[postgis-users] 3D geometries

[Stephen V. Mather]

It seems like this could be addressed by overloading the function so that
whether the function builds tunnels and bridges is an option.

Steve


Stephen Mather
Geographic Information Systems (GIS) Manager
(216) 635-3243
svm at clevelandmetroparks.com
clevelandmetroparks.com




-----Original Message-----
From: Havard Tveite [mailto:havard.tveite at umb.no] 
Sent: Thursday, March 15, 2012 4:14 AM
To: svm at clevelandmetroparks.com; PostGIS Users Discussion
Subject: Re: [postgis-users] 3D geometries

Hi,

For "ST_SetMFromRaster(geom, rast)", I think it would be
better to only add the Z/M value to the points of the input
geometry.  Those that want to do something like ST_Densify
should do that as a separate preprocessing step.
This would give the user more control of the process (the
user may want tunnels and bridges).

Håvard

On 3/13/2012 7:47 PM, Stephen V. Mather wrote:
> Hi Pierre,
>
> I could try my hand at this as a PL/pgSQL function.  Can't help with the
> C++... :)
>
> I'm thinking ST_Densify ala Paul deriving the densification from the cell
> size of the input raster, then use st_dumppoints and st_intersects, and
then
> reconstruct to 3D line (or am I thinking too low level to be efficient).
>
> Best,
> Steve
>
>
> Stephen Mather
> Geographic Information Systems (GIS) Manager
> (216) 635-3243
> svm at clevelandmetroparks.com
> clevelandmetroparks.com
>
>
>
>
>
> -----Original Message-----
> From: Pierre Racine [mailto:Pierre.Racine at sbf.ulaval.ca]
> Sent: Tuesday, March 13, 2012 2:22 PM
> To: svm at clevelandmetroparks.com; PostGIS Users Discussion
> Subject: RE: [postgis-users] 3D geometries
>
> Hi Stephen,
>
> It would certainly be very nice to have a generic function doing it:
>
> SELECT  ST_SetMFromRaster(geom, rast)  geom
> FROM mylines, myrast
> WHERE ST_Intersects(geom, rast)
>
> Pierre
>
>> -----Original Message-----
>> From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-
>> bounces at postgis.refractions.net] On Behalf Of Stephen V. Mather
>> Sent: Tuesday, March 13, 2012 1:43 PM
>> To: postgis-users at postgis.refractions.net
>> Subject: [postgis-users] 3D geometries
>>
>> Hi All,
>>
>>                  Any special considerations for turning a 2D multi-line
> geometry into a
>> 3D geometry using a DEM as a RASTER within PostGIS?  Has anyone played in
>> this arena?
>>
>>
>>
>> Thanks,
>> Steve
>>
>>
>>
>> http://www.clemetparks.com/images/esig/cmp-ms-90x122.pngStephen Mather
>> Geographic Information Systems (GIS) Manager
>> (216) 635-3243
>>
>> svm at clevelandmetroparks.com
>> clevelandmetroparks.com<http://www.clemetparks.com/>