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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Can't launch GRASS GIS 6.4.3 GUI on windows 8.1

As title, I downloaded GRASS GIS from this website: GRASS GIS - Home, and I choose winGRASS 6.4.3 standalone installer to download. After I installed, I click on its icon: I can't launch it even ...
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9 views

Why do GRASS' NC dataset and USGS' CONUS dataset coordinates disagree?

In the course of trying to figure out a specific data extraction task, I'm trying to understand the coordinate system used by GRASS. For a while, I'd been working with elevation data near Raleigh, NC, ...
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7 views

How to process a big number of raster outputs?

I am new to python and QGIS. I'm trying to take some simple operations (e.g. count, average) over a big number of raster maps from a python script. I'm using the "r.series" algorithm (from processing) ...
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9 views

GRASS make local relief error

While using/trying to make a local relief in GRASS with the plugin r.local.relief i stumble across a error. ERROR: G_realloc: unable to allocate 15000000 bytes of memory at ...
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170 views

where to perform principal components analysis and tasseled cap transformation [on hold]

I want to perform a principal components analysis (pca) and a tasseled cap transformation (tasscap) for a classification.Should i perform pca and tasscap on the original bands of my image or on the ...
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49 views

Time processing in GRASS?

I am computing NDVI for Landsat TM in grass 6.4.3 in raster map calculator, and time processing is many hours and finally tke message is "failed". trying to find a solution I discovered that it ...
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1answer
76 views

Export of group = multiband raster to another format not works in GRASS

I am really new in GRASS and my question is really basic but I dont realize where I am wrong. I have a set of single layers in my PERMANENT from some Landsat images (1 landsat = 7 one layer ...
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19 views

How to find the path after “cannot find module” message when I try to use grass tools in qgis [on hold]

I use mac and when I try to use grass modules in qgis (brighton) I get a "cannot find module" message.
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192 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: ...
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30 views

Activating GRASS GIS in QGIS

Apparently, my linux ubuntu setup of QGIS doesn't contain grass gis, although when I initially installed it last week I added grass gis to the command line. Anyway, I typed in once again and installed ...
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132 views

GRASS i.landsat.toar returns empty raster

I am trying to use the GRASS module i.landsat.toar. Currently the files created are empty and it spits out: So it seems that it is not picking up something? The location is set to the extent of ...
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130 views

How do I install mdenoise in GRASS?

How do I install mdenoise in GRASS 6.4.3? I've already successfully installed r.denoise, and have downloaded mdenoise from wget http://www.cs.cf.ac.uk/meshfiltering/index_files/Doc/mdsource.zip. How ...
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9 views

GRASS GIS : ScriptError : Unable to fetch interface description for command 'd.rast'

I'm new to GRASS GIS (6.4.3) and I'm trying to use the r.watershed command. I imported the GTOPO30 DEM in tiff format, but I can't display it. I get the following Script Error: "Unable to fetch ...
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4answers
6k views

How to smooth a DEM?

I have a SRTM DEM and I want to create a shaded relief from it. I created the shaded relief in GRASS and the result is very nice, but a little rough becouse the area is near flat and the DEM is 90m in ...
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235 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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25 views

How to merge two rasters when are on the same place

I have two rasters in GRASS GIS. first : raster of DMR, raster picture of relief - created from high values second : raster of buildings where pixels of every building have value of high of this ...
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31 views

I have an error when I execute a command in grass raplat

I use grass 6 in ubundu. I have putted the date into the .csv file and the antennas in .msi format, but when I try to execute the command in terminal "r.radcov" the system show me an error as: Error ...
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16 views

Grass functions (for example, r.li) on QGIS Processing Toolbox

I need to know if it is possible to add other functions, such as r.li to Processing Toolbox. Thanks.
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2answers
501 views

How do I reproject one raster to match another's in GRASS

I have two raster layers, A and B, which have information about the same location but have different projections and datums. How can I reproject layer A to match the projection and datum of layer B? ...
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10 views

Is this error “invalid context…fatal error” due to GRASS GIS bug or the system?

Copy of error message that appears in the terminal (Macbook Pro, OS X 10.9.5): MacBook-Pro.local Python[2653] :CGContextRestoreGState: invalid context 0x0. This is a serious error. This ...
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14 views

Is there any way to add the Origin ID in the isolines calculations (GRASS GIS)?

I would like to ask whether there is anyway in to add the OriginID in the calculations of the Isolines (v.net.iso) in GRASS Gis. The calculations are a bit useless if they only include the cost ...
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13 views

What causes v.net connect “Failed to find intersection segment” and how to fix it?

In GRASS 7, when running v.net connect, I get the ERROR: Failed to find intersection segment and no output is generated. The only mention of this error Google found is in the source of connect.c What ...
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3answers
27 views

How to create custom color ramp using “r.colors” GRASS GIS function?

I am trying to assign a raster/grid a custom color palette in GRASS using the "r.colors" function. r.colors map=Consensus_BRT_RCP85 colors=rules This allows me to input my rules for my color ...
2
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1answer
60 views

Trying to extract arc information from a Suburb shapefile

I downloaded some shapefiles from the Australian Bureau of Statistics (ABS). It's basically showing a bunch of suburbs when I view the shapefile through a GIS tool. The GIS tool that I am using at ...
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48 views

Error in executing commands in GRASS GIS

I'm using Grass 6.4.3RC2. I have a problem because when I execute the command: r.radcov csv_file=cell_list_hataDEM_umts_amc_testTEST.csv dem_map-AlbSRTMdem@PERMANENT clutter_map=AlbClut@PERMANENT ...
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1answer
41 views

How to get mean geographic direction of a polygon in QGIS?

