GRASS GIS (Geographic Resources Analysis Support System) is a free, open source geographical information system (GIS) capable of handling raster, topological vector, image processing, and graphic data.
0
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1answer
10 views
Raster image outside Grass screen, How to get it inside from start?
HI ALL: I'm new in Grass and need some help!
I have created a LOCATION based on the coordinate system in which I want my data to be projected. So far I'm being able to Import & display the raster ...
0
votes
1answer
37 views
Problem opening GRASS GUI: libgeos-3.3.6.so: cannot open shared object file:
I have been using GRASS to process some Landsat imagery but very recently, and as far as I am aware - after having done nothing different or changing the settings, I am trying to use GRASS and on ...
4
votes
1answer
74 views
R gridding and contouring options
I want to make an interactive web mapping application, which will grid and contour user data. My plan is to implement R scripts with Shiny, but the only R package I can find to do this is gstat. And ...
9
votes
4answers
1k views
How to connect lines in a network?
I have a shapefile of lines and another of polygons. When two or more lines intersect a polygon they should be connected (snapped), but sometimes during manual digitization this doesn't occur. I need ...
14
votes
3answers
313 views
How to do kernel density estimation with a physical barrier/ boundary in QGIS?
Does anyone know of a programme that will allow kernelling that takes a boundary into account in its calculation rather than simply masking areas that are impossible?
So far I have found:
GME add on ...
-1
votes
1answer
38 views
Is it possible to import/run AML script into GRASS?
I have an AML script that has instructions to import tmp files of (grid, network, basin...)
is there any way to run the script in GRASS? I tried to converted to Python but I couldn't do it for the ...
0
votes
0answers
36 views
After pansharpening LANDSAT 8 in GRASS, poor colour visualisation in QGIS afterwards
Having used QGIS for quiet some time for mapping, I was 'forced' to dig into GRASS as pansharpening is not directly executable in QGIS. After understanding more or less the structure, I did some ...
2
votes
0answers
285 views
Simulate flood to assess Asset inundation footprints
I am trying to evaluate a number of flood gauges to assess at what levels of river height different flood risks would need to be issued. The gauges are currently set to warn of flood a couple of ...
2
votes
1answer
70 views
Issue while running grass from subprocess
I have a map based web application using geodjango. I needed to display the crime hotspots within a selected polygon area. I found that v.kernel is very good for generating heatmaps/hotspots. So in my ...
0
votes
1answer
118 views
How do you use 'reclass' in GRASS?
It could be user error, but for some reason, the reclass tool is just hanging and hanging...
QGIS 1.8
Compiled against GDAL/OGR 1.9.2
Ubuntu 12.04.1
Running the tool from the Sextante toolbox
Input ...
1
vote
1answer
33 views
Use of Grass and R w.r.t. Land Use Prediction
In my data mining term project I need to conduct a work on geospatial data related to a big city to show possible urbanization fields in next years. I've used GRASS lately on other projects so I'm a ...
1
vote
1answer
59 views
Showing map in Grass Layer Manager/Map Display via Python
I've created some raster(tif) maps using Grass libraries in Python. I want to opem them automatically in Grass GIS Map Display or Layer Manager after creation. I don't want to use GUI for this. What ...
4
votes
1answer
79 views
Help installing add-on in GRASS, I get an error message
My Grass gives me this error message, Grass_info_error(4816,1):'make' required. Please install 'make' first. This happens when I attempt to fetch an add-on (r.viewshed). What am I doing wrong? and ...
0
votes
0answers
9 views
How do I determine the area of a raster map in GRASS in real world units? [duplicate]
I know that in the metadata it gives you the number of cells, but how do you find out what area (in, for example, metres squared) a cell represents?
2
votes
1answer
71 views
GRASS : r.resamp.rst error : “Not enough disk space--cannot write files”
Today, I am confronted to a difficulty I cannot manage.
When I try to use the tool "r.resamp.rst", it gives me as answer:
*r.resamp.rst input=map@PERMANENT ew_res=11 ns_res=11 pcurv=curv
...
0
votes
1answer
92 views
Sextante grass folder incorrect?
What is the correct grass folder in Sextante? I alway get this message:
The specified GRASS folder does not contain a valid set of GRASS
modules. Please, go to the SEXTANTE settings dialog, and ...
