Ned, On Tue, Jan 20, 2009 at 6:25 AM, Ned Horning <[email protected]> wrote: > Markus, > > Thanks for the feedback. The advice is very helpful. I've been slowly getting > used to GRASS but still have a way to go. If I can stick with it I hope to > learn > enough to create a week-long "GRASS for conservation" workshop that we can > offer > at our research station in southeastern Arizona and in our projects in SE > Asia.
just keep asking and reading :) > Here are some clarifying remarks and a few more questions if anyone can help. > >> It will work. Everything takes time but I don't expect problems. GRASS 6.2 > >> has been used for >10GB images, since then more testing and fixing >> happened. Best is to use the latest 6.4.0RC2 version. > I'll see if I can get this version set up so it doesn't conflict with the > GRASS > version bundled with QGIS. My linux (Ubuntu) skill are also still quite poor > but I'm learning (again). It doesn't conflict. You can have separate GRASS installations as you like. >>> 4) Georeference shrub / non-shrub map to reference Landsat images [might >>> do this with ENVI or ERDAS unless GRASS is a good choice] >>> >> >> Also unclear to me: above you say that you generate the shrub / non-shrub >> map in GRASS, then it is already geocoded. Or not? > > Sorry - I wasn't very clear. The images I'm working with are geocoded but the > image-to-image registration is poor. I plan to project all of the images into > the same projection (some are in UTM and some use different datums) and then > do an image-to-image registration. I wasn't sure if GRASS would be an > efficient > tool to do the image-to-image registration. I should just try it. There is a graphical geocoding tool available in the user interface. See http://grass.osgeo.org/screenshots/imagery.php >>> 5) Create percent shrub cover map using regression tree algorithm, Landsat >>> imagery, and shrub location data from the high resolution shrub / >>> non-shrub map. >>> I will probably do this using proprietary software unless I can do it >>> easily in >>> GRASS since a method has been established for another project. >>> >> >> Of course GRASS-R-extention comes to mind for all kinds of statistics. > > I'm considering using GRASS for this but would like to know if anyone has used > GRASS with R as the regression tree engine. > > I have a vague recollection of someone > doing this several years ago but didn't find anything after a quick search. > I suppose it would require getting training data from GRASS to R to generate > the regression tree and then port the tree results back to GRASS to apply the > rules to the dataset. It would be great if an interface already existed to do > this but if not I can probably figure it out. I'm just not sure how long it > will take me. We did a CART some years ago using GRASS and R: http://www.citeulike.org/user/neteler/article/172938 Best Markus _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
