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 do horton analyis on single catchment in grass gis

I have generated streams using r.stream.extract and used r.stream.order then I have tun r.stream.basin using inputs from r.stream.order. I am getting multiple basins. How to select a single basin and ...
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26 views

How to use GRASS v.kernel to calculate point densities along a network?

In a road network, I need to select the segments where a minimum of 5 dots occur (1 dot = 1 address) over a distance of 100 m (the image attached illustrates my question). I'm trying to use GRASS ...
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12 views

atmospheric correction using Grass

I am using i.atcorr for atmospheric correction in Grass6.4.4. I would like to add Landsat8 sensor to my project(build). If I copy the iwave.cpp file from grass 7, I get error messages. Do I need to ...
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9 views

GRASS7. Parallel import shapefiles failed

I am trying to import a 8 ShapeFile to GRASS V7.0.0. Each shapefile's size is between 80 Mb and 300 Mb. For this purpose, I've used multiprocessing in python. I run 4 parallel processes, each one ...
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10 views

64 Bit Win 8.1 grass 7 missing dependency

I searched for an solution but couldn't find it. Problem is: previous i had an working grass 7 within qgis 2.6/2.8 I know that there were more people with the same issue. When executing a grass 7 ...
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22 views

GRASS GIS Data display

I have import data vector and raster into GRASS GIS database. I try several projection and i dont know why i cant display the data in Grass GIS. But i can display my data with the grass plugin in ...
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1answer
33 views

How to calculate the 3D length of line segment in QGIS?

I've been looking through all of the GRASS commands in the QGIS 2.10 processing toolbox and it seems like one of these must be able to do this but I haven't found one yet. There is 'v.sample' which ...
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3answers
70 views

Grass toolbar for QGIS 2.10

I don't see the GRASS toolbar in QGIS 2.10 (Pisa). There are still GRASS commands in the Processing toolbox. I know there was some upgrade of GRASS for 2.10. Is the toolbar not available anymore? If ...
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41 views

What is the “t” in i.landsat.toar

I'm using GrassGis 7.0.0 for Landsat imagery. In the description of i.Landsat.toar under dos3 and dos4 is: TAUz = exp[-t/sin(e)] What is "t"? I cannot find any description about what it is. Can ...
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34 views

Identify nodes in GRASS

Apologies if this is a really basic question but I have been unable to sort this out: How do I identify nodes in GRASS? Specifically, I am running a Salesman analysis and get the following error ...
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35 views

Where is the “Add vector layer”-button in GRASS 6.4.4. plug-in QGIS 2.10.1?

I've just downloaded and installed the new version of QGIS 2.10.1 with GRASS 6.4.4. When opening a new GRASS mapset and importing layers, I missed the button "Add a new vector layer". I've updated ...
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34 views

Using GRASS7 algorithms via WPS - best practices

I need to set up Linux server (Debian or Ubuntu), which provide GRASS7 algorithms via WPS. I have some attempts with 52°North WPS, but without any success. Also there are many other ways how to do it, ...
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5 views

Error executing GRASS function i.topo.corr from R [closed]

I am attempting to topographically rectify Landsat data using the i.topo.corr GRASS function from within R using the rgrass7 package. My code is as follows: execGRASS("i.topo.corr", flags = "i", ...
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1answer
42 views

Is it possible to have v.in.lidar without compiling GRASS?

I already have installed libLAS like this: sudo apt-get install liblas-bin And Ì have installed GRASS GIS 7 from the ubuntugis-unstable repository. Is it possible v.in.lidar without compiling ...
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11 views

Importing raster data in to grass gis [duplicate]

0 down vote favorite I am using GrassGIS 6.4.2, How can i import raster data to GrassGIS without loosing RGB Values? raster image format is tiff, the below commmand is using to import raster image ...
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35 views

How can i import raster image to GRASS GIS without losing RGB Values?