0
votes
0answers
15 views
GRASS 6.4.3RC3, Python script and windows7
I'm trying to solve my problem for a long time. I hope someone can help me. I'm not expert but I really want to istall 2 add-on on grass 6.4.3RC3 on my win7. The add-ons are r.basin and r.ipso. I ...
0
votes
0answers
20 views
Python errore addons (win)
I have this type of error when I try to use r.ipso:
C:\Program Files (x86)\GRASS GIS
6.4.3RC3\extrabin\python.exe: can't open file 'r.ipso.py':
[Errno 2] No such file or directory
while with r.basin ...
1
vote
2answers
62 views
Grass 6 extension installation in Grass 7 error
I am trying to install the extension r.roughness from the Grass 6 repository, but in Grass 7.
When trying g.extensions, the error "make: * No rule to make target ...
0
votes
1answer
35 views
r.basin.py GRASS addon
I have added this add on with g.extension on my grass 6.4.3RC3. But it doesnt work... this is the error I can see:
Traceback (most recent call last): File "C:\Program Files (x86)\GRASS GIS ...
1
vote
2answers
95 views
r.regression.multi - ERROR: Not enough valid cells available
I am running a few analyses with r.regression.multi in Grass 7. For a few rasters that I try to correlate, the following error comes up, however: "ERROR: Not enough valid cells available".
I cannot ...
0
votes
1answer
37 views
Add-ons on GRASS (win7)
Can someone help me fro istalling add on on GRASS 6.4.3RC3 (windows7)?? I tryed several mode but I'm not able. I found several topic here and into the web but it doesn't works.
I use g.extension, I ...
13
votes
3answers
1k views
Visual Impact Assessment in QGIS or GRASS
Is it possible using QGIS or GRASS to perform a Zone of Visual Impact assessment? E.g. where can a 100m high structure be seen at a viewing height of 1.8m within 30km, taking into account elevation ...
0
votes
0answers
28 views
SEXTANTE v.to.rast.attribute issue in script
I'm trying to convert a vector layer to a raster by using the GRASS function v.to.rast.attribute in Python.
My code doesn't throw any error but the raster image is only a square of 1px. But when I'm ...
0
votes
0answers
25 views
How can I calculate raster cell area for upslope contributing area
I am new to spatial analysis, and urgently trying to follow this tutorial to generate a topographic wetness index for my area of interest:
...
2
votes
1answer
124 views
Grass v.clean.snap with Polygons
I am doing some topology testing using Grass in QGIS. I am hoping to snap nodes to eliminate gaps between polygons. When I use the v.clean.snap function in Grass it does not work on polygons. When I ...
0
votes
0answers
15 views
How to access layer attributes using grass network tools (v.net.iso)?
I had a quick look for a similar question, sorry if this is a duplicate.
I am using GRASS 6.4.3 on windows - osgeo4w version
I ran v.net.iso to split my road network by cost however when I try to ...
0
votes
1answer
59 views
How to setup and use GRASS?
Previously I've asked an question and Micha gave me a helpful advice:How to find the watershed area for each point in the river network using DEM？
After getting the useful DEM file, I began to setup ...
0
votes
1answer
29 views
3D Interpolation using point cloud in GRASS GIS
I've imported a set of 3D points (z,y,z) into GRASS GIS. I'm having trouble: a) visualising my dataset in 3D using nviz or the standard data viewer (I can only get a 2D plan view of my data) and, b) ...
3
votes
2answers
103 views
Autocorrelated DEM with QGIS or Grass
I was wondering if there is a way to make an Autocorrelated DEM within QGIS or Grass. I am looking to do this with stereo aerial photography. I am able to do this with a number of COTS tools, but I ...
4
votes
0answers
65 views
Is r.cost equivalent to diffusion interpolation with barriers?
I want to perform interpolation using cost distances rather than euclidean distances similar to Greenberg et al. (2011). In that paper they use r.cost in GRASS to compute cost distances for each ...
0
votes
2answers
77 views
How do I reproject one raster to match another's in GRASS
I have two raster layers, A and B, which have information about the same location but have different projections and datums.
How can I reproject layer A to match the projection and datum of layer B?
...
1
vote
1answer
86 views
How to find the watershed area for each point in the river network using DEM？
As title, I want to find the watershed area, but using QGIS.
I have following files to work with：
stream network shapefile(polyline)
point shapefile clipped from the polyline shapefile
a whole ...
