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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Grass GIS animation tool: zoom in to area of interest

The Grass GIS animation tool is great, but I'm struggling to be able to zoom into an area of the original rasters. Do I have to clip the rasters to achieve this, or can I use the advanced section of ...
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286 views

filling up a depression to create new surface

A collegue here has a problem I cannot help with. She has the surface (as raster) of a landslide release area (from AFTER the slide) and wants to calculate the calculate the theoretical/approximate ...
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5k views

Converting point grid to raster using GRASS?

If I load the original .csv file, I then have a map of the African continent represented by 14069 data points covering it at 40x40km resolution. Each data point shows solar radiation means across the ...
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112 views

GRASS r.in.lidar tool generates incomplete rasters

I have been trying to import a huge LIDAR file (10.5) Gb to GRASS GIS using r.in.lidar. It does the task, but only for part of the image, as shown below: Canopy Height Model (CHM) generated with ...
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19 views

Matching Python and GRASS projection

I have a colleague producing maps with the following Python Basemap projection: from mpl_toolkits.basemap import Basemap m = Basemap(width=6000000,height=3900000, ...
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82 views

Cost Distance Map in QGIS

My question is very similar to Cost Distance Analyst In QGIS? However, I'm looking for a means by which I can create a raster displaying the cumulative cost of each pixel to a specified destination ...
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28 views

Issue running r.region in GRASS command line

I'm currently attempting to use r.region to preform analysis on a specific area of a raster image. I'm receiving Lat/Long data from the step before me, but I'm having issues use that data in ...
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22 views

To display custom data on a Shape file

I have a shape file which is a district map. There are close to 800 districts. There are around 30 funding agencies. There are 4 different health programs. The different funding agencies fund specific ...
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770 views

How to create a time series with a NetCDF raster from Ensembles E-OBS using GDAL, R, GRASS GIS or SAGA GIS

I downloaded a NetCDF file that contains daily precipitation values from 1-1-1950 to 30-6-2013. The raster has 23191 bands. http://eca.knmi.nl/download/ensembles/download.php My goal is to analyze ...
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32 views

Is it possible to start the GRASS GUI from R?

I am using the rgrass7 package in R in order to work with GRASS GIS. After having set the needed enviornment variables, I can now launch a GRASS session from R and and work on my GRASS data using ...
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27 views

What does the max_slope_length option do in GRASS r.watershed?

What does the max_slope_length option do to the r.watershed program in grass? According to the manual, it should limit the length of a stream. Does this mean a max_slope_length equal to the raster ...
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27 views

Problems with QGIS 2.14.1 and GRASS 7.0.3 [duplicate]

I been having problems with modules GRASS / GRASS 7.0.3 in QGIS 2.14.1 I did the installation with Standalone Installer QGIS Version 2.14 (64bit) QGIS-OSGeo4W-2.14.1-1-Setup-x86_64.exe My OS: ...
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61 views

Grass processing not configured in OSGEO4w QGIS 2.14.1

I get the below error when I try to use grass processing from within QGIS. The error is given on all commands and I have got this error on 2 machines. I am using windows. "This algorithm cannot ...
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1answer
250 views

Problem opening GRASS GUI: libgeos-3.3.6.so: cannot open shared object file:

I have been using GRASS to process some Landsat imagery but very recently, and as far as I am aware - after having done nothing different or changing the settings, I am trying to use GRASS and on ...
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22 views

Process road polylines to not overlap building polygons

Is anyone aware of a processing tool in Grass or similar which will find segments of polylines which overlap polygons in another dataset and reroute the polyline to avoid the collision? My problem is ...
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150 views

Why are the holes in my polygons not generalized?

I have one polygon layer with many holes. I would like to generalize it. I used v.generalize of grass. With it, I used chaiken algorithm. But, only the borders of polygons were generalized, the holes ...
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68 views

Convert xyz points to topography and calculate mean slope

I am working on point data (x, y, z) in meters from origin. I have between 24 and 35 points for each plot (10mx10m), with random locations. I would like to modelise topography over the whole plot in ...
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114 views

Atmospheric Correction for multiple Landsat-8 scenes

I need to perform an atmospheric correction for Landsat-8 data and can't find a solution. There is a very limited amount of information dealing with L8-correction methods in a comprehensive way, ...
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1answer
47 views

command r.stream.order not found in grass 7.0.3 how to install r.stream module?

