[postgis-users] Elevation profiles from rasters

[Pierre Racine]

Try 100x100...

> -----Original Message-----
> From: postgis-users-bounces at lists.osgeo.org [mailto:postgis-users-
> bounces at lists.osgeo.org] On Behalf Of Rasmus Aveskogh
> Sent: Wednesday, August 27, 2014 11:08 AM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] Elevation profiles from rasters
> 
> Thanks,
> 
> I'm using the technique described at http://blog.mathieu-
> leplatre.info/drape-lines-on-a-dem-with-postgis.html
> 
> What would be small tiles in this context? 256x256? The raster I was testing
> against was ~1200x1200.
> 
> -ra
> 
> On 27 Aug 2014, at 16:19, Pierre Racine <Pierre.Racine at sbf.ulaval.ca>
> wrote:
> 
> 
> 	Elevation profile should be quite fast depending on how you tile
> your raster coverage. Smaller tiles make computation faster. Index them
> and make sure your query is actually using the index.
> 
> 	Pierre
> 
> 
> 
> 		-----Original Message-----
> 		From: postgis-users-bounces at lists.osgeo.org
> [mailto:postgis-users-
> 		bounces at lists.osgeo.org] On Behalf Of Rasmus Aveskogh
> 		Sent: Friday, August 22, 2014 4:10 PM
> 		To: postgis-users at lists.osgeo.org
> 		Subject: [postgis-users] Elevation profiles from rasters
> 
> 		Hi!
> 
> 		How hard/feasible would it be to implement elevation
> profile/drape line
> 		functionality in PostGIS? Since PostGIS already depends on
> GDAL I assume
> 		making use of the GDAL API would make this quite easy,
> such as in the Zoo-
> 		Project service:
> 
> 		http://www.zoo-project.org/trac/browser/trunk/zoo-
> project/zoo-
> 		services/gdal/profile/service.c
> 
> 		Providing functionality that could eventually be used for
> applications like:
> 		http://www.zoo-
> project.org/site/ZooWebSite/Demo/GdalProfile (using the
> 		code above)
> 
> 		I'm currently using an ad-hoc PostGIS-function to pull out
> elevation profiles
> 		from my rasters, but it's quite slow and CPU intensive and
> as such does not
> 		make a good fit as a backend service for a web application
> like the above.
> 
> 		-ra
> 
> 
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