0
votes
1answer
31 views
how to loop grass command in python and put variable in output file
anyone,
first day Grass programming with python scripting;
first prob;
simple I want to reclass the same raster several times;
and save the file with the value loop variable at the end ...
can not ...
0
votes
1answer
22 views
How to estimate distance from points to line feature with v.distance?
I'm trying to use the v.distance module in GRASS 6.4.3 to estimate the distance from a series of point features (animal tracking locations) to the nearest point along a line feature (a coastline). I ...
0
votes
1answer
48 views
Why can't I load more than 12 elevation files into NVIZ?
I have a large set of rasters in a GRASS mapset, which I would like to use as frames in an animation, visualizing the raster data as elevation. NVIZ is an obvious tool for this, but I'm having trouble ...
6
votes
1answer
248 views
How to perform unsupervised classification of LANDSAT time series using Grass?
I'm using GRASS to perform an unsupervised classification on a time series of LANDSAT images (monthly temporal res, over 30 years), in order to compare land cover change in a particular area.
I'm ...
0
votes
2answers
96 views
Error from ps.map in GRASS. How to fix?
I'm trying to learn how to use ps.map in GRASS. I thought that running it in interactive mode from the command line would be a good place to start, but I'm getting the following error:
> ps.map ...
2
votes
0answers
44 views
How to create a topologically correct dataset in PostGIS (with GRASS)?
I have shapefiles which I have loaded in postgis and now i am trying to use geometric function in postgis like ST_intersect and they fail because the data is not topological correct.
I have tried to ...
2
votes
2answers
346 views
r.mapcalculator and python again
I've been trying to write a script creating binary maps:
a=raw_input ("enter a threshold")
b=float(a)
grass.run_command('r.mapcalculator', formula="**'base_map'>=b**", outfile='map'+str(a), ...
2
votes
2answers
229 views
run r.stats as a quiet module in GRASS-Python script
Has anyone else used r.stats as a quiet module in a GRASS-python script?
As part of my program I'm using:
grass.run_command("r.stats", flags='l', input=<file>, output=<*.csv file>, ...
0
votes
0answers
27 views
GRASS - Creating an Attribute Based on Driving Distance
Is it possible to calculate the driving distance for each node of one layer (fire stations) to each node of another (address points)? After doing so, I need to sort all of the distances from shortest ...
0
votes
2answers
46 views
How to align directions of connected lines?
I have a vector line made of different pieces of lines with different directions. I merged the lines to one. But this merged line still have different direction in its "invisible" parts. I want to ...
0
votes
0answers
64 views
Grass won't import shapefiles
I have a problem involving the import vector data command, specifically importing shape files. I installed QGIS on a pc at work and there I could import shape files into GRASS GIS 6.4.3RC2 (which is ...
1
vote
1answer
48 views
Grass7 - r.regression.multi and new raster
I am on the learning curve with Grass7. I managed to make r.regression.multi work, but there is one thing that would be of high interest for me: it is possible to create a new raster showing the ...
0
votes
0answers
52 views
Why don't libgrass.so.1.8.0 and libqgissqlantconnection.so.1.8.0 load?
I have compiled Qgis 1.8 at Ubuntu 12.10, but some phyton plugins does'nt work, like sextante.
Trying to solve this problem, some files don't have been load. They are: libgrass.so.1.8.0 and ...
2
votes
1answer
313 views
QGIS is not able to find GRASS. Choose the path of installation folder of GRASS
I've downloaded and then correctly installed QGIS 1.7.4 for windows (Win 7 64bit is my version) in C:\Programs\Quantum GIS.
But everytime I start QGIS this popup appear: "QGIS is not able to find the ...
1
vote
1answer
122 views
QGIS contour lines shapefile to DEM help
I want to create a DEM from depth contours (shapefile) in QGIS. I've been trying to work out how to do this based on this previous question, notably from this link from that page, however I'm stuck, ...
1
vote
1answer
427 views
Is there any pseudocode for MFD (multiple flow direction) algorithm available?
Still stuck with the simulation system, is there any good pseudocode for the multiple flow direction (MFD) algorithm? I read a pseudocode example and implemented it, however the simulation was linear: ...
1
vote
0answers
30 views
GRASS v.overlay.or Error when trying to split a polygon with a line
I am using the Grass plugin in QGIS for Windows (1.8.0). I am trying to split a polygon with a line feature. I am using the v.overlay.or function within the QGIS Grass plugin. I have the line layer ...
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