I have installed QGIS 2.14.1 and GrassGIS 7.0.3 I found in OSGEO Grass wiki page a command that calculate Strahler's and Horton's stream order Hack's main streams and Shreeve's stream magnitude from ...
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3answers
3k views

How to calculate LS Factor of Watershed for RUSLE Calculation?

I managed to get subbasins for my catchment (7 km^2) with their areas but I haven't figured out how to get the LS factor (see Revised Universal Soil Loss Equation) from it. I have the vector file ...
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13 views

What does the blocking option do in GRASS r.watershed?

What does the blocking option do to the r.watershed program in grass? According to the manual, it should stop water from being routed past that location, but it appears to have no effect. I'm trying ...
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399 views

Problem importing LiDAR data in GRASS 7

I compiled GRASS 7 on Ubuntu 12.10, with liblas in order to run r.in.lidar and v.in.lidar. I now want to import .las data; the option in file -> import raster data -> LAS LIDAR points import is given ...
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1answer
66 views

How to use GRASS raster tools in the Processing modeler?

In the Graphical Modeler of QGIS, I don't see a way to import a layer into GRASS. The modules "import loaded raster" are not accessible in the Modeler. I want to use GRASS reclassify module, because ...
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460 views

How to interact with GRASS GIS vector map topology “level/layers” from terminal/command line?

Is there anybody out there that can maybe assist in the most simplest form of code to call on command line to "export topology" (which is level 2 information in GRASS) as separate spatial data, as ...
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213 views

Calculate River Runoff Volume (Q) with GRASS

I want to calculate Hydropower between points at a River. I already created a Rivernetwork and the Accumulationmap (without weighting) with r.watershed. My next Step was to set equivalent points along ...
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2answers
287 views

GRASS GIS not starting

I have a problem with GRASS GIS 6.4.3. I installed QGIS 2.4 with GRASS GIS 6.4.3 GUI on Windows 7 64 bit - admin user. When I click on GRASS GIS icon the program not starting (without error ...
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1answer
502 views

QGIS 2.14 GRASS geoalgorithms don't work?

I instaled qgis 2.14 and grass geoalgorithms dont work. Only 160 geoalgorithms and should be 168. MsBox: Missing dependensy, It seems that GRASS is not correctly installed and configured in your ...
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1answer
59 views

Quantile in QGIS python Plugin

QGIS is very powerful when it comes to styling Vector Data. When it comes to Raster data, ArcGIS still has some advantages including Styling based on Quantiles. See my earlier post: For this I want ...
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77 views

Looking for similarity analysis tool between raster and vector layers in QGIS?

I'm aiming to do a similarity analysis between a raster layer and a vector layer. The raster layer is a 5-class ice map and the vector layer (points) contains ice jam events data. The goal here is to ...
3
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61 views

Invalid Geometry, what's wrong with the geometry?

I am using QGIS (2.10) to make a growing zone map of the U.S. from some data I found online. I need to reshape to fit into a U.S. map, and I find it's easier if I break the shape into smaller parts, ...
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513 views

How to create a mosaic in QGIS with cutline and feathering for Landsat-8 imagery

1 - I have two scenes Landsat-8 RGB 6/5/4 and I need to mosaic them: 2- This is my cutline in polygon format that will smooth the overlapping area: 3 - So, I need to create a mosaic with ...
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73 views

Understanding intersection of GDAL and QGIS?

Background I'm starting a project that will be done entirely through Python, except perhaps at the end for visualisation. So far I've been doing it with ArcGIS and arcpy, but we'd like to move it to ...
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36 views

Calculate shortest paths for each output area in catchment through road network to a single point (i.e. store)

The title sums it up pretty much. I'm looking to derive trip distributions to a single store using population data and distance within a prescribed distance catchment. I have calculated the catchment ...
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302 views

Automatically apply topology rule to only selected portions of a .shp file?