I have a raster height model and would like to calculate the horizontal geographic direction (north, east, etc. - orientation) of each cell, then calculate then the mean value of all these cells in ...
2
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1answer
759 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 ...
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2answers
66 views

Shortest Path Matrix with QGIS/GRASS

I signed up just a minute ago, because I am working on my Master's thesis and could not find a working solution for the following problem: I am analyzing Germany's high voltage electricity grid. I ...
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2answers
54 views

DEM with bathymetric contour lines in GRASS

I am trying to create a DEM from a bathymetric contour lines. Contours are in vector format and the elevation value is negative. To create the surface I have converted the contours in raster (v.to ...
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1answer
43 views

Import BigTiff files in Grass

I am trying to import a raster (geotiff) in Grass with size of 64 GB . It makes me an error like this: ERROR 4: This is a BigTIFF file. BigTIFF is not supported by this version of GDAL and libtiff. ...
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140 views

How to calculate mean aspect in circular statistics?

Measurements of angles (e.g. compass bearings, aspect) are circular in nature (e.g. 0 and 360 degrees coincide) and therefore cannot be meaningfully described by ordinary arithmetic means. I have a ...
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25 views

Is it possible to use d.nviz in QGIS 2.8.2?

I read that this algorithm belongs to GRASS 7 only but GRASS 7 doesn't work in QGIS (Missing dependencies). How do I do that? By the way I want a raster animation with time. And d.nviz can help with, ...
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37 views

Calculate cover loss between years using r.mapcalc

I am working on forest cover raster data for 2 years and am interested in areas with >5% loss in forest cover. I am pretty new in GRASS GIS, so any suggestions for how to create a difference map of ...
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54 views

Sophisticated generation and calculation of Vector entities from Raster Data?

The first image below is shown a raster wish represents the altitude value. I created this raster by applying this process, bu using this process we can manually select an upper and lower area (so 2 ...
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3answers
649 views

Converting Landsat8 DN to TOA reflectance for use in envi

I am used to working in envi, however my current version does not support Landsat8. I downloaded GRASS for the express purpose of converting Landsat8 DN to TOA reflectance for use/analysis in envi. ...
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15 views

Losing polygons when importing shapefile in GRASS

I have a complicated mapinfo .tab file of wildland urban interface zones. They are represented as polygons. I am importing into GRASS using the following command: v.in.ogr -c dsn="C:....path" ...
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26 views

Extracting area from DEM Raster?

After applying constraints to the DEM I polygonised the raster (using GRASS r.to.vect.area) The result is shown below with a lot of vector with resolution = [30 * 30] Is there any solution to make ...
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1answer
27 views

Projection change in QGIS after import & export in Grass

I'm working on an application written with Grass command in python and I have a projection problem. First I create a location with belgian lambert 72 (EPSG:31370) in Grass 7.0. After importing all ...
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1answer
21 views

Duplicated vertices in contour features of GRASS?

I use GRASS to produce contours from DEM (r.contours for SRTM rasters). They looks fine, but most of the line features occures to be duplicated; i.e. verticies duplicated. Here are pictures of output ...
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23 views

Can GRASS compute the line graph representation of an input graph?

I'm interested in computing a line graph for an input graph, preferably in GRASS since I'll be using other GRASS network analysis tools afterwards. I couldn't find any reference to line graphs in the ...
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1answer
54 views

How to have newly added lines split existing lines where they intersect, using QGIS

I have a line shapefile where the lines form a closed polygon. Using QGIS (2.8 on OSX 10.7) I would like to add lines to the layer, basically splitting the polygon into quadrants. Then, I will need ...
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1answer
29 views

Looping inside r.mapcalc in GRASS GIS

I have a Land Cover classification map that I created from 2m resolution multispectral imagery and I am trying to downsample the results to a 20m resolution class map. The climate in question is ...
8
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2answers
263 views

Migrating from ArcGIS to gdal

I would like to collect a table of equivalent or close enough gdal based functions to replace ArcGIS functions (esp in spatial analyst). Are there functions available using gdal to perform the ...
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1answer
44 views

How to create shadows of buildings with r.sunmask?

I need to create image-raster with shadow of relief and shadow of buildings in one. I know how to create shadow of relief but how i can create shadow of buildings with r.sunmask? I dont know how from ...
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2answers
226 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 ...
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36 views

GRASS GIS r.slope.aspect write errors

I am running into an error running r.slope.aspect I have never seen before. When I run it, I get the following output: r.in.gdal complete. Raster map <dem> created. WARNING: map [slope] - ...
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1answer
192 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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41 views

How to use d.* from a python/bash script in GRASS GIS 7.0?

Do d.* commands from GRASS GIS 7.0 run from a python script? I'm trying with this code: import grass.script as grass grass.run_command('d.mon', start="wx3", resolution = '1') ...
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10 views

Move Landsat 7 Image in Grass 7

I got 2 landsat 7 images from the same place but different date of adquisition, image A is well placed, but image B is shifted about 1500 meters east and 14700 meters north. I need to use both images ...
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5answers
992 views

Elevation correction ASTER GDEM2 (+10m)

My ASTER GDEM2 has a average elevation error of -10m for my area. (I testet it using 90 defferential GPS reference points and compared it with old Topo25, SRTM, and GoogleMaps). I would like to ...