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 to mosaic rasters in grass gis?

I am new user of GRASS GIS. I need to know how can i mosaic different satellite imageries using GRASS GUI? I was trying to use i.image.mosaic, but could not succeed. I have been looking for online ...
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26 views

r.univar - which format for working in GRASS GIS?

As part of a cut and fill-procedure,I want to run the command r.univar, but it returns with no output. I´ve been comparing the properties in the rasterlayer (rasterized vector-layer) with another well ...
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40 views

Change QGIS Processing (Sextante) default arguments for r.out.gdal

Lately I've been using r.grow through the QGIS Processing Toolbox on several rasters which represent the whole world with 500m grid spacing. It takes many minutes to save the output. The reason seems ...
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57 views

Importing raster and vector: GRASS GIS 6.4.4

Almost giving up on this task, and need some support. I´ve been studying GRASS GIS and training with some tutorials with The NC-dataset. What I want is doing the same task as the one called "Surface ...
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30 views

infer the altitude from a DTM & finally provide it to point / evincere la altitudine da un DTM & finalmente fornirla a dei punti

I would like to complete a point vector's table with Z data. I am not able to take Z coordinate from a dtm (downloaded from ...
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189 views

QGIS 2.4 NVIZ Solution

I am going to ask this question better: What happened with NVIZ? I do not know the exact version that nviz stopped working but it seems around version 2 of QGIS. There are two ways to get to nviz in ...
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4answers
279 views

Create a rectangular buffer from point shapefile using QGIS/GRASS/SAGA GIS/R

I have a points shapefile and I want to create a rectangular buffer (22 x 16 km) around each point. My goal is to create a 16x22 km grid where each of the points is the centroid of the grid. Seed the ...
2
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1answer
34 views

How to define measurement units in grass

I need to get the length and area of some landscape features in the US. My data was in lat and long degrees. I created a new location with an UTM projection and read the data into grass. Now if I ...
2
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80 views

Grass python shell can't find my data

I have a problem, the grass 7 python shell can't find my rasters. When I try to use the python shell to set the region I get "region not found". I can set the region in the grass shell (and other ...
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31 views

Error message retrieval in grass.read_command

I am writing a script in python and would like to get the error messages of the function grass.read_command for seeing why it is not working. I found a webpage ...
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2answers
100 views

Calculating quantile values over a stack of images with grass gis. Help needed on r.series

I need to calculate the values for the 25%, 50%, 75% and 90% quantile over a series of rasters (time series of ndvi values from landsat). I am exploring the r.series command in Grass GIS, but the ...
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1answer
23 views

Grass, Route Finding with Elevation Limits

I've got GRASS (7.0) installed and I "play" with it on ocassion since I am far from a GIS pro. What I want to do is to find all road routes from a certain point limited by distance (path length, not ...
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2answers
129 views

Remote geoprocessing solutions?

I have a relatively old laptop (i5 8Gb) but it is fine for most of my GIS needs. Infrequently I would like to run processes which requires larger amounts of RAM (16G+) but I cannot justify forking out ...
2
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1answer
88 views

r.recode rules file issue

I have a raster that I want to reclassify and I'm using GRASS r.recode from within QGIS v.2.4.0. The rules file I am using has this content: 0:149:1 150:229:2 230:379:3 380:459:4 460:*:5 The raster ...
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95 views

Problem with Bash loop in GRASS GIS

I'm new to GRASS GIS and programming and I'm running into a lot of what I imagine are beginners problems and something similar to this has been asked before, but not In a way that I understand. I'm ...
3
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1answer
133 views

Practical tools to delineate large scale watershed?

