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Giovanni, I installed the QGIS + GRASS + PLUGIN as you suggested using the OSGeo4W installer. I can only use Grass Tools IF the layers are grass layers imported into a new map set. I do this but v.distance does not allow me to select the "From" vector file so the routine baulks. I am either (a) importing the shapefiles wrong, or (b) the development version of QGIS is not fully integrated with Grass Tools. I presumed that by going through QGIS I would be able manipulate the shapefiles directly. The problem with this option is to do simple vector queries requires a complete new GIS setup, two distinct programs (QGIS + GRASS) running, the need to convert shapefiles to grass format (the preference would be the ability to manipulate shapefiles natively) and the move project files to a central repository. What I will try is to run WinGrass again to cut out the middleman (in this case QGIS). Maybe it will work this time. tick, tick, tick... OK, I have installed WinGrass again. Since I created a mapset using QGIS the program opened once I pointed it to the default map location. Looking in more detail at v.distance I note it "Find(s) the nearest element in vector 'to' for elements in vector 'from'". Not what I needed. I need the distance of every feature from every other feature. That aside I find the routines are infinitely prescriptive - I presume you would be able to made the wizards choose defaults that could be changed by a user. As it is, it assumes you want to pick everything so it is a tedious task to figure out what needs to be done just to get one minor task completed. I spent about 40 minutes trying to select the various options to get this one routine to work - yes, I did read the manual. Eventually I gave up. Grass promises to provide immense power but in the absence of a easy to use GUI interface make it extremely difficult to utilize. I was hoping for the workflow... VECTOR1 + VECTOR2 == new tool, simple command line or GUI interface, one button ==> TABLE As its turning out with this option and the PostgreSQL option... (VECTOR1 => NEWVECTOR1) + (VECTOR2 => NEWVECTOR2) == new tool, complex, finicky, multiple processes ==> PROPRIETY TABLE ==> TABLE (if you are persistent). Giovanni, thanks for the tip of where to look. I'll keep playing with Grass but I don't think it will solve any of my short term needs as I don't have large amounts of time available to master this system (same problem with PostgreSQL). As it is I have already spent 5 hours trying to get the various options proposed to work - what is frustrating is that neither did. Cheers Simon
Simon Cropper Giovanni Manghi wrote: Hi |
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