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 can I add r.local.relief to the QGIS Processing Toolbox?

I'm working with QGIS 2.12 and GRASS 7.0.3RC1. I'm making a model using the model builder and trying to add the GRASS addon "r.local.relief" in my QGIS model, but the addon does not show up in the ...
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28 views

Create GRASS Mapset in QGIS 2.12

How do you create a new GRASS mapset in QGIS 2.12? The GRASS panel has only the Open GRASS Tools button.I don't see any way to actually create a GRASS mapset in QGIS.
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32 views

How can I extract flat surfaces from a DEM with GRASS GIS?

How can I use GRASS GIS to get the flat surfaces in this DEM into polygons? The picture is used to show the clearly defined flat surfaces.
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48 views

Converting LandsatMSS DN value to reflectance using GRASS71 [duplicate]

I'm working with a Landsat image MSS by using Grass 7.1,the image's name is LM40080531988146AAA03 with format .tif, the problem is that I want to convert DN value to radiance/reflectance. I'm using ...
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2answers
175 views

Merging contour lines along tile boundaries

I am working with the CANVEC data set. The data in canvec is broken up in to mapsheets. eg. 116B04. I have data covering the entire province of the Yukon. I have merged all the data in to one ...
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47 views

Avoiding edges using GRASS generalization?

I'm trying to process the national wide land cover data into vector polygons. In order to be quick I separate the data into several tiles and process them in parallel. process flow is : 1. v.in.ogr ...
6
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1answer
345 views

Using GRASS algorithms in Sextante under ArcGIS Desktop?

Sextante for ArcGIS comes with SAGA modules. I know that I can use GRASS algorithms in Sextante under gvSIG. But how can I use GRASS algorithms in Sextante under ArcGIS Desktop? I tried to look ...
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3answers
10k views

Viewing .las format LIDAR data in QGIS?

Is there an easy path to visualizing this LIDAR data? I have QGIS, and some USGS LIDAR data in (.las) format downloaded from http://lidar.cr.usgs.gov/ . This means I have both the (.las) and ...
6
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1answer
7k 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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44 views

Wrong area using Albers Equal Area Projection in GRASS for Java, Indonesia

I am just getting to know GRASS 7.0 and I am struggling finding a good projection to work on a spatial analysis of Java, Indonesia. I am new to the forum, so if information's are missing for a better ...
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2answers
71 views

Vector to raster conversion [solved]

I'm using GRASS but, in case, I'm also familiar with R and QGIS. I'm trying to convert a vector area map into a raster one. My problem is that the resolution of the raster is too low (and I can't ...
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2answers
87 views

How to calculate the distance to the nearest water source?

I have a polygon hydro layer of my study area and am trying to calculate the distance to nearest water bodies from my site. Since my site are 2km*2km grids I am not sure how to calculate it? Whether ...
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24 views

A vector object not being replaced in temp folder when using 'for' loop in R

I am currently running GRASS GIS through R interface and got stuck at this point; where I am using a 'for' loop in R, and the code is as follows: for(i in 1:nrow(Snapped_SSP_DSN)) { ...
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2answers
66 views

How can I calculate flow length in QGiS/GRASS?

I have these rasters: DEM Flow Direction Flow Accumulation I would like to calculate the flow distance of every pixel to the outlet of a basin. In Arc-GIS, I can use the flow length. But I don't ...
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109 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 ...
4
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1answer
804 views

Solar irradiation calculation using r.sun

I am trying to compute the global solar irradiation for a region and the run times seem to be a bit too high. I have as inputs a Digital Surface Model with the buildings and a Digital Terrain Model ...
2
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1answer
438 views

How to visualize a 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 pointcloud into qgis from a datafile. Now i'd like to ...
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1answer
78 views

Calculate Volume over sloped ground in GRASS GIS

I am trying to do some volume calculations on a DEM with GRASS GIS. However, I believe r.volume measures everything from 0. The ground underneath the pile I'm measuring is sloped. I would ...
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19 views