I would like to do some watershed delineation at national/regional level (using SRTM-90 data). I have experimented with r.watershed (GRASS 6.4.3) but it fell over when I tried to do big stuff. I ...
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2answers
114 views

Tasseled Cap Transformation on MODIS in GRASS

I would like to know how to perform a Tasseled Cap Transformation on MODIS, in GRASS. I've found this https://searchcode.com/codesearch/view/19063909/ but I don't know if this has been tested. I'm ...
2
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1answer
74 views

How to use grass.script in MacOS

I have installed Python and Grass6.4 using Macports. When I tried to use "import grass.script" in python environment, it gives "no module found" error. I'd spend much time to fixed it but could not ...
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20 views

GRASS GIS 6.5SVN : r.watershed failed to display basin and accumulation maps

I am passing DEM and threshold values as inputs.I want to get basin and accumulation as outputs.I tried it in Grass,process was completed.while dispalying result it is showing white screen (both ...
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49 views

How can I load JSON into GRASS?

I have received rainfall data in JSON format. I want to load the data into GRASS. Sample JSON output: ...
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2answers
188 views

How to fix unreachable nodes in QGIS GRASS network?

I have created a network with the GRASS module v.net. But when I try to create the travelling salesman path with v.net.salesman, I get: Destination node 9383 is unreachable from node 9398 If I ...
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39 views

Cell file resolution differs from current region in GRASS GIS

Error r.terraflow elevation=cdnh43e_v1@user1 filled=cdnhfill direction=cdnhdir swatershed=cdnhsink accumulation=cdnhacc tci=cdnhtci ERROR: cell file cdnh43e_v1 resolution differs from current ...
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2answers
101 views

GRASS GIS: auto-completion fails in commande line

I'm running GRASS GIS 6.4.3. on Win 7, SP1, 64 bit. The path to my grass-DB is: D:\grassdb Within the GRASS GIS Commande Line, if I press the tab-key to auto-complete only folders, files and ...
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3answers
448 views

Cutting out depth information in raster. Calculating volume in Qgis

I am trying to calculate habitat volume for around 30 fish stocks in Qgis. I have habitat areas (shape files) and Bathymetric information (.tif file). I believe I can calculate the entire volume of ...
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68 views

using r.volume model GRASS plugin in QGIS

I am calculating volume of bathymetric data in the form of a clipped raster in GRASS with a Custom Lambert projection centered around 70degrees North, using the module r.volume in GRASS. Side note: ...
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2answers
102 views

GRASS GIS not starting

Hello my name is Luca and I write from Italy. I have a problem with GRASS GIS 6.4.3. Last week I installed QGIS 2.4 with GRASS GIS 6.4.3 GUI on Windows 7 64 bit - admin user. When I click on GRASS ...
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1answer
119 views

ArcGIS Desktop equivalent to GRASS r.geomorphon algorithm?

I would like to know if in ArcGIS Desktop 10 there is some tool/algorithm which can be used to perform the same analysis that r.geomorphon does in GRASS 7.
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49 views

QGIS OD matrix assignment on network

Using QGIS, I would realize an assignment of an OD matrix on a network, like this one on Transcad. I have: - network - points of Origin and Destiny - flows of traffic for each OD I found a solution ...
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1answer
256 views

Loading GRASS gives error installing QGIS Chugiak on Windows 8.1?

I am experiencing a problem installing QGIS 2.4 Chugiak on Windows 8.1, resulting in a error loading Grass. This may be a problem only affecting certain installations, I'm not sure. I am a noob on ...
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2answers
295 views

How can I import tif file in GRASS GIS

While importing TIFF image to GRASS GIS, I get an error: Location PROJ_INFO is: name: Lambert Conformal Conic proj: lcc datum: nad83 a: 6378137.0 es: 0.006694380022900787 lat_1: 36.16666666666666 ...
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2answers
529 views

How to create GRASS scripts in C# in Windows

Most of the tutorials that I have seen are under Python and Linux. Is it Possible to create GRASS scripts in C# or atleast in Windows. I can create scripts using a different language as a compromise ...
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20 views

GRASS GIS and Liss4MX

i am working on grass gis. how to use grass gis for liss4 of IRS-P6.I have to do atmospheric correction for hilly terrain data.i would like to use grass's i.atcorr. may i know the dependencies and how ...
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28 views

How can I implement GRASS GIS flow direction process from DOS scripting

When I try to implement its showing it work completely in its command prompt(grass) and creating output files also but when I try to view the result its not showing anything in Map Display I ...
3
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1answer
213 views

How to properly open an ASTER data?

