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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252 views

Conditional calculation - QGIS Raster Calculator or GRASS r.mapcalculator

Is it possible in QGIS either directly or via plugins to do a raster calculation including an if statement? e.g., if raster1 > 0.3, then raster 1 * raster 2, else raster1 x raster3...something like ...
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73 views

wps-grass-bridge misses essential GRASS tool

I set up a Web Processing Service with 52°North and GRASS (using the wps-grass-bridge). I get a similar result like in the online example here: 52°North WPS Demo I assume it would be similar with ...
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28 views

QGIS WPS plugin misses one parameter

I set up a Web Processing Service with 52°North and GRASS (using the wps-grass-bridge). All went smooth and I get a proper DescribeProcess for i.cluster. As you can see, I need to give the parameter "...
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228 views

Pansharpening Landsat 8 tiles in Grass 7

I am trying to get some nice looking RGB images for visualization purposes, mainly using as background maps, from the Landsat 8 archive. I was following the tutorial provided by Markus Neteler at ...
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3answers
33 views

Unexpected result converting a vector to a raster in GRASS 7.0.0

My purpose is to create a DEM raster in GRASS 7.0.0 starting from a shapefile containing contour lines. The attributes table has a field named QUOTE_INT containing the elevation as integer. I ...
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2answers
740 views

Extract Elevation of Points from DEM using Python QGIS or GRASS

I am utterly new to GIS, so please bear with me if I am providing incomplete information here. I have a DEM file (.dt2). What I am looking to do is as follows: take a series of points specified as ...
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1answer
22 views

Where to get GRASS module r3.out.vtk?

I'm looking for the GRASS module r3.out.vtk. It's featured on the GRASS GIS manual : http://grass.osgeo.org/grass64/manuals/r3.out.vtk.html But it's nowhere to be found, and neither are r.out.vtk and ...
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93 views

3d model to point cloud

Excepting FME, is there a way to convert 3d model to point cloud?
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1answer
145 views

View feature space for multi-band files

I am trying to plot a feature space (scatter plot) for some SPOT images in QGIS 2.8.1. I know a histogram is available in the file properties, but I want to plot eg. Band 1 vs Band 2 to see the ...
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1answer
799 views

How to fix the grass7 package available from the ubuntugis-unstable PPA?

Out of the blue, grass stopped functioning this morning on one of the Ubuntu 14.04 systems I use: $ grass Starting GRASS GIS... python: can't open file '/usr/lib/grass70/gui/wxpython/gis_set.py': [...
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123 views

QGIS, GRASS and WINDOWS 8

Good morning, I'm using QGIS 2.8.1 (Wien) on Windows 8 x64 bit. When I'm trying to lunch the GRASS plugin (6.4.3), Windows shows me the error g.mapset.exe has stop working, then after some times, ...
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169 views

Removing salt and pepper effect

In a land cover raster (categorical map) that is a product of classified satellite image, what is the best way to remove "salt and pepper" effect from the image after classification. I am not ...
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26 views

Using r.neighbors on borders

I have a raster file with pixel size 30 x 30. At the upper border there is half row with "no data" pixels. I want to use the mode function to replace them. I have only thought r.neighbors (from grass) ...
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57 views

Is it right to remove salt & pepper effect from a product produced by clean images?

I have two images from classification (different years) and I want to find the changes of land cover . I have cleaned the two images (salt and pepper). When I create a cross product of the category ...
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0answers
46 views

GRASS_INFO_ERROR(16605,1) while running a GRASS tool

I have a fresh install of QGIS 2.8.1 with the GRASS plugin on Ubuntu 14.04. I opened the mapset I've created in QGIS 2.6.1 on Windows 7. Then I tried to run v.in.ascii Grass tool and I got following ...
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0answers
152 views

QGIS-GRASS firespread simulation module [closed]

I'm trying to do some fire spread simulations in QGIS with GRASS fire spreading simulation module. QGIS ('Processing Toolbox' > 'Geoalgorithms' > 'Misc' > 'Fire spreading simulation') GUI. Already ...
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0answers
596 views

