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.

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487 views

QGIS GISBASE specify location

I am just a beginner at this QGIS and GRASS and I am using this QGIS 2.0.1 Dufour which throws a error at the startup that "QGIS couldn't find your GRASS installation. Would you like to ...
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2answers
124 views

How to create a time series with a NetCDF raster from Ensembles E-OBS using GDAL, R, GRASS GIS or SAGA GIS

I downloaded a NetCDF file that contains daily precipitation values from 1-1-1950 to 30-6-2013. The raster has 23191 bands. http://eca.knmi.nl/download/ensembles/download.php My goal is to analyze ...
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1answer
41 views

How to mask the images in GRASS

I have MODIS NDVI images, which needs to be masked with VI_Quality. I am using GRASS software and executing GRASS commands using shell scripts. I need to perform raster calculation (multiplication) ...
2
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2answers
864 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 ...
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1answer
21 views

GRASS module g.mremove returns irrational outputs

I want to use g.mremove to remove multiple files in my mapset, import os import sys sys.path.append(os.path.join(os.environ['GISBASE'], 'etc', 'python')) import grass.script as g import ...
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2answers
180 views

Why my python script of r.watershed has no output?

I type those code in pyscripter, import os import sys #set up GRASS environment variables sys.path.append(os.path.join(os.environ['GISBASE'], 'etc', 'python')) import grass.script as g import ...
0
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1answer
66 views

GRASS module g.copy returns irrational outputs

I took this as reference, Moving raster to different mapset GRASS GIS, and I use pyscripter to use GRASS module g.copy from outside, import os import sys #set up GRASS environment variables ...
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0answers
78 views

GRASS module g.mapset can't create new mapsets from outside

I use pyscripter to control GRASS from outside. I want to create a new mapset named water. Here's my script to generate new mapset, import os import sys #set up GRASS environment variables ...
0
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1answer
92 views

v.edit break: how to loop through XY coordinates on using GRASS on Windows 7

Trying to follow the suggestions on this thread: splitting a lines layer using points However, how to do so in a windows environment using the GRASS command console is beyond me, so I'm attempting ...
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2answers
115 views

Grass GIS 6.4.3, How to create a .PTS file

I'm trying to export a raster map in order to use it in the Flo-2d program. This program needs a .pts DTM file, do you know how I can create it? Alternatively, I can use a XYZ file looking like this ...
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1answer
20 views

vector file is used by two mapsets at a time in grass gis

i want to study about vector processing.if a vector file is used by two mapsets at a time, which one will be saved first and why.if a team want to work on the same set of shape files, what is the ...
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2answers
86 views

How to number points along a line consecutively

I have a line and along this line I have different points which are max. 20m away from that line. Now I would like to number the points along the line, like shown in the grafic. Any suggestions how to ...
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0answers
11 views

Printing a label from a point layer attribute on a raster layer (GRASS)

I am interpolating with boundaries using v.surf.idc in GRASS. It works wonderfully and I fully recommend it. I am creating an animation and I use v.surf.idc to generate sequential interpolated raster ...
0
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1answer
45 views

Better ways to check if GRASS r.water.outlet works out fine output

I use my python script to call GRASS module r.water.outlet from outside, and here's my script(I perform this script in pyscripter): import os import sys #set up GRASS environment variables ...
0
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1answer
148 views

The same error message shows up while running GRASS command

I'm using GRASS 6.4.3(installed with OSGeo4W) under Windows 8.1 x64. When I type commands in the command console below, I often face these problems: type command which has "space", like:g.list ...
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0answers
77 views

No data appears when using gdal_calc.py but source had data values

I'm in the process of calculating topographic exposure using a mix of GDAL, grass, R and python in Windows. I need to process a very large tiff file using the following calculation: ...
2
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2answers
82 views

How to do the loop when using GRASS module r.water.outlet?