Yesterday i downloaded an Aster L1B image from USGS's website. If i load it in QGIS, it doesn't get displayed properly(location wise). Even after i've enabled "On the fly" option, it's not reading the ...
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1answer
50 views

trying to calculate volume using r.volume GRASS - error message

I am trying to calculate volume using GRASS plugin in Qgis using module r.volume however the attached error message keeps appearing. Any ideas?
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1answer
85 views

Error importing raster into GRASS plugin in QGIS

I am trying to import a tiff raster file into GRASS however every time I do this the below error message comes up. I am using a custom CRS so I have tried changing it back to the default CRS but still ...
4
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2answers
4k views

How to generate a DEM from a contour Shapefile?

I want to create a DEM from depth contours (shapefile) in QGIS. I've been trying to work out how to do this based on this previous question, notably from this link from that page, however I'm stuck, ...
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213 views

How to merge overlapping and duplicate lines from vector layer to one single line?

I used the "polygone to line" tool from QGis, to get a line-layer from this polygon-layer: unfortunatly this causes overlapping and duplicate lines, after I broke the qgis-export via GRASS into ...
2
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1answer
66 views

How to convert tif to dep extension?

In white box when i try to import or do any processes it's asking .dep extension How can i convert .tif into .dep extension?? If try to pass LISS3 data in GRASS GIS it is taking as single bands. So i ...
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1answer
50 views

Setting resolution for GRASS raster

I am trying to calculate volume using the GRASSplugin. I have my area information in vector format and my depth information in raster. I read that it is important to set the raster resolution before ...
3
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1answer
86 views

Merge different Landsat scenes in Grass GIS

I am new to Grass GIS, and I really need some help in solving this issue. I have 17 scenes from Landsat8 covering an area. I have created color infrared images of bands 5,4,3 and now I want to merge ...
3
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3answers
313 views

GRASS v.generalize method=douglas not working as expected

I'm frustrated with v.generalize trying to simplify polygons. Those polygons stem from ArcGIS's raster to vector function (imported into GRASS from Shapefile), so they are pretty zigzag like this: ...
4
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3answers
292 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) ...
2
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0answers
198 views

Problem loading output layer QGIS

Every time I run operations with temporary file output from the graphical modeler, I get the following error message: Oooops! The following output layers could not be open CLIP: ...
2
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1answer
59 views

My RapidEye image won't appear in GRASS GIS

I have several RapidEye images that I want to use for object segmentation in GRASS GIS. When I import the the bands they all look like this and the same goes with a RGB composite: I've used these ...
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1answer
640 views

How to extract drainage line network from GRASS GIS and QGIS [closed]

Giving DEM as input is there any way to get drainage network? I am newbie to GRASS and QGIS ,provide any working examples in GRASS GIS and QGIS with procedure.
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37 views

Create “grid” of polygons with the same 3D area based on an underlying raster variable (e.g. DTM height)

This could apply to point or raster values but imagine a raster of a continuous variable such as height (DTM). Is there a way to create a complete coverage of polygons that will have an equal area, ...
2
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2answers
480 views

How to create isochrones from streets with distance values?

I have made isochrone lines using GRASS and QGIS, as shown. The lines show various distances to fire stations on a street network. Now I would like to turn these lines into polygons that look like ...
3
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3answers
194 views

Can a shapefile, or other file, be made from Excel without coordinates

I have two Excel spreadsheets I'd like to make into shapefiles, or some equivalent. I have access to ArcGIS at work and want to try using GRASS as well. I have seen the help on doing so, but only if I ...
3
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2answers
186 views

Resolution difficulties in Grass

I have gone through similar questions to mine here, but I didn't find a solution. Please help! When cropping a raster image by using g.region & r.mapcalc, I get a new image but the resulting ...