul
> Sent: Monday, November 19, 2007 7:53 AM
> To: PostGIS Users Discussion
> Subject: [postgis-users] 3D maps
>
>
>
> Hi!
> I have a geometry set of triangles (e.g land area), including elevations.
> To
> be able to view e.g roads ontop those triangles I must insert points in
> the
> road polylines with the correct elevation in each intersection (roadline -
> triangle border). Att the same time I would like to insert the correct
> elevation of the original points of the road-polyline. is there a command
> in
> PostGIS that could do this for me?
>
> Kind regards,
>
> Paul
>
> _______________________________________________
> postgis-users mailing list
> postgis-users at postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-users
>


-- 
Andreas Neumann
Böschacherstrasse 6, CH-8624 Grüt/Gossau, Switzerland
Email: a.neumann at carto.net, Web:
* http://www.carto.net/ (Carto and SVG resources)
* http://www.carto.net/neumann/ (personal page)
* http://www.svgopen.org/ (SVG Open Conference)
* http://www.geofoto.ch/ (Georeferenced Photos of Switzerland)