I have seen this post:Watershed Analysis with GRASS, and I have a .txt file which contains coordinates of many points, and I want to use r.water.outlet to get basin area of each point. I type the ...
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0answers
11 views

Grass - How to add average elevation of line features to a new colum

I have a shape file with 3-D (contour) lines. The vertices of any single line may have tiny differences in the z-value (elevation). Ho can I create a new column "ele" and fill it with the average ...
3
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3answers
372 views

Convert 800 .hdf4 files to Tiff using GRASS/QGIS/SAGA/GDAL/R

I've have MODIS ndvi data (MODIS_Grid_16 days NDVI) from the iberian peninsula, from February of 2000 to August of 2012 (really big data). How do I batch convert about 800 .hdf MODIS files to .tif ? ...
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3answers
275 views

Problem with python script to control GRASS GIS from outside - How to import grass.script under Win 8.1?

I am working with GRASS 6.4.3 and python 2.7.6 under WIN 8.1. I am a novice with computer science and coding, and I have seen many posts including those:Is it possible to use GRASS GIS in Python ...
0
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1answer
51 views

Difference between python IDLE and eclipse on accessing GRASS

I have seen these posts:GRASS and Python, Using Eclipse to develop GRASS Python programs. I used to use python IDLE to control GRASS, but I can't make python and GRASS connected, as I described in ...
2
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1answer
64 views

Matching two point clouds without loss (nearest neighbor, but more complicated)

I have two point clouds, one with demographic and one with electoral data. Points in both clouds represent the same empirical entity (say, a village, or an urban neighbourhood), but are not in the ...
1
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1answer
635 views

How to process MODIS ndvi data using QGIS/GRASS/R?

I have MODIS ndvi data (MODIS_Grid_16 days NDVI) from the iberian peninsula (3 tiles), from February of 2000 to August of 2012 (really big data). I want to know how to deal with this kind of files. My ...
0
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1answer
55 views

RuntimeError from r.viewshed in graphic modeler

after using r.los in QGIS want to switch to r.viewshed in GRASS GIS 7. i need to do a lot of viewshed analysis form given points of a vectorlayer. if i try to add r.viewshed to the graphic modeler i ...
2
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2answers
173 views

How to increase resolution of 3D image in GRASS NVIZ

I am trying to make 3D visualization of terrain data and orthophoto using GRASS NVIZ via QGIS. I have been able to import both the DTM and the orthophoto in NVIZ window and successfully draped the ...
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0answers
97 views

Defining the boundary of a catchment area

I digitized contour lines from topographic maps and created a DEM. With the DEM, I estimated the boundary of a catchment area. Estimated positional accuracy of topographic maps is RMSE = 65 m, with a ...
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0answers
34 views

GRASS GIS - v.select- ERROR: bad allocation -

I'm quite new to Grass GIS. I have two vector maps, one of a grid (each grid cell is a polygon) and one of a much larger polygon. I've been trying to select the grid cells that lie completely within ...
5
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2answers
187 views

Creating contours for specific elevations

Input data: 1. an SRTM raster. 2. Point file of peaks. -Attributes contain ID, x, y, z and the elevation at which the peak is completely isolated from a neighboring peak. The output I want is a ...
1
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1answer
76 views

Can one batch-automate the creation of QGIS heatmaps?

I have 4k point shapefiles, from which I would like to generate heatmap TIFFs using the QGIS heatmap plugin (or a functional equivalent featuring triweigth, radius and cell size selection). Is there ...
0
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1answer
64 views

QGIS-Processing GRASS-tools don't work

When I try to use the processing grass tools like r.series I always get the following messege. I deinstalled QGis and reinstalled the program totally fresh without success.
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92 views

Grass 7 voronoi vertices error

I tried the voronoi diagram for area function and got the message "ERROR: Found 0 vertices" - any suggestion ?
2
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0answers
153 views

Snap points to line and calculate chainage using Open source GIS

I have a line layer (representing a pipeline) and a points layer (representing valves) and I would like to calculate the chainage of the valves along the pipeline. I assume that I would first need ...
0
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2answers
76 views

Interpolation using GRASS plugin in QGIS

I have been using the IDW interpolation tool through GRASS plugin in QGIS and the interpolation output I am getting is for the entire mapset region. My question is: Is there a possibiltity that we ...
0
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0answers
41 views

r.shaded.relief plugin on a DEM layer

I loaded a raster digital elevation map from the DEM explorer website. I defined the projection and created a mapset. I then loaded the raster file into GRASS with the r.in.gdal plugin to create a DEM ...
2
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2answers
79 views

How to handle multiple space separator in Grass?

