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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v.clean batch process withing QGIS 2.10 (PISA)

I get an error message when i try to creat a batch for v.clean operation.. Algorithm v.clean - Toolset for cleaning topology of vector map. starting... local variable 'filename' referenced before ...
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58 views

What are the meaning of Grass drainage direction values from r.watershed

In Grass r.watershed the D8 drainage directions generated from r.watershed are -8. -6.-4.-2, 2, 4, 6, 8 (-1 No Data) What actual directions are these? For example in ArcGIS I know 128 is up and so ...
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1answer
28 views

Panchromatic Image Classification GRASS GIS

How to perform an unsupervised classification of a single panchromatic satellite imagery in GRASS GIS? I tried it many times but I keep being prompted for a second image or other images in the ...
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1answer
54 views

v.kriging Addon not installed - GRASS GIS 7

I am using GRASS GIS 7. When I try to install "v.kriging" module using "g.extension" command, it is not installed. Though it says that the extension is successfully installed, I get the error ...
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44 views

can grass gis module be used in parallel mode

i want to use my customized grass gis(6.4.3) module for separate bands of a sensor in a parallel mode. is it possible? i have created separate location and if one band is executed ,for the second band ...
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25 views

Is there a lower bound on the std deviation for v.kernel in GRASS?

I'm using the v.kernel function in GRASS to create heat maps. I am able to generate an acceptable heat map using a std deviation of .2 and a several thousand rows and columns. After the map is ...
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2answers
36 views

GRASS GIS - Plot Legend using Text Only Version

If a person uses the text only version of grass on a remote system, how do you output the legend as a graphics file? such as: r.out.tiff input=mymap output=file.tiff but have it print the legend ...
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85 views

How to make DEM raster in Google Sketchup?

I would like to make DEM in google sketchup, later add 3D buildings and finally convert this file to raster. Afterwards, I want to import this raster to GRASS GIS to make solar maps. It is possible to ...
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1answer
91 views

Find lakes on an elevation raster

I would like to know if there is a way to identify lakes based on an elevation raster (like SRTM or ASTER)? As far as I can understand, it would mean identifying any cell below the elevation of ...
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1answer
41 views

Errors while building grass-7.0.1 with Msys/MinGW

I need to build grass-7.0.1 for qgis on Windows 10 with Msys/MinGW. I succefully installed all packages from general and several packages from optional requirements. Here is my configure options ...
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80 views

What does v.distance calculate excactly?

As I am from an economics department, I am quite a beginner in QGIS. I read, that if I wanted to calculate the distance from a polygon to a point/line/other polygon, I should use the GRASS plugin ...
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1answer
140 views

How do I open GRASS layers in QGIS

I'm quite a newbie to QGIS and GRASS.. I have installed QGIS 2.10.1 with GRASS 6.4.3 on my Windows 7 laptop and wish to open GRASS layers in QGIS. If I got it right, you can use the QGIS built-in ...
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91 views

How to merge vector buildings height layer with raster DEM to get solar maps in r.sun in Grass GIS?

Welcome, this is my first post. I have vector layer with buildings heights and vector/raster DEM file. I need to create solar maps with sun radiance values on the roof (and on surface, ofc). I am ...
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1answer
54 views

GRASS mapcalc in Python Shell

I'm trying to convert my GRASS/Bash script into the Phython Shell. Now I have a raster dataset (test.01) which I want to convert in 1 or 0. In GRASS I used the command r.mapcalc r.mapcalc ...
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55 views

Speed optimization of shadow computation with grass gis r.sun

I am trying to optimize the speed of r.sun to compute shadowed area on a DTM at 1m resolution. My current area is 3.39 km² but my final area will be 450 km². The r.sun wiki say that pre-computing ...
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1answer
40 views

Visible altitude across a raster from a point

I have a raster surface model and I'm trying to determine the height an object would need to be at to be visible from an arbitrary point at an arbitrary altitude. I am currently using Grass and have ...
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1answer
45 views

How do I get the distances to every cell in GRASS?

I have an elevation raster map, a point, a raster map defining the viewshed from that point, and now I want to produce another raster map with the results of a function of the distance between the ...
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1answer
94 views

GRASS 7.0 fill.dir crash

I am working on a 13407 lines * 11050 columns raster file (SRTM DEM, 30m) with a script that calls a series of hydrological modules in GRASS 7.0. The system I am using is a Windows server 2012 R2, 64 ...
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1answer
50 views

2.10 program group option to open QGIS with GRASS

I have installed QGIS 2.10 on Windows 8. I cannot find the 'option' to start QGIS with GRASS - as has been previously answered. Have I possibly missed something in the install? Is this 'missing' ...
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1answer
57 views

Paths with least elevation gain

I have a DEM of a city with numerous hills and a shapefile of the city streets. I want to find the five paths from a low point A to a high point B on the street network that involve the least ...
2
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1answer
41 views

Return variable with GRASS GIS on a Windows machine

How do I return a variable in GRASS GIS on a Windows machine? For example I set a list of files to define my region. I already figured out that I can't use the bash command export, I need to use set ...
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2answers
209 views

Deciding variables for unsupervised image classification?

