Thanks Mathieu, Could you provide us with some numbers? How many geometries do you intersect? What is the total area/length covered by those geometries? With what raster size? How long it takes? Which kind of machine are you using? I would really like to use your numbers in my presentation.
Pierre > -----Original Message----- > From: Mathieu Basille [mailto:basi...@ase-research.org] > Sent: Wednesday, June 08, 2011 10:09 PM > To: PostGIS Users Discussion > Cc: Pierre Racine; Marie-Claude Labbé > Subject: Re: [postgis-users] How do you use PostGIS Raster? > > Dear Pierre, > > Here, we are using PostGIS to analyze large datasets combining rasters and > vectors. Basically, we are looking at movement and habitat selection in a > predator-prey system, using GPS-collar data over large areas. The major use of > PostGIS Raster is for the intersection of prey steps (line segments or buffers > around these segments) with different raster: > Landsat (landcover type), slope, road density, relative probability of > occurrence > of the predator, etc. Note that we first tried to use ArcGIS for this step, > without > success, due to many bugs and the need to correct them by hand (which was > largely too time-consuming). We also used PostGIS Raster to intersect predator > locations with the Landsat map to estimate Resource Selection Functions (RSF) > in order to build maps of relative probability of occurrence. In the end, > information of the intersections were used in R to characterize movements of > the preys on the landscape. > > Best, > Mathieu Basille. > > > Le 03/06/2011 08:28, Pierre Racine a écrit : > > Hi all, > > > > I'm preparing a presentation and I need some use cases for PostGIS Raster. I > would be grateful if people already using the raster side of PostGIS would > describe what they already do it. Bborie, Jorge, Regina, others? These uses > cases are vital for the project. > > > > On my side we are using PostGIS raster to do raster/vector analysis over > > large > datasets. Basically determining mean values for temperature (raster), > elevation > (raster) for fauna observations (point buffers). Converting everything to > vector > and using desktop solutions proved impracticable for datasets covering the > extent of Canada. > > > > For those who did not try the raster extension yet, don't be shy to express > > your > planned experiments or your expectations. > > > > Thanks all for your contribution to the project, > > > > Pierre > > _______________________________________________ > > postgis-users mailing list > > postgis-users@postgis.refractions.net > > http://postgis.refractions.net/mailman/listinfo/postgis-users > > -- > > ~$ whoami > Mathieu Basille, Post-Doc > > ~$ locate > Laboratoire d'Écologie Comportementale et de Conservation de la Faune > + Centre d'Étude de la Forêt > Département de Biologie > Université Laval, Québec > > ~$ info > http://ase-research.org/basille > > ~$ fortune > ``If you can't win by reason, go for volume.'' > Calvin, by Bill Watterson. _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
