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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Interpolation of contours (from one “main-contour-shapefile”)

I calculated, that the best and smalest possible äquidistance (equidistant) for my map is 30m. After I generlized my DHM, I extracted contours of a intervall of 30m and smoothed them. Now I have my "...
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How to convert a regular point grid to raster? [duplicate]

Possible Duplicate: How to convert a point grid to a raster? I´d like to convert a regular grid (25 meter) of points (XYZ) to a raster. I have tried the GRASS-tool r.in.xyz but I always get a ...
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How to rasterize a vector map?

I am looking for a way to create a raster grid from a vector map. I have a map consisting of shapefiles which I want to export as a raster with UTM coordinates. I was thinking of something using the ...
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Grass Gis 7 does not start in OS X 10.11 El Capitan

Recently I installed the El Capitan upgrade but unfortunately Grass 7 (from the official repository - Grass Gis for Mac) does not start any more. I also re-installed all required frameworks, but I had ...
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611 views

Saving Command History/Outputs to a file - GRASS

Is there any way to save the commands typed and the outputs obtained in terminal under GRASS GIS to a text file? I have read that GRASS saves history for each mapset but I have no much idea about how ...
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Moving raster to different mapset GRASS GIS

I have a raster DEM that I created in one mapset but I would like to copy it to another mapset for another purpose. Is this possible within GRASS or can I just copy some files over in the ...
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How to install add-ons in GRASS?

How do I install the r.inund.fluv script in GRASS? https://svn.osgeo.org/grass/grass-addons/grass6/raster/r.inund.fluv/
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How to do Kernel density analysis in QGIS 1.7?

Do someone have some suggestion? We would like to tray Kernel Density analysis as we did with ArcGis using QGIS?
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Error when creating a new mapset with GRASS in QGIS

When I try to create a New Mapset with the GRASS plugin in QGIS I get an error or the program crashes. QGIS 2.6.1 (32-bit install, Win7). QGIS crashes completely when clicking "Finish" in the New ...
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245 views

Programmatic raster-vector calculation

I currently use GRASS' r.mapcalc to find the difference between vector and raster data using a loop and temporary files and layers. Is it possible to do the core calculation between raster with a ...
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425 views

95 percent volume contour

I generated, from point data, a kernel density map using GRASS, and I would like to identify the 95% volume contour in it. Is it possible in GRASS? Thank you
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131 views

v.kernel is missing under Processing Toolbox GRASS GIS 7 commands

I installed the QGIS Standalone Installer Version 2.14 (64bit), that automatically contains GRASS 7.0.4. I created a map with several layers and rasters in the program called QGIS Desktop 2.14.3 with ...
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1answer
2k views

Convert shapefile lines to a polygon in GRASS

I have a shapefile of a map that is the outline of a number of islands. I would like to convert the lines into polygons (ie all islands filled in) using GRASS. I searched on how to do this with GRASS ...
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5answers
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Elevation correction ASTER GDEM2 (+10m)

My ASTER GDEM2 has a average elevation error of -10m for my area. (I testet it using 90 defferential GPS reference points and compared it with old Topo25, SRTM, and GoogleMaps). I would like to ...
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1answer
155 views

Issue with Sextante r.map calculator and modeler

I am trying to build a model with Sextante modeler and the r.mapcalculator algorithm but when I run the model I get the error message: ‘Could not load layer: ‘….’Check sextant log to look for errors ...
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664 views

How to reproject a raster to Winkel Tripel projection?

I'm trying to project a raster map (in ASCII grid format) from longlat to the Winkel Tripel projection. But I'm running into errors, for instance gdalwarp won't accept the proj-string. $ gdalwarp -...
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1answer
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How to get custom colormap onto 3D NVIZ in QGIS GRASS

I am trying to create a 3D version of my 2D raster using QGIS GRASS NVIZ. I have been following these steps: http://linfiniti.com/2010/12/3d-visualisation-and-dem-creation-in-qgis-with-the-grass-...
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2answers
935 views

georeference and orthorectification of aerial photos

I am trying to process photos taken with a tetracam ADC micro camera placed on a UAV. I have GPS coordinates and mavlink logs providing roll, pitch and yaw of the UAV. I am having a real hard time ...
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89 views

R.Neighbors with large neighborhoods?

I'm running into problems running the r.neighbors GRASS command in QGIS. Although it will run for small neighborhoods as soon as I increase my neighborhood above a certain number it becomes unbearably ...
3
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1answer
78 views

Convert xyz points to topography and calculate mean slope

I am working on point data (x, y, z) in meters from origin. I have between 24 and 35 points for each plot (10mx10m), with random locations. I would like to modelise topography over the whole plot in ...
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3answers
2k views

How to access vector coordinates in GRASS GIS from python?

Is there a way to iterate over lines and their vertices using python? I'm new to GRASS GIS, and it looks like there are ways to read raster (for numpy), but I don't see a direct way to access ...
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1answer
738 views

How to get the Flow or directional raster map using GRASS?

Aside from using r.fill.dir in GRASS, is this the script to produce the Flow or directional raster map? Is the output for the script the following graphic? http://grass.fbk.eu/grass63/screenshots/...
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1answer
736 views

Where to change GRASS GIS wxGUI language?

I use GRASS 6.4.2 on Russian version of Windows 7 x64. As I start wxGUI it is shown in Russian. But I don't like its translation and want to work with English interface. I have no clues how to solve ...
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2answers
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How to set output resolution for gdalwarp to that of source file?

I have a large raster, which I want to re-project and crop for a new location that I'm creating in GRASS. I seem to have gotten the re-projection and cropping right with this call to gdalwarp: ...
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577 views

How to fix unreachable nodes in QGIS GRASS network?