GRASS: strange classification output and reject map from “i.maxlik”

I am trying to perform a supervised classification with "i.maxlik". I have three bands: 1) elevation (a dem); 2) reflectance (derived from Landsat ETM+ band4); 3) cumulative solar radiation (derived ...
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1answer
294 views

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

Is it possible to generate a boustrophedon pattern which fill a vector Region with GRASS? I have a vector region in GRASS. And I would like to generate a vector (a polyline) being the bostrophedon ...
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1answer
36 views

Error while executing v.rast.stats command in grass plugin in qgis

I have a vector polygon which I imported in grass. I also have a raster from which I have to extract the value. I ran v.rast.stats command in QGIS 2.12. The command was executed with error. The error ...
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1answer
80 views

What happened to the GRASS Browser in QGIS?

In the past I could display the imported layers in the GRASS toolbox within QGIS. This was possible under the tab "Browser" as you see in the image. Lately I'm missing this tab. The QGIS version is ...
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1answer
29 views

Unable to open shapefile with GRASS GIS? [closed]

Is GRASS GIS able to work with a shapefile (*.shp)? I can´t open my shapefile (328000Kb) in that program. I want to dissolve a shapefile in GRASS because on QGIS the process is very slow.
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54 views

Making GRASS GIS 7 Ubuntu bash file work on Windows 7

I have created this bash file (.sh) while working on watershed analysis stochastic simulation in GRASS GIS 7.0.2RC1, which is running on Ubuntu. It worked perfectly and I received the correct results. ...
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How to set all pixels with value <= 0 to “nodata” in DEM raster?

I have a DEM raster with pixel values between about 3000 and -0.0003. I need to set all pixel with a value of 0 and smaler (<=0) to "nodata" (for later raster calculations and to reduce the ...
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i.spectral tool error

system description: Windows7 32 bıt OS, Grass GIS 7.0.0 Gnuplot 5.0 Solution attempt 01: On the basis of following thread, commented out said path check lines from i.spectral.py script: ...
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1answer
28 views

how to calculate the mean value of pixels of a raster in Grass plugin in qgis?

I am using grass plugin in qgis 2.12. I have to estimate the average value of all the pixels but don't know how to do it.
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1k views

How to resample a raster in QGIS?

I've got a boundary file that I would like to resample the raster file from a 30m grid to a 10m grid inside the boundary file. When I try and do it in Qgis or Grass all I get is one big raster cube ...
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1answer
25 views

Calculating Categorical Raster Areas per Polygon

I've got forest fragmentation data from which I've extracted pixels that correspond to forest edges and patches. I've also got a shapefile of counties in a US state. I'm trying to get the area of ...
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2answers
954 views

Why is this SRTM TIFF not visible in GRASS GIS 6.4.3?

I want to use interpolated SRTM data for Germany to generate an STL terrain map for use in a CFD application. My SRTM data comes from the OpenDEM project. SRTM data normally has voids, but this data ...
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1answer
54 views

Reproducing GRASS GIS network analysis tutorial in QGIS Field Calculator

Im looking to reproduce the assigning of road speeds as denoted in a GRASS GIS tutorial (v.net.alloc tutorial), where the road speed is assigned by road type (i.e. 'interstate' = 75 mph etc.) to then ...
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32 views

QGIS opened as Grass - with no QGIS GUI [closed]

I downloaded QGIS 2.12.1-1 x86 64; but when I opened the installed software under the title QGIS, a Grass interface came up. There is no QGIS GUI with a GIS format (Pan, enlarge, ect)
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20 views

grass r.watershed to larger rivers parallel lines to same stretch

I'm trying create stream channels with r.watershed grass64. However, it shows two or three parallel lines for the same stretch of river. The river is large in some parts, but is just one river. Does ...
4
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1answer
41 views