I am looking for some examples/tutorials on how to apply a topology rule to only a selected portion of a shp file using a script in ArcGIS/GRASS. Using ArcGIS seems to always require an interactive ...
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60 views

installing grass71 on centos6

I am installing grass71 on centos6 , i have the following message after running grass71 [bachir@nexus ~]$ grass71 Starting GRASS GIS... g.gisenv: /lib64/libc.so.6: version `GLIBC_2.14' not found ...
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30 views

GRASS r.watershed problems in QGIS 2.12

I have a weird error when using r.watershed in QGIS and I have depleted all my ideas. Yesterday it was working normally and generating all the files, then suddenly it stopped working and shows the ...
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3answers
3k views

Is there a way to automate the preprocessing of LANDSAT data?

I'm currently enrolled in a remotesensing course, using LANDSAT data. Part of my course is about standardizing the scenes based on radiance values. I assume that because this is such a tedious task, ...
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31 views

Pygrass reading raster issue

I'm tring to read a raster map from my grassData. I'm using this code import os import grass.script.setup as gsetup from grass.pygrass import raster gisbase = os.environ['GISBASE'] gisdbase = ...
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1answer
60 views

Reshape polygon to boundary of other polygon

I have two polygons. The first one has a white background and brown boundary. To othr has the pink background. how is it possible to reshape to first polygon to the boundary of the other polygon?
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37 views

Will Grass GIS 6s atmospheric correction take raster as input for atmospheric parameters

I am working on atmospheric correction using 6s in Grass 6.4.4 version(i.atcorr module). I want to use raster data set for atmospheric parameters. Presently I am creating an icnd (input ...
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1answer
190 views

How to set QGIS 2.14 on OS X to use GRASS 7

My current QGIS installation (2.14) on OS X 10.11 is set up to work with GRASS 6.4.4. I am guessing this is the default GRASS version that comes preinstalled with the QGIS package maintained by ...
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3answers
223 views

Looking for large GML files containing vector polygon data

I have few vector data files with 500 to 700 MB GML files. But I am looking for files larger than these preferably 1 GB, 2 GB. It would be helpful if somebody can provide some pointers regarding the ...
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1answer
59 views

Pygrass ERROR: Mapset is not set

I am using Pygrass in a a Python Grass GIS stand alone application. I am using GRASS GIS 7.0.3 on a Windows machine and Python 2.7.4. I am initializing a new Grass environment. I can work in this ...
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1answer
115 views

Why can't I enter decimals in QGIS r.water.outlet?

I am using the latest version of QGIS 2.14. I have a raster DEM file. I ran the r.watershed and it created all the raster layers for flow direction, stream, etc. My next step is to run ...
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53 views

Keep “no data” tiles with r.reclass rules

Working in QGIS 2.14.0-Wien. I want to reclassify a raster with the r.reclass GRASS 7 tool, but want to keep the "no data" tiles as "no data". I understand that I need to create a text "rules" file ...
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23 views

GRASS r.sim.water (ERROR: Required parameter <dx> not set)

Running r.sim.water (SIMWE) model: r.sim.water -t --overwrite elevation=elevation.10m@PERMANENT dx=elev2_dx@PERMANENT dy=elev2_dy@PERMANENT depth=depth160308_ niterations=90 output_step=1 fails ...
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22 views

v.overlay in GRASS

As I understand, v.overlay module can be used for polygons overlapping processes. Polygon clipping, union processes can be done. There are many algorithms for these operations. Which algorithm is ...
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41 views

v.net modules QGIS 2.14 OSX

the .net modules have been added to the toolbox for 2.14 but I can't see them running under OSX (10.11.1) using kyngchaos. I can see other Grass 7 tools but not the v.net ones. I know I can run these ...
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2k views

How to interpret GRASS v.kernel results?

GRASS manual reads: v.kernel - Generates a raster density map from vector points data using a moving 2D isotropic Gaussian kernel ... Ok, but how do I interpret the results? I understand that ...
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54 views

Specify target elevation with r.viewshed in QGIS processing toolbox?

How do I specify the target-height in r.viewshed when using the operator through QGIS's processing toolbox? It doesn't seem to be available. Who should I contact to adjust the interface such that the ...