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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How to change GRASS language within QGIS?

I use GRASS plugin inside QGIS on Japanese version of windows 7 x64. As I start GRASS tools, all the content show in English but when I try to execute a tool, tools option dispalys in Japanese ...
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55 views

Export GRASS raster as GeoTiff : nodata values exported as -nan (what happens in R?)

I am using the package raster to work with GeoTiff raster files which I expoerted from GRASS using r.out.gdal. GRASS assigned the value -nan to some raster files (type FLOAT32) for missing values. ...
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83 views

Can QGIS or GRASS convert layer files to shapefiles?

Should I be downloading QGIS or GRASS? I want the program with the most features. Most importantly, I have a lot of .lyr files. Can either of these softwares convert to shp and if so, how can I do ...
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3answers
70 views

Discrete Waterpoints with Grass

I've been working with Grass GIS for about two months. I have to develop a method for the identification of target regions of small hydropower plants. Boundary conditions are a predetermined minimum ...
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14 views

GRASS GIS: Network analysis doesn't work correctly

I got a problem with the Network Analysis function v.net.iso in GRASS. I tried it so many times but the function doesn't work correctly. I tried to calculate isolines via the function v.net.iso, based ...
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27 views

Raster Mosaicking GRASS Issue

I have a project where I have to download DEMs from USGS and mosaic them. So I downloaded them from EarthExplorer and imported them into GRASS. When I start the GUI version of r.patch using the ...
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77 views

Is it possible to generate a boustrophedon pattern which fill a vector Region with GRASS?

Every thing is in the title... I have a vector region in GRASS. And I would like to generate a vector (a polyline) beeing the bostrophedon pattern which fill this region. In the picture bellow, I ...
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2answers
512 views

LANDSAT 8 i.landsat.toar error GRASS 7

I am a bit new to GRASS, but I have managed to get a lot of good work done thus far. However, the following error is really throwing me off, because I can't find any help anywhere for it. I am using ...
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14 views

r.watershed outputs different depending on use of console and toolbox

I am returned two different outputs despite same input parameters from r.watershed depending on whether I run it from the console or from the GRASS toolbox. The threshold for both is 5000. They both ...
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14 views

r.water.outlet returning blank raster

I am trying to delineate a watershed using r.water.outlet. I have created a flow direction raster using r.watershed (threshold = 50) (cell size is 300m). I use this flow direction raster in ...
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42 views

many add-on don't works GRASS 6.4.3

I use GRASS 6.4.3 on windows 7 64 bit. GRASS has been installed with QGIS 2.6.1. I have added r.stream.* adds-on by SVN. For each add-on, messages of installation were : OK. But when I try the ...
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2answers
61 views

r.in.xyz doesn't work in GRASS

I have these LIDAR data *.xyz files (1st col x, 2nd col y, 3rd col z) 485000.16 6508997.48 1.84 485001.27 6508998.92 1.86 485001.02 6508996.68 1.85 485000.77 6508994.45 1.79 485000.52 6508992.19 1.79 ...
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1answer
34 views

Draw lake isobaths having depth points and coast line

For some lakes, I have a line shapefile representing the coast line and some points with many information, among which depth (in meters). Is there a way to draw an isobath linking every point with the ...
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1answer
42 views

Raster import from GRASS to R - handling nan/NA

I have several doubts, so I will try to be as clear as possible... thanks for your understanding. I am generating a regression model using several environmental covariates. Before importing the GIS ...
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37 views

Displaying a Digitial Elevation Model using GRASS GIS draped by an RGB Raster

I have the following: Digital Elevation Model from SRTM LANDSAT Imagery from the same area I wish to display the DEM draped with the raster band combination (3,2,1) using GRASS GIS. My ...
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1answer
210 views

Pan sharpen Landsat 8 using Grass 7

I have followed this great tutorial on pan sharpening using Grass GIS 7 (I'm using beta 3). Everything in the tutorial seemed to have worked, but my final output is not as expected (pictured below). ...
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47 views

i.landsat.toar doesn't Work With Band 6 of Landsat 7 in Grass 7

I'm facing an issue when running i.landsat.toar with a Landsat 7 image, here's the list of files: LE70010752014040CUB00_B1 LE70010752014040CUB00_B2 LE70010752014040CUB00_B3 LE70010752014040CUB00_B4 ...
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1answer
33 views

Unable to find a specific GRASS add-on in QGIS

I would like to use the r.xtent add-on made for GRASS GIS (http://svn.osgeo.org/grass/grass-addons/grass6/raster/r.xtent/description.html) in QGIS using the GRASS plugin, but I can't seem to find it. ...
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1answer
84 views

It is possible to verify landsat reflectance values?

My question is really wide today, as I am still beginner in Remote sensing. I´ve asked a GRASS programmer to prepare for me Landsat reflectance values from raw DN values (1 scene per year from 1987 to ...
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3answers
4k views

New QGIS install can't find GISBASE

At QGIS startup I get the message: "QGIS couldn't find your GRASS installation. Would you like to specify path (GISBASE) to your GRASS installation?" (Windows 7) No amount of rooting around the ...
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1answer
96 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 ...
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49 views

Calculate shortest path not on land but over sea

I wonder if someone can give me some advice on how to calculate the shortest path between two points, not over land but over sea. I know that I will have to take in to account the magnitude of sea ...
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3answers
1k 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
407 views

libgdal1 and libgdal1h conflict

I am on Ubuntu 14.04. When I am installing PostGIS-2.1, it's asking for libgdal1 library. But when I am installing libgdal1, it's removing grass and gdal. Can someone please guide me how to install ...
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316 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 ...
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78 views

Error when using r.watershed

When i am calculating LS Factor using Grass r.watershed the error "Raster map or group not found" (image below) keeps turning on. I don´t understand why this error happens if i am using a elevation ...
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41 views

3D interpolating

Our final year project domain is soil contamination modeling. We collected soil samples at the depths of 0.3 cm ,0.5cm , 1cm , 1.5 cm in about 25 locations. We considered 8 contaminants- p h, sodium, ...
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1answer
187 views

QGIS 2.6.1 Brighton/ Grass pluggin r.stream.xxxx

I just updated my OSGeo4W and now have QGIS 2.6.1 and GRASS 6.4.4 and am trying to get strahler stream order. I am figuring out GRASS 6.4.4 GUI by itself but GRASS is easier withing QGIS, however, I ...
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3answers
2k views

How to reclassify a float raster?