GRASS 6.4 Reinstallation for Ubuntu

I need to reinstall GRASS 6.4 on this Ubuntu computer due to compatibility issues. I had installed GRASS 6.4 a few weeks ago to work with a simulation program. I used the command apt-get install ...
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2answers
76 views

Grass GIS: Number of CPU cores to use

E.g. in SAGA GIS it is possible to set with one click the number of CPU cores to use during processing. Is this also possible in Grass GIS?
3
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2answers
142 views

Least cost path between various points QGIS

Is there an easy way to find the least cost path (LCP) between various points in an open source GIS? This question has actually already been asked here: How to find a least cost path through several ...
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1answer
165 views

grass gis i.atcorr input should be reflectance or radiance

My question is what should be the input image in i.atcorr for grass 6.4.4 version? I tried giving both reflectance (DN) and radiance as input but values are coming properly. I read some where, it ...
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0answers
34 views

C/C++ function to return minimum set of points required to represent a geometric shape

I am looking for a method from Grass, GEOS, or similar that will delete those points in a geometry which do not affect its shape. Example 1 +----+----+ p0 p1 p2 p1 can be deleted without ...
4
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1answer
44 views

Why can't I see v.net in QGIS GRASS tools

I have noticed answers such as Is there an open source tool to planarize graphs? stating you can use GRASS v.net from within QGIS. However I can't see it - my QGIS processing GRASS toolbox contains ...
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2answers
1k views

How to remove z & m coordinates from kml files

I've recently received some parcel data in shapefile format that has z & m coordinates (all = 0.0). The WKT for a typical parcel looks like this: "MULTIPOLYGON (((2672464.560700002 ...
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Issues related to lack of Landsat 8 Metadata usage in i.landsat.toar run [duplicate]

In my application of i.landsat.toar, I am coming across an issue for which there is previous precedence. LANDSAT 8 i.landsat.toar error GRASS 7 Computer Basics: Data Used: Landsat 8; Operating ...
5
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3answers
600 views

LiDAR data density, returns per square meter

How can I compute a raster showing the number of return points per square meter using SAGA GIS or other open source software? My goal is to obtain a mask which would show me the places (cells) ...
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2answers
707 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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1answer
21 views

What projections and input file parameters are supported by r.resamp.rst?

I always get ERROR: Unable To Seek after I run r.resamp.rst r.resamp.rst input=map30 ew_res=10m ns_res=10m elevation=map10 It actually starts to work but after it finish I get the error and no ...
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397 views

How to create a topologically correct dataset in PostGIS (with GRASS)?

I have shapefiles which I have loaded in postgis and now i am trying to use geometric function in postgis like ST_intersect and they fail because the data is not topological correct. I have tried to ...
5
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3answers
5k 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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28 views

How to determine Grass (i.atcorr) tool control file's “visibility for the aerosol model [km]” value

In Grass, the Atmospheric Correction tool (i.atcorr) reference do not provide information with regards to the parameter "visibility for the aerosol model [km]"stated in the control file.I have ...
2
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1answer
91 views

Atmospheric Correction Model Output for Landsat 8 Image?

Following are my procedure, observation and question/ request: Data Source: Earth Explorer Landsat 8 Grass GIS Version: 7.0.2 RC1 Windows 7 32 bit OS I have been trying to conduct an Atmospheric ...
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1answer
663 views

How to make GRASS and SAGA tools capable to use in QGIS?

I installed QGIS, GRASS and GDAL by OSGeo4w package, and as I finish the installation, I want to use GRASS tool, I face this problem: But I already installed GRASS and SAGA, how to make those tools ...
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3answers
67 views

Storing large number of mapsets with many raster maps

OS X El Capitan, GRASS GIS 7.0.1 I have a location with about 530 read-only mapsets with each about 2600 raster maps (plus PERMANENT and one link to a read-write mapset), overall 11.255.481 raster ...