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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3
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2answers
667 views

Raster map in different zone () than region ()

I am new to QGIS (just installed QGIS 2.0.1) and am having problems running any spatial analysis tools. I followed the instructions on how to call GRASS tools into QGIS, but when I try to run the r....
1
vote
2answers
79 views

Addon installation problem on GrassGIS

I am facing a problem with GrassGis 7.0.1. I want to install r.viewshed.cva form Addons. I don't get an error during installation but when I try to open the plugin I get the error : ScriptError ...
0
votes
1answer
77 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 ...
7
votes
1answer
1k views

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

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 ...
1
vote
1answer
345 views

Joining table data to features in QGIS?

I am trying to make a map using QGIS but I cannot join table data to features in QGIS. In ArcGIS for Desktop you just open the folder and then join the tabular table with the spatial data table. ...
1
vote
1answer
221 views

QGIS 2.10.1. GRASS Algorithm Processing

While selecting the GRASS algorithms 'Processing algorithm: v.to.points - Create points along input lines' The error message came up: The specified GRASS GIS 7 folder does not contain a valid ...
4
votes
2answers
1k views

Create isochrones from streets with distance values?

I have made isochrone lines using GRASS and QGIS, as shown. The lines show various distances to fire stations on a street network. Now I would like to turn these lines into polygons that look like ...
5
votes
1answer
964 views

Calculate flow path with QGIS

I am trying to replicate my erosion model in ArcGIS for Desktop in QGIS 2.4. I tried to calculate the upstream distance along the flow path for my agricultural field using QGIS. I did the equivalent ...
3
votes
2answers
897 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 ...
0
votes
0answers
452 views

How can I calculate raster cell area for upslope contributing area

I am new to spatial analysis, and trying to follow this tutorial to generate a topographic wetness index for my area of interest: http://gracilis.carleton.ca/CUOSGwiki/index.php/...
2
votes
1answer
105 views

How to brew GRASS with Postgresql support? [closed]

On my Mac, running OS X 10.10.5 and I installed Grass with homebrew: brew tap osgeo/osgeo4mac brew install grass-70 Unfortunately, I cannot choose the pg driver in the db.login menu. Can anyone ...
1
vote
0answers
40 views

For preparing watershed delineation with QGIS Grass module I couldn't find r.watershed module

For preparing watershed delineation here some one has described some steps as follows After step 2, I want to get flow accumulation file, but I can not find this kind of module in GRASS, so I pass ...
1
vote
1answer
720 views

Grass 7 on Ubuntu 14.04. Can't start Grass

I attempted to install GRASS GIS 7 on ubuntu 14.04 using these instructions. When I call grass70 from the command line I get a welcome message and a prompt to continue. I then get two error messages: ...
7
votes
2answers
1k views

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 ...
0
votes
0answers
943 views

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 ...
1
vote
2answers
257 views

How can I extract a smooth river network with QGIS & GRASS?

I´m working with Qgis 2.6.1 and GRASS. I have used the r.watershed module to create a flow accumulation map. With r.mapcalc I have extracted the river network, then i´m using r.thin to thin out to a ...
9
votes
5answers
2k views

Are there any open source tools to detect and fill sinks on a DEM?

Are there any open source or inexpensive tools to detect and fill sinks on a DEM? ArcGIS Spatial Analyst is just out of my price range.
0
votes
0answers
59 views

GRASS: launch <wxpython> GUI fails to launch after selecting mapset

I built grass70 from source on Ubuntu 14.04 desktop using the documentation at the Grass Wiki. I can initialize grass70 from the command line, and the startup GUI appears to select my project / ...
1
vote
0answers
209 views

Use Anaconda's Python distribution within OSGeo4W

I want to use a Python script that executes Grass commands via os.system(). This of course, has to be executed from a running Grass session. However, when I use the OSGeo4W Grass, it does not find all ...
2
votes
1answer
189 views

Is possible to merge landsat 8 with High Resolution Satellite Imagery?

i have landsat8 and High Resolution Imagery (1m) in the same study area, is possible to merge them to get one imagery so that i can take advantage of the accuracy satellite imagery.
0
votes
0answers
40 views

Grass error during script

I've got a serious problem with the following Grass error: r.in.ascii -si input=srsaviLC815173.asc output=srsaviLC815173 --o --q WARNING: closecell: can't move C:\Users\bla\Documents\grassdb/...
1
vote
0answers
27 views

Grass GIS table creation error during r.to.vect

When I execute r.to.vect the following error appears: r.to.vect input=sreviLC815109_-120_-120 output=temp feature=area --o --q DBMI-DBF driver error: ERROR: Unable to create table: create table ...
1
vote
0answers
26 views

Grass GIS r.to.vect: Prevent neighboring cells with equal values from being unified

I've got different satellite image bands as GRASS rasters, which I want to convert to vector dataset. As I want to compare the IDs of the cell polygons later on, the neighboring cells with ...
2
votes
0answers
33 views

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 ...
0
votes
1answer
84 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 "'v....
3
votes
1answer
1k views

Create a 3D surface from xyz csv using GRASS

Apologies if this is a repeat question guys. I am trying to create a 3D bathymetry surface from xyz data. There is approximately 300,000 points with lat, long and z (depth data). The data is sonar ...
1
vote
1answer
132 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 "v....
-1
votes
2answers
41 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 ...
1
vote
1answer
67 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 ...
1
vote
0answers
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 ...
2
votes
1answer
157 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 ...
0
votes
0answers
127 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 ...
1
vote
1answer
70 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 (...
1
vote
0answers
143 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 ...
1
vote
1answer
81 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 test.new.01=...
1
vote
1answer
138 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 ...
1
vote
1answer
64 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 ...
3
votes
1answer
44 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 ...
4
votes
2answers
417 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
1
vote
1answer
118 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 ...
2
votes
2answers
230 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 ...
2
votes
1answer
301 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 ...
1
vote
1answer
54 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' ...
1
vote
1answer
296 views

How to create least-cost path between two polygons with GRASS?

I am completely a beginner in GRASS but I would like to use it to have the cumulative cost of moving between two polygons. More exactly, I would like to get the smallest cost from any point situated ...
0
votes
1answer
64 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
votes
1answer
43 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 ...
1
vote
1answer
70 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 ...
2
votes
0answers
161 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 ...
3
votes
2answers
293 views

Issue while running grass from subprocess

I have a map based web application using geodjango. I needed to display the crime hotspots within a selected polygon area. I found that v.kernel is very good for generating heatmaps/hotspots. So in my ...
2
votes
0answers
56 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). ...