I have three rasters which represent distance (in metres) from certain things (bus stops, parks, libraries). I would like to reclassify these rasters so that they get integer values based on the ...
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53 views

QGIS and GRASS r.fill.dir processing times

I am new to the open source software and have performed analysis in ArcGIS in the past. I am learning as I go on this processes for OS. I am trying to calculate stream order (strahler) on a 1 gig ...
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5k views

Converting Shapefile to MySQL?

I have used Grass GIS imported a .shp file; I now want to export this file to MySQL. I understood that MySQL will contain the function of all three the files necessary in a Shape file system (.shp - ...
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1answer
1k views

GRASS v.Overlay/QGIS Intersect Speed intersecting line and polygon

Im currently trying to convert my scripts from ArcGIS to QGIS but one aspect that is extremely slow (imo) is trying to intersect a polygon with a line feature. I feel as though there must be a better ...
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127 views

r.stream.* commands do not work in qgis environment

I have been working for a while with some grass commands in QGIS environment (r.watershed, r.terraflow, r.thin, r.to.vect etc) with out any problem. I haven't been able to get any results at all from ...
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2answers
2k views

How to compute parameters for QGIS Affine transformation?

I have a vector floorplan (DXF) that I've added to a blank project in QGIS using the Dxf2Shp plugin. I've been reading tutorials and StackExchange threads, but I can't seem to find out how to ...
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1answer
95 views

GRASS plugin absent from QGIS 2.6 OSGeo4W install

I've just installed QGIS 2.6 Brighton using the OSGeo4W installation. The GRASS toolbox plugin has not, however installed as it had been with previous versions. Before, I was able to access the GRASS ...
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1answer
65 views

How to reposition a polygon Shapefile using ground control points and v.rectify?

I'm new to Grass. I would like to reposition a polygon shapefile using ground control points and v.rectify seemed just the perfect tool to do that. The raster from which the shapefile comes from was ...
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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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2answers
136 views

QGIS GRASS shell commands not working in Yosemite

First time asking a question here. Running GRASS 6.4.3 within QGIS 2.4.0 on Mac OS 10.10 Yosemite. I'm trying to run v.net.iso within the GRASS shell, but the following error is returned every time: ...
2
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1answer
56 views

Python library for geometrical calculations using with GRASS GIS?

I have to do some geometrical calculations in 2D(point, lines, line segments and intersection points) in Python, and then use it in GRASS GIS. What is the best library to use for it? I'm trying with ...
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1answer
33 views

to remove location of grass

i wan to delete the Location of a data set in grass gis 6.4.4 using grass command. For customizing grass for our data set, i need to load different location and mapsets of different regions of ...
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125 views

Empty signature file after i.gensig in GRASS

I'm trying to make a supervised classification in Grass 6.4.3 under Linuxmint 16. After digitizing the training areas, I transformed them from vector to raster. Then I've done the following: just in ...
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0answers
104 views

Import vtk file in grass gis

last summer I made the relief of a cave, and at this time I returned with Therion software. This survey is in 3d and I can save it in the formats .Lox, .3d, vtk. I would like to import it in grass or ...
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70 views

Extract representative slope profiles from hillslope polygons

With the help of the Whitebox Geospatial Analysis Tools I was able to easily extract hillslopes from a river network in combination with a flow direction map. Now I would like to extract ...
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21 views

r.massmov GRASS Addon execution error

I'm a rookie Grass7.0 user, and I am having a problem in executing the r.massmov addon. After installing r.massmov through the graphical user interface (Menu - Settings - Addons Extension - Install), ...
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18 views

importing to tif

i am working on grass 6.4.4. i want to know the details of which GDAL version grass is using.i want to use r.in.gdal.exe which is giving "no dlls found in water fall model" error message.remaining ...
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1answer
351 views

how can i correct atmospherically landsat 8 images?

I am trying to correct atmospherically an image from Landsat 8 with 6s model from grass 7 and 6.4. Because there are no parameters for Landsat 8 yet, I am trying to give parameters from Landsat 7 ...
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1answer
41 views

Delination of half basins or hillslopes from a flow direction map or/and a stream network

I am using the GrassGIS r.stream.extract extension to delineate a stream network with the options 'mexp' (Montgomery exponent) and 'd8cut' (Use SFD above this threshold). It works perfect so far and ...
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1answer
85 views

Problems using r.reclass in QGIS: invalid reclass rule error?

I need to reclass some rasters, but i am having a couple of problems, i can´t generate a new raster with the reclassification using the r.reclass of GRASS. For the question here i´m using as example ...
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1answer
28 views

Calculate raster mode with r.mode - problem with decimals

I am working with a raster file that represents the percentage of vinyards by commune (e.g., municipality) in a region in France. The statistics were calculated for each commune based on surveys from ...
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14 views

Calculate r.mode and r.univar with active MASK

This may be a very stupid question, but I am new in GRASS. I am calculating summary statistics with r.univar and the mode with r.mode. I have an active mask which differentiates agricultural from non ...