QGIS 2.8 problem accessing GRASS commands [duplicate]

QGIS 2.8.1 Win7 64 bit installed with osgeo4w-setup. I’m trying to run GRASS commands on a LIDAR raster layer but I get the following message: Missing dependency.... GRASS not installed in your ...
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1answer
240 views

G_realloc: unable to allocate 46320000 bytes of memory while managing large .xyz through v.in.ascii

I tried to convert large (~180MB) .xyz file into vector through v.in.ascii in QGIS Brighton (2.6.0) Grass plugin (it should be Grass version 6.4.3). The "primitive registration" stage lasted very long ...
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2answers
279 views

How calculate pixel by pixel the mode (statistic) of multiple rasters (geotiff)?

I have 12 land cover maps, and I would like to calculate the mode to each pixel of the 12 maps (they have the same resolution and dimension). I mean, the final map would be the mode for each pixel of ...
3
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2answers
155 views

Loading Grass 7.0 vectors in QGIS broken?

Running QGis 2.8.1 in Win7 (64bits), installed through OSGEO4W. When trying to load a Grass 7.0 vector file in QGis, the program will simply crash without any notice. I can load old Grass vectors ...
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1answer
294 views

Running Grass7 in conda environment?

I have Anaconda Python Distribution (Python 3.4.3 :: Anaconda 2.1.0 (64-bit)) installed on Ubuntu 14.04. I would like to create a conda environment for running Grass 7. To do that I used: conda ...
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2answers
372 views

Trouble importing NumPy in GRASS. Architecture

I can't get GRASS to work on my system, and after doing some digging I think it is related to me using 64-bit python. I'm not really sure. I get this message... This module requires the ...
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2answers
58 views

Shell/GRASS: Exit loop upon raster value

I am running a loop from a shell script in GRASS GIS 7. Basically, values are subtracted from a raster in each step. I want the script to stop/exit if any of the raster values is 0 or less. Is there a ...
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114 views

Splitting lines at a specified distance and add attribute

I have used QChainage to create points along a line every meter. What I am ultimately looking for, is to split the line layer along this point into segments with the chainage distance as an attribute. ...
2
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1answer
703 views

Visualizing a LiDAR 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 point cloud into QGIS from a datafile. Now I'd like to ...
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1answer
31 views

GRASS 7.0.0beta3 / statistics change after TIF import?

I'm new to this forum, and pretty much a beginner with GRASS (7.0.0beta3 installed atm). So my question is the following: Statistics (mean, min, max) change quite a lot after importing a .TIF grid ...
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1answer
73 views

GRASS Gis v 6.4.4. KeyError: 'version' when start

When I try to start the GRASS it gives me the following error GRASS 6.4.4 (Hellas):~ > ERROR: MAPSET Hellas - permission denied Traceback (most recent call last): File "/opt/grass64/etc/wxpython/...
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1answer
81 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
112 views

How to import and layer stack seperate ndvi bands to grass gis?

I have 20 separate single band NDVI files. I have to import this into GRASS and stack them into a single 20 band image. How can I do that?
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68 views

How to load “soil types” in QGis?

I want to show soil transmissivity per pixel. Thus, I determine water holding capacity of each pixel (ignored other effective parameters). Respectively, I wonder, What is the soil data format and How ...
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3answers
2k views

Error when creating a new mapset with GRASS in QGIS

When I try to create a New Mapset with the GRASS plugin in QGIS I get an error or the program crashes. QGIS 2.6.1 (32-bit install, Win7). QGIS crashes completely when clicking "Finish" in the New ...
4
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1answer
378 views

How to calculate “water accumulated in each cell” using QGis?

