4,302 reputation
36
bio website surfaces.co.il
location Israel
age
visits member for 2 years, 4 months
seen yesterday

I work at the Arava Drainage Authority and Regional Council in southern Israel, doing hydrological analysis and general mapping. Involved with open source software since 1996, and FOSS GIS since 2006. I've also organized a few short GIS training seminars based on open source software.


Jul
23
answered GRASS: v.drape, v.split and v.to.db on spearfish sample data
Jul
19
answered LiDAR data density, returns per square meter
Jul
16
answered Is my code for changing the resolution correct?
Jul
8
comment Help choosing an appropriate GIS solution for the following question
Everything in your question are straight-forward, basic GIS operations. You certainly can do all of the above in QGIS, for example. May I suggest you begin by scanning the QGIS documentation
Jul
8
comment Shortest distance from polygon centroids to a line in QGIS
The GRASS plugin in QGIS (and the whole Processing menu for that matter) are meant to be a bit more "user friendly" than the full GRASS/SAGA/OTB packages. As such some less used options are left out. So, you might say that the QGIS implementation is "incomplete". I wouldn't put it that way, just more accessible.
Jul
6
answered Adjacency matrix in GRASS
Jul
4
comment Shortest distance from polygon centroids to a line in QGIS
First note that v.distance (in GRASS 6.4, which is what QGIS uses) finds the distance only from points to lines. So you need to specify the type=centroid option if your (from) layer is polygons. Next you do need to create the target attribute column in your "to" layer (the lines) in advance.
Jul
4
comment Count points in a polygon that changes form (“on the fly calculation”)
You need to import the layers into a Spatialite database, and do the trigger there. I recommend spatialite-gui for this.
Jul
3
answered Count points in a polygon that changes form (“on the fly calculation”)
Jul
1
comment How can data of columns of the attribute table be refreshed automatically?
No, It won't update automatically. To have that happen you need your data saved in a database, with a trigger to recalculate attributes such as area each time the table is updated.
Jun
28
comment Help me to understand how i.fusion.brovey works in Grass 6.4.3
I think you've done everything right so far. All you need now is r.composite to get a three band colored image. And the result ("false color" or "true color") Depends on which of the original bands you choose.
Jun
27
comment What is format of Natural Earth SQLite database GEOMETRY column?
If I'm not mistaken, Spatialite uses a special format for the Geometry databse "blob". Not exactly WKB. See here. If you need a standards compliant WKT or WKB representation, then you should use ST_AsText() or ST_AsBinary() .
Jun
24
comment GRASS workflow for volume calculation
Not sure I understand where r.volume and clumps are relevant to your problem. But if you do (DEM1-DEM2)*cell_resolution you will get the "cut/fill" volume between two elevation raster.
Jun
23
comment GRASS workflow for volume calculation
Can you try what I mentioned? Make sure the raster has only values 1 or NULL, and set the region to this raster.
Jun
20
comment GRASS workflow for volume calculation
What do you mean "goes undone"?? I think you should add two more steps to E: r.null <your mask> setnull=0 to make sure that the areas outside of the polygon are NULL and not 0. Also be sure to do g.region -p rast=<your mask>
Jun
13
comment GRASS raster map types: UInt16 and Float64
The error only regards the color table. Should be harmless.
Jun
8
answered QGIS GRASS plugin: r.composite quality loss
Jun
7
comment Convert a mask image to polygon shape file using GRASS
I guess I wasn't clear. v.in.ascii does not create any table at all, (unless you have additional columns other than the coordinates). After importing the pts.txt, try running: v.db.addtable pts_vecorMap columns="x double precision, y double precision, z double precision, status integer" then do the v.to.db command as above.
Jun
6
revised Calculating slope in percentage
added 13 characters in body
Jun
6
comment Run this module in GRASS 6.4.3 command line in Windows 7 or QGIS Grass Module
A for loop in Windows cmd is done as for /F %FILE% in ("*.hdf") do .... And the equivalent to basename is %~ni. Maybe that will get you going.