The results of an unsupervised image classification may vary A LOT depending on the variables you use from the beginning. These are the variables for the tool in ArcGIS:number of classes, minimum ...
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1answer
58 views

reading GRASS vector map in python

I know similar questions have been asked several times, but none of the solutions seems suitable for my problem or don't work.. I computed flowlines using the r.flow tool from GRASS GIS, then I ...
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130 views

Module nziv not found in QGIS 2.10.1-Pisa

I want to use nviz in QGIS2.10.1-Pisa on windows 7 and I always get the same warning message : "Module nviz not found", whenever I click on it in the GRASS tools Modules list. I have tried to ...
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49 views

“Identity” equivalent in Grass GIS

In ArcGIS and SAGA GIS there is the "identity" tool, which creates a vector overlay and shows area contributions of polygons in shapefile B to the polygons in shapefile A (in the attribute table). ...
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1answer
106 views

GRASS plugin for QGIS2.10 missing [duplicate]

I have installed installed qgis2.10 from source on Centos6.6 however the issue i'm facing is that i am missing the grass plugin form the gui. I have checked the plugin manager, its not listed there. ...
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50 views

export several rasters from grass

I'd like to export 127 raster files from grass to .tif in one operation. I already stumbled over this post How to batch export using r.out.gdal command in GRASS but it doesn't work (I don't even know ...
2
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1answer
130 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, ...
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1answer
69 views

QGIS GRASS raster to GeoTiff

First of all: Windows 8.1 QGIS 2.8.2 Wien My problem is that I used the GRASS module r.watershed to delineate watersheds and get flows with a DEM. It worked fine so everything is OK so far. But ...
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1answer
90 views

Can't access GRASS tools in QGIS [duplicate]

I'm running QGIS 2.6 on OSGeo-Live 8.4 Virtual Machine based on Lubuntu 14.04. I've set up a GRASS (GRASS GIS 7) environment in QGIS, and I have a merged .tif file of LiDAR images open in QGIS, so I ...
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1answer
238 views

QGIS 2.10 with ubuntugis dependecies Grass issues Ubuntu 14.04

I saw in How to correctly install QGIS 2.8.3 with GRASS plugin on Ubuntu 14.04? how to get Qgis 2.10 running from the non ubuntugis repository with grass features but I'm still having problems with ...
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7 views

Sky View Factor of building roofs => Vector algorithm [duplicate]

I'm currently working on a project in which I'm trying to assess the SkyViewFactor of a given roof using building vector data. I've already managed to build a process based on vector rasterization ...
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2answers
1k views

How to correctly install QGIS 2.8.3 with GRASS plugin on Ubuntu 14.04?

I already tried to install QGIS 2.8.3 using the procedure described on: http://www.qgis.org/en/site/forusers/alldownloads.html#debian-ubunt, but grass-plugin do not compare on plugin list! I tried ...
2
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1answer
88 views

GRASS: Landsat 8 GeoTIFF import error

I'm trying to import some Landsat 8 GeoTIFFs into GRASS (in QGIS), and I can't work out why I'm getting this error, or how to fix it. No amount of Googling has been able to tell me anything at all. I ...
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1answer
51 views

r.report giving only per-class cell count

I'm trying to extract the count of each pixel value in a raster, like in this question: How to extract pixel value counts from a raster in QGIS? However, when I run r.report (from QGis (2.10) ...
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1answer
88 views

QGIS + GRASS: r.in.gdal “View output” produces “cellhd file (…) does not exist”

I'm working with a recently installed QGIS (2.10.1) + GRASS (6 v2.0) package, and have been working with some rasters and vectors in QGIS that I'd now like to play with using the GRASS tools. I've ...
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3answers
72 views

Grass GIS: ArcGIS' “Raster to polygon” equivalent

I've got a small clipped extent of a LANDSAT image and I need to have the single pixels as polygons in order to tell the overlap proportions of overlaying polygons. In ArcGIS I used "Raster to ...
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0answers
89 views

Trouble with kernel density estimation

I have been trying to find out how to make the SAGA and GRASS kernel density tools work in QGIS 2.8. I have had a lot of trouble trying to get them to work as they produce useless results seen below. ...
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1answer
78 views

How can I change the way r.cost and r.drain modules work?

Look at the picture #1. This is my cost surface raster that has only 2 values. Area restricted for path to cross (red one) and area that is free to go (yellow one). As I need it and as I undestand how ...
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85 views

Problems using GRASS tools for topology validation in QGIS

I'm working with a shapefile of Enumeration Districts (Setores Censitários) of the 2010 Brazilian Census. Enumeration Districts (ED) are smallest areas for which Brazilian Census data is available. ...
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84 views

How do I use r.horizon in QGIS?

I have a raster file I wish to find the horizon angles from. I am currently using QGIS 2.10.1-pisa (the latest updated version) with the GRASS plugin (6.4.3 and 7.0). I have a raster file generated in ...
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1answer
44 views

Grass gis or Qgis trade area?

I know it's possible to make a trade area (service area) in ArcGIS. But Is it possible to make a trade area with a network data set in Grass GIS or QGIs?
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1answer
58 views

GRASS 7 Cost surface and elevation points development

I'm a new to GIS and I need some help. At the moment, I'm trying to develop an optimal path across an area by using GRASS 7 features. It is very similar to the task given here. The problem is that I ...
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1answer
15 views

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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1answer
200 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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1answer
37 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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19 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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113 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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1answer
52 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 ...
2
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1answer
91 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 ...