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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65 views

GRASS GIS r.walk issue

I have been playing around with GRASS GIS to do a simple cost analysis of getting from point A to point B. I have a DEM clipped to the study area, a raster containing the friction costs, as well as ...
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28 views

How to smooth a shaded relief map created with the command r.relief in GRASS 7?

How can I smooth a shaded relief map created with the command r.relief in GRASS 7? I read about the plugin r.denoise but I can only find it for GRASS 6... Thanks in advance. Bryan
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19 views

Is there a max number of cells which r.surf.contour can interpolate in GRASS?

Nothing less, nothing more... I'm wondering if there's a max number of cells which r.surf.contour can interpolate in GRASS, because I have to interpolate a region of 24000 rows x 23000 columns but I ...
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23 views

Reading L1B ASTER in GRASS using r.in.aster

I'm having a problem getting an ASTER L1B to be read in GRASS using r.in.aster. The output the command shows this: (Wed Apr 8 17:49:03 2015) Command finished (1 sec) (Wed Apr 8 17:49:37 2015) ...
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143 views

Grass Processing tools via QGIS : v.clean snap, chdangle, and rmdangle

Using QGIS 2.6 Grass Processing tools, I'm trying to clean up topology on a water network layer. I noticed topological errors when first trying to break all lines on intersections using v.clean break. ...
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2answers
128 views

Is d.mon xN deprecated in GRASS in favor of something in the wxGUI?

I'm trying to learn command-line GRASS (6.4.3) using the KyngChaos binaries on a Mac (10.8.4) from Neteler and Mitasova's book, Open Source GIS: A GRASS GIS Approach (3rd ed.). I've learned from this ...
3
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1answer
38 views

Generate a raster with a uniform value using QGis

I'm working on a project using the qgis-modeler and i want generate a raster with a uniform value. i'm using r.surf.random function of GRASS which need min and max value but i want have only one ...
9
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1answer
663 views

Kriging on GRASS+R - cannot allocate vector of size 146.5 Mb

I'm trying to do a groundwater elevation map with an Ordinary Kriging on R, but always resulting on the lack of memory cannot allocate vector of size 146.5 Mb allocation (windows xp 32bit). ...
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3answers
1k 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 ...
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2answers
88 views

Ls factor, flow accumulation, watershade, relief in Quantum GIS 2.2

I'm a beginner quantum gis. I want to make the LS factor of 30m DEM that I have merge and set the projection in wgs 84/UTM zone 49S (EPSG ; 37249). I'm having a problem when trying to create relief ...
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1answer
59 views

Old question without answer: R.Neighbors with large neighborhoods?

I'm working on the same theme as User 32882, and I'm new here. I have the same problem, and update his question with more details. Old question: "I'm running into problems running the r.neighbors ...
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2answers
155 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 ...
2
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3answers
115 views

Find coordinates of given raster value

I would like to get the coordinates of a raster cell with a given value. I suppose many cells can take the same value, in which case several coordinates should be returned. In my first problem I'm ...
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0answers
126 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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1answer
88 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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0answers
25 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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0answers
18 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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1answer
17 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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3answers
1k views

How to delete rings automatically using QGIS/Grass

I'm cleaning up a (very) messy shapefile in QGIS/Grass. I now have several large polygons with numerous (100s) of small rings. Is there a quick and easy way to remove/ fill all these small rings. ...
3
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1answer
466 views

GRASS GIS 7 in QGIS 2.6.1, Windows 7 64bit - Missing dependency

I am using QGIS Brighton 2.6.1. Today I have installed Grass GIS 7.0.0 RC2 to try its topology functions in QGIS. I have activated the provider, set the paths, but everytime I try to use any Grass ...
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0answers
50 views

3d model to point cloud

Excepting FME, is there a way to convert 3d model to point cloud?
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0answers
72 views

develop rooftop solar radiation potential from 3d buildings model (3dm)

Need to create solar cadastre without having LIDAR data. Have 3d buildings model in .3dm (150 000+ roof surfaces, 500 000+ facade surfaces unmapped, dtm 15x15m) with a lot of multipatch geometry ...
2
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1answer
55 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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2answers
87 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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4answers
1k 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.
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2answers
91 views

Difference between FCELL, DCELL and CELL in GRASS GIS?

Can anyone clarify for me please the options in the "precision" parameter when calculating slope, aspect and curvature in GRASS GIS. What is the difference between FCELL, DCELL and CELL?
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1answer
231 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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0answers
81 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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1answer
94 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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0answers
69 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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1answer
173 views

Empty raster returned after GRASS i.atcorr with Landsat8 data

I've searched at length on previous forums but no solution seems to work for me. I'm trying to run the i.atcorr module on GRASS (version 6.4.3 on a Macbook Pro, Mavericks OSX) with Landsat8 imagery. ...
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0answers
20 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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0answers
52 views

Pansharping Problems with Landsat8

I downloaded Landsat 8 Data from Earthexplorer and used that Workflow: http://courses.neteler.org/processing-landsat8-data-in-grass-gis-7/ Now I want to pansharp the Landsat 8 Datas. For that I used ...
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0answers
31 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
29 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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1answer
165 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
79 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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3answers
3k views

How to rasterize a vector map?

I am looking for a way to create a raster grid from a vector map. I have a map consisting of shapefiles which I want to export as a raster with UTM coordinates. I was thinking of something using the ...
2
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2answers
149 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 ...
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2answers
177 views

QGIS – Raster Calculator: Using flat (no data) areas of an aspect-raster in the raster calculator

I´m playing around with the Raster tools, following more or less the qgis-tutorial but using my own data. When I calculate the aspect of a DEM, flat areas are (logically) left without data. However, ...
57
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6answers
28k views

How to build effective heat-maps?

Using ArcGIS, QuantumGIS, Grass, and/or GVSIG What are some of the tools and processes involved in building effective heat maps? What are the plugins involved? What are the major data requirements? ...
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0answers
56 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. ...
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2answers
49 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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1answer
47 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 ...
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1answer
30 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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0answers
58 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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1answer
51 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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0answers
57 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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36 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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1answer
87 views

r.composite gives blank image output in GRASS GIS

While running r.composite in GRASSGIS GUI command the image formed looks absolutely blank. The data I used is listed here below. IRS-LISS III Multispectral coverages. (i.e. band 2, 3 and 4 for Blue, ...