I try to load a Lidar point cloud in .xyz format to Grass (in QGIS 2.0.1). I tried to input the following options to the 'separator' field: tab, 'tab', '\t'. Just for the unlikely case that it ...
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0answers
38 views

Is there any GRASS command to measure the distance between a point in rastermap and another in vector map?

I have a question about WinGRASS 6.4.3. Is there any GRASS script command to measure the distance between a point in rastermap and another in vector map? I have a raster map and a vector map. Raster ...
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2answers
141 views

GRASS v.generalize method=douglas not working as expected

I'm frustrated with v.generalize trying to simplify polygons. Those polygons stem from ArcGIS's raster to vector function (imported into GRASS from Shapefile), so they are pretty zigzag like this: ...
2
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2answers
824 views

saga & grass configuration in sextante (ubuntu)

I have some trouble in running saga and grass algorithms in sextante. When I double click it appears a pop-up saying: Missing dependency.This algorithm cannot be run :-( This algorithm requires SAGA ...
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0answers
40 views

How to access nodes of a line network by using programming?

I have been given a manually digitized drainage (stream) network that needs ordering based on some rules (purely based on that single vector layer). I have built and cleaned the topology (removed ...
2
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1answer
138 views

Combining Geological Grids

I have a situation where I have 3 Geological grids, each showing a different horizon + the Seabed Grid. I need to extrude between these grids in order to make the 3D polygon for the geological ...
2
votes
1answer
157 views

GRASS - v.clean Conflation - How to snap a layer to a base layer

Someone told me in this post that GRASS GIS can handle multilayer topology, what I have not found any information about. I am not a specialist of GRASS GIS so I would need help with that if its really ...
0
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3answers
165 views

splitting a lines layer using points

I'm looking to accomplish a similar task to this thread: How to split a line at point positions? Using QGIS and the Processing and GRASS toolboxes available, I'm looking to split a vector layer ...
2
votes
3answers
1k views

Viewshed / Line of Sight analysis- as a batch process?

I wish to carry out a line of site analysis similar to the subject in here (preferably within QGIS): Visual Impact Assessment in QGIS or GRASS Scenario: I have two points, A and B. Point A is a ...
0
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2answers
181 views

GRASS algorithm r.los does not produce raster

After running the r.los algorithm through QGIS 2.0, I'm getting a 'Problem loading output layers' box which gives the following message: Oooops! The following output layers could not be open Output ...
0
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1answer
76 views

Error using “r.los” in QGIS

I am not a "computer person". So -- I don't know what this error message means. I found this question and answer for this same problem, but the solution did not work for me, dammit. GRASS algorithm ...
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2answers
302 views

How to interpolate a point vector layer inside a boundary (polygon layer) QGIS/GRASS/SAGA?

I have a to create a heatmap of water temperatures inside a lake for which I have sample points. The map should look much like the climate maps generated by climate change models. I have the ...
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0answers
37 views

problems using GRASS v.net and v.net.allpairs

I am using GRASS 6.4.3, and I am trying to use it to do network analysis. I have a line shapefile and a point shapefile, and here is my code(I take v.net.allpairs as my reference): v.net tc_bf25 ...
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0answers
13 views

problems using v.net.allpairs

I am using GRASS 6.4.3, and I am trying v.net.allpairs to do network analysis. I have a line shapefile and a point shapefile, and after I use v.net.allpairs, I type the command d.vect network, and I ...
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1answer
253 views

Calculate distance of points along a route QGIS

I have a line layer and a point layer, I need the distance between the first and the last point measured along the line. How can I do that using QGIS? Do I need to know linear reference? I don't ...
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0answers
36 views

“System not initialized. Programmer forgot to call G_gisinit().” message when loading table into GRASS via QGis

I am trying to load a CSV table into Grass with v.in.asciifrom the interface of Qgis 2.0.1 on Windows XP. As the progress bar indicated 74% of the data already loaded, I got the message "System not ...