I have created a network with the GRASS module v.net. But when I try to create the travelling salesman path with v.net.salesman, I get: Destination node 9383 is unreachable from node 9398 If I ...
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1answer
2k views

GRASS GIS: How do I run a batch (bash?) script?

I am in a GRASS database (in command shell), where I want to run a loop function. For example, I want to do an operation on many raster files that are in the database. I know this must be done through ...
3
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1answer
629 views

How to make a transparent background image using r.out.png?

Can the white background of the r.out.png of GRASS be changed to transparent?
3
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1answer
613 views

spgrass6 and GIS_LOCK

I would like to thank's everyone first, i learn a lot here (gis.stackexchange) about GIS. I have one question about the use of GRASS within R session, i'm able to do some basic task, but i have one ...
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2answers
420 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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1answer
784 views

Visualizing a LiDAR point cloud in 3D with GRASS?

I'm new with QGIS and GRASS so I'm sorry if there is a straightforward answer for this question but I can't seem to get it done. I've imported a point cloud into QGIS from a datafile. Now I'd like to ...
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1answer
209 views

How to change the raster color range in GRASS NVIZ?

I'm trying to create a 3d map in GRASS NVIZ from a GDEM (raster) and the range of colors that show the height of the terrain are very ugly, how I can change them? For example, I would like the low ...
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1answer
82 views

How to define measurement units in grass

I need to get the length and area of some landscape features in the US. My data was in lat and long degrees. I created a new location with an UTM projection and read the data into grass. Now if I ...
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2answers
61 views

GRASS 7 environment setup for Python

I would like to use some GRASS functionality from a Python programme. With GRASS 6 this required the set up of various environment variables, as detailed in the GRASS Wiki. I am trying a similar ...
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2answers
267 views

QGIS 2.14.1 Processing Toolbox GRASS 7 .NVIZ Not working

I have a problem with the command GRASS 7 .nviz in QGIS 2.14.1 installed through QGIS-OSGeo4W-2.14.1-1-Setup-x86_64.exe.md5sum all GRASS commands work exept .nviz / nviz7 images: I test with ...
2
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1answer
2k views

What am I doing wrong with QGIS v.clean?

I thought I understood how the GRASS v.clean tool worked in QGIS (in 2.6.1 Brighton) but I keep getting unexpected results and errors with a polygon ShapeFile. I've run the QGIS TopologyChecker with ...
2
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1answer
129 views

Processing algorithm fails from Python script

I'm trying to write a Python script performing a geoalgorithm. What is surprising me is the following: I first test the algorithm by QGIS (2.8) interface. In my case, the GRASS interpolator v.surf....
2
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1answer
307 views

Extracting polyline of border between differing polygons using R or GRASS?

I have a shapefile with polygons with an associated variable that can take different values. I would like to extract the borders between polygons of differing value (red and blue) as a polyline (dark ...
2
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1answer
89 views

Quantile in QGIS python Plugin

QGIS is very powerful when it comes to styling Vector Data. When it comes to Raster data, ArcGIS still has some advantages including Styling based on Quantiles. See my earlier post: For this I want ...
2
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1answer
341 views

Using Spyder IDE to develop python for Grass GIS, get 'ImportError: No module named grass.script'

I am trying to use Spyder IDE to develop a python script using python library from grass-6.4.3. I run the script below, and get 'ImportError: No module named grass.script' I am using python 2.7, ...
2
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1answer
603 views

How to import SpatiaLite data into GRASS?

How can I import SpatiaLite tables into GRASS? Are there any restrictions I should be aware of? How does GRASS cope with columns that don't have a specific type (Sqlite tends to create such columns e....
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2answers
489 views

GDAL-GRASS building fails

When I run ./configure --with-grass=/usr/local/grass-6.5.svn/ I get the following errors: .......... checking for gdal-config... /usr/bin/gdal-config using /usr/lib/gdalplugins as GDAL shared library ...
2
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1answer
792 views

Integrated viewshed analysis

I need to do integrated viewshed analysis of a target with several observer locations. I am going to use r.viewshed analysis function in GRASS. With this function, it is possible to perform analysis ...
2
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1answer
1k views

How to invert polygons (or other options for exterior styling)?

I have a shapefile containing many polygons that I want to use to mask a raster. I have tried gdalwarp -cutline <shapefile> -crop_to_cutline -srcnodata -9999 -dstnodata -9999 <source_raster&...
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2answers
3k views

How to set cell size for vector to raster conversion in QGIS GRASS plugin?

I'm converting a vector (loaded in GRASS plugin in QGIS (1.7.0.-wroclaw) and would like to convert this to a raster with a defined cell size. At the same time I need a value from the attribute tabel ...
2
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1answer
417 views

Problem importing LiDAR data in GRASS 7

I compiled GRASS 7 on Ubuntu 12.10, with liblas in order to run r.in.lidar and v.in.lidar. I now want to import .las data; the option in file -> import raster data -> LAS LIDAR points import is given ...
2
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1answer
404 views

OGR Python bindings

When I try to access one of the GRASS vector files through Python OGR bindings, it gives error: Here is the script code in Python 2.7.3 IDLE (GUI) in Windows 7. from osgeo import ogr ds = ogr.Open('...
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2answers
995 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
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2answers
3k 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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2answers
60 views

i.landsat.toar not working and returning error [duplicate]

First time using grass. I need to convert DN to reflectance. Imagery -> Sat. images tools-> i.landsat.toar. But when I add raster name. I get error. Im using landsat 8 images WARNING: WARNING: ESUN ...
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243 views

How do I install mdenoise in GRASS?

How do I install mdenoise in GRASS 6.4.3? I've already successfully installed r.denoise, and have downloaded mdenoise from wget http://www.cs.cf.ac.uk/meshfiltering/index_files/Doc/mdsource.zip. How ...