I create channel network and catchment area from a DEM with SAGA GIS. I know that flow is starting from a cell to an other cell. Firstly, a cell is filled with water and then it is starting to flow ...
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83 views

Hydropower Calculation

I have assigned the elevation and the volume flow to each point at a river (with v.to.db and v.what.rast). Now I want to calculate the Elevation difference between each pair of points and then ...
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1answer
231 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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1answer
46 views

How can I fill the category field in a raster using GRASS

I have a tiff file with land use data. The land use class in in the value field, but the label field is empty. Now I want to find out which is the area covered by each land use class, but GRASS does ...
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0answers
119 views

setting null values to 0 Landsat 8 Grass 7.1

I am working with Landsat8 images and need to run the albedo function in Grass 7.1.svn. In order to do this, I need to set the null values to 0 to eliminate the black border around the images. This ...
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44 views

automatic extraction of dtm using grass gis

i have generated dsm using erdas lps tool which is in img format. i want to import this file in grass gis and extract dtm. can you please tell me how to input the data , in which format it should be, ...
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58 views

What is the background processing of rainfall thresholding?

I want to create a flood map using Quantum GIS. First of all I create catchment area (flow accumulation). Then, I delineate a Channel Network by applying a threshold to flow accumulation. So I want to ...
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1answer
207 views

tutorial for deriving solar insolation estimates from high resolution Digital surface model

I want to estimate solar insolation using grass gis. I have a high resolution DSM generated from Large Format Digital camera.Being a novice in this field i Would like to have a tutorial and steps to ...
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40 views

How to visualize insolation rasters over color orthophoto in grass

I have generated insolation time raster map using DSM, slope, aspect for day 100 and time 10.95 hrs using r.sun module in grass. The output insolation raster map (color table) i want to overlay on ...
2
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1answer
74 views

Looping for importing and interpolating a lot of LIDAR files?

I'm quite new to Grass Gis and I'm trying to make DEM (digital elevation model) for modelling flooding. I have 170 *.xyz files, which need to be scanned for extents (r.in.xyz -s input=...\filename.xyz ...
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1answer
156 views

How to change the Map Units in Grass?

because v.segment measures all offsets in map units, i have to change it. (I want to put all of 50 meters a point) So I checked g.proj -p: -PROJ_UNITS------------------------------------------------ ...
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0answers
50 views

problem with running raster calculator in grassgis

When I was trying to do NDVI with grassGIS I faced a problem. I cannot run the raster calculation. When I looked to the command console I see that (Sat Feb 21 12:41:58 2015) r.mapcalc ddes = ( ...
2
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1answer
395 views

GRASS 7.1 (dev.) i.landsat.toar error

I am working with Landsat 8 image acquired in 2014. I am trying to convert the raw image (DN) to Top Of Atmosphere Reflectance/Radiance (i.landsat.toar) in Grass 7.1 (still under development). The ...
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1answer
104 views

How to change GRASS language within QGIS?

I use GRASS plugin inside QGIS on Japanese version of windows 7 x64. As I start GRASS tools, all the content show in English but when I try to execute a tool, tools option dispalys in Japanese ...
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2answers
239 views

Export GRASS raster as GeoTiff : nodata values exported as -nan (what happens in R?)

I am using the package raster to work with GeoTiff raster files which I expoerted from GRASS using r.out.gdal. GRASS assigned the value -nan to some raster files (type FLOAT32) for missing values. ...
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1answer
248 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 rasters)....
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1answer
77 views

Overlaying of raster in GRASS for visualization?

I have generated insolation time rasters map in grass using r.sun module. How to overlay insolation time rasters over DSM depicting the color table for visualization?
2
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1answer
2k views

Can QGIS or GRASS convert layer files to shapefiles?

Should I be downloading QGIS or GRASS? I want the program with the most features. Most importantly, I have a lot of .lyr files. Can either of these softwares convert to shp and if so, how can I do ...
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77 views

GRASS GIS: Network analysis doesn't work correctly

I got a problem with the Network Analysis function v.net.iso in GRASS. I tried it so many times but the function doesn't work correctly. I tried to calculate isolines via the function v.net.iso, based ...