I am using GrassGIS 6.4.2, How can I import raster data to GrassGIS without losing RGB Values? The raster image format is TIFF, the below commmand is using to import raster image: r.in.gdal ...
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40 views

how to orthogonalize building outlines

I'm looking for a way to orthogonalize building outlines which I've extracted from a high-res DEM. I'm using the FOSS GIS stack (QGIS, GRASS, SAGA, PostgrSQL, PostGIS) and can code in Python (or ...
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37 views

Elevation data from 3D shapefile of buildings to raster DEM

I have acquired LoD2 building models in the 3DShape format (Polygon ZM). This LoD2 data needs to be prepared for a R-script of solar irradiation calculations on roof surfaces, but which can only ...
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2answers
68 views

Suitable Raster processing methods to extract field boundaries from images

I'm trying to extract field boundaries and features from a lot of aerial images of agricultural land - and avoid digitizing these features manually. I've managed to get a crude raster file of the ...
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1answer
42 views

What's difference between Topology and Check Validity in QGIS?

I would like to know what the difference is between the Topology Checker and Check Validity tools? Is there anyone who knows of a good document or tutorial that explains functions of these tools? ...
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28 views

QGIS Convert bathymetry shapefile from fillable to strokeable

In Java I would like to stroke the bathymetry depth lines instead of filling the area. I'm starting with the Natural Earth Bathymetric Data: ...
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72 views

Grass 7 no longer works via the Processing Toolbox in QGIS

When I try to execute a Grass 7 algorithm via the Processing Toolbox in QGIS 2.10, 2.8.2 or 2.8.1, I get the following error: Missing dependency. This algorithm cannot be run :-( QGIS ...
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1answer
46 views

How do I count the number of vector lines that pass though a given raster cell?

I am working on a project (currently in GRASS7 though I'm not against exporting to Arc or R or other software if necessary) where I am generating thousands of shortest cost paths (using the r.walk and ...
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15 views

QGIS Training Manual - Lesson 12.2.1 (GRASS GIS) - r.colors.table module does not color raster

I am going through the QGIS Training Manual, Lesson 12.2.1 ("Follow Along: Set Raster Colors) and noticed that the 'r.colors.table' GRASS module did not color my DEM raster layer which I imported via ...
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27 views

Simplify / generalization of flow lines

I'm trying to make a model of surface runoff of rain water. I'm using GRASS GIS function r.flow, which generates nice smooth lines of runoff. What I need is edit these flowlines someway to avoid ...
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42 views

Compile QGIS from source (with Grass)

I recently decided to reinstall QGIS and build against the latest version of GDAL - something I have been putting off for ages because I suspected it would be a nightmare. Lo and behold it has been, ...
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1answer
54 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 ...
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10 views

GRASS problem - r.viewshed.cva addon

I'm a very beginner at GRASS. I'm using GRASS 7.0 and I tried to install r.vieshed.cva extension. When installed, if I type it in the command line, it appears "r.viewshed.cva" is not recognized as ...
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2answers
68 views

GDAL/QGIS broken Ubuntu 14.04

I think I've managed to bust GDAL after (I think) installing Grass7. I had previously built GDAL (1.10) from source with a bunch of additional drivers. When installing Grass7 GDAL 1.11 was installed. ...
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11 views

Grass 7 import shapefile problems

I'm just messing about with Grass 7 (installed fine on Ubuntu 14.04 - well no errors at least). I'm trying to import a shapefile using v.in.ogr and when presented with the dialog box, browse for my ...
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189 views

Create raster with grid cells values based on area covered by polygons

I have a polygon data with area covered by the forests (data is here - https://www.dropbox.com/s/zgckliydalljw6a/sp_data.zip?dl=0). I want to convert polygons to raster. The value of each grid cell ...
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GRASS r.inund.fluv example of input files

Does anyone have an example of input files for the GRASS r.inund.fluv add-on that can be shared. I am asking because I am getting some errors when I am trying to run an the files that I created and I ...
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52 views

Removing pseudo-nodes using QGIS Sextante plugin?

I have a road network (vector) that i'm interested in carrying out some space syntax analysis on. Predictably my GIS data is in a pretty terrible state. For example, there are a bunch of roads on the ...
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38 views

Converting a (WAsP) vector map to a raster map with GRASS GIS

i'm quite new to GIS and i need to convert roughness data which is available in a vector format to a raster format. The final data should be on a simple 2-dimensional uniform grid with a constant grid ...
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1answer
16 views

Creating input node file for V.net.salesman in GRASS?

I have imported line vector layer and point vector layer(12 points) to grass using v.in.ogr. Now i want to use v.in.salesman to find shortest path between these 12 points, but i couldnt input ...
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40 views

registering MODIS in GRASS as space-time dataset

I have a problem using the space time module in GRASS GIS (7.1 for Ubuntu). I have a MODIS time series with 8 day interval, so 46 images per year. So I created a file (filelist_grass.txt) containing ...
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50 views

Drawing “proportional” buffer using QGIS or GRASS?

I'm working on aquatic vegetation and have a shapefile representing floating vegetation in a lake. By some studies, we know that submerged vegetation extends for a certain extension based on floating ...
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49 views

Why is r.sim.water out of memory (ERROR: G_calloc) in GRASS GIS?

I'm having trouble with GRASS GIS. I'm new to GRASS GIS, I have played around and also searched the internet and the Wiki, but found nothing really helpful, so this is my last chance :) I wanted to ...
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59 views

Error: GRASS 7.0 and QGIS 2.8.1 in Linux Mint from the ubuntugis-unstable

I have installed GRASS 7 and QGIS 2.8.1 from the https://launchpad.net/~ubuntugis/+archive/ubuntu/ubuntugis-unstable (Trusty 14.04) in Linux Mint 17.1 64bit(sudo apt-get install postgis libgdal1h ...
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33 views

GRASS 7 (python:14221): Gtk-CRITICA Linux Mint

I installed GRASS 7 and QGis from the https://launchpad.net/~ubuntugis/+archive/ubuntu/ubuntugis-unstable (Trusty 14.04) in Linux Mint 17.1 two weeks ago (sudo apt-get install postgis libgdal1h ...
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1answer
36 views

How can I create polygons for a 3D map from a DEM in grass/qgis

I have a SRTM 30m DEM of my area. I want to create a physical 3D terrain map from it (from felt, 3D printer, you name it). I have two questions about this process: With grass r.contour I created ...
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1answer
25 views

Error when installing a GRASS addon!

I am trying to install r.inund.fluv on Linux to produce inundation maps but I am getting the below error. Note that I have a Fortran compiler. Any help with this matter would be highly appreciated. ...
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2answers
40 views

How to use r.mapcalculator to change values within a raster cost map to negative

I have created a cost map in r.cost module in GRASS (through QGIS). This is actually a distance map from a protected area and distance from protected area has been calculated in both directions. How I ...
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1answer
39 views

GeoTiff exported using GRASS will not open in other programs

I am trying to export an image group as a multi-band GeoTiff using the r.out.gdal module in GRASS. For some reason I cannot get ArcGIS to recognize my GeoTiff exports. I have tried opening the file in ...
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28 views

Linearising aspect in GRASS GIS

After having produced aspect of surface in GRASS GIS and being aware that GRASS GIS calculates aspect counterclockwise from east, how could we transform aspect from being a circular variable (0-360 ...
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21 views

Mod function in GRASS GIS

What is the equal of ArcGIS Raster calculator "Mod" function (Finds the remainder of the first raster when divided by the second raster on a cell-by-cell basis.) in r. mapcalc in GRASS GIS?
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31 views

Execute GRASS command within qgis phython console

We try to calculate catchments with the r.water.outlet function from python console. To do so we use the following code: import processing rlayer = QgsRasterLayer("/my/path/DrainageDirection.tif", ...
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46 views

Convert manual colored maps to vector

Is there a way to colorimetrically and automatically vectorize georeferenced rasters that came from manually colored, scanned maps? Currently we Print the topography maps 20k scale --> hand-coloring ...
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48 views

From Landsat spectral radiance (W/m2*sr*µm) to Global horizontal irradiance (W/m2) for mere mortals

We are working in a solar energy project to locate potential sites for solar panel farms. We are using the Landsat 7 panchromatic band to derive radiance with GRASS using i.landsat.toar (W/m2*sr*µm ...
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26 views

comparison of atmopsheric correction methods

I have noticed that dos methods for atmospheric corrections are in the section of radiometric correction (i.toar) on grass gis.Does that means that dos is a method doing radiometric and atmospheric ...