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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Merging contour lines along tile boundaries

I am working with the CANVEC data set. The data in canvec is broken up in to mapsheets. eg. 116B04. I have data covering the entire province of the Yukon. I have merged all the data in to one ...
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121 views

How to install GRASS in QGIS Dufour?

How do I install GRASS to run in QGIS 2.0.1? GRASS is not listed in the Plugin Manager and attempting to access it via the Processing Toolbox gives me the following error:
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31 views

Raster Interpolation of Different DEMs in GRASS

I am trying to generate a DEM for surface runoff modeling in GRASS. I have a DEM for the entire watershed at 1ft resolution and another for the small area within that watershed (a parking lot) I am ...
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1answer
169 views

How to pansharpen radiance/reflectance Landsat 8 in GRASS 7?

first at all, I have to say that I'm new GRASS user. I would like to make a pansharp in GRASS 7 with reflectance Landsat 8 bands. I have revised some related posts and blogs, and I didn't find out if ...
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99 views

Trouble with opening/using i.atcorr in GRASS

I'm relatively new to GRASS. I'm running version 6.4.3 on a Windows 7 machine. I'm trying to process Landsat 5 imagery from multiple states, so I was hoping to approximately follow the workflow here: ...
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58 views

Problem with r.drain in Dufour and 2.1

I am trying to perform to define the shortest route between two points using r. walk, r.cost and r. drain. I have successfully done it using grass under Lisboa standallone living in win7. When I try ...
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71 views

GRASS i.atcorr outputs unusual values

I have problems using the atmospheric correction module i.atcorr in GRASS 6.4.3RC3. I try to correct two Landsat ETM+ scenes, but the output for bands 4 and 7 has values that seem to be incorrect. ...
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77 views

Grass installation - MSVCR71.dll error while .Net installed

I have .Net 4.5.1 installed and resently installed GRASS 6.4.3. When I try to start the software I get the MSVCR71.dll error. The only solution suggested in the guide is to install the .Net ...
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1answer
434 views

Import GRASS and SAGA modules to python script

I'm new at this. I am "building" a python plugin for qgis and I want to import modules from GRASS and SAGA but I don't understand how to do it. The plugin I want to import is Kriging interpolation ...
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1answer
142 views

How to define correctly the Grass region in Qgis

I know that my question could be pretty basic for some of you. I am trying to learn GRASS. I have some raster layers and a vector file in EPSG 32614. Using the grass plugin I defined a new map set, ...
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1answer
223 views

r.basin.py GRASS addon

I have added this add on with g.extension on my grass 6.4.3RC3. But it doesnt work... this is the error I can see: Traceback (most recent call last): File "C:\Program Files (x86)\GRASS GIS ...
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1answer
130 views

How to join USDA SSURGO soil table data to features in QGIS?

I am trying to make a soil map using QGIS. The only problem is that I cannot join table data to features in QGIS. In ArcGIS for Desktop you just open the folder and then join the tabular table ...
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1answer
82 views

Set Grass Region in Python grass.script

How can I set the Grass Region in Python without already having a map in the Mapset? Basically I am looking for the equivalent to this window Currently I am only able to extent an existing region, ...
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53 views

Error north coordinate not allowed using r.water.outlet in GRASS

When I am trying to delineate a basin from this code: r.water.outlet drainage=drainage1 basin=basin1 \ east=518675.070417019 north=911542.292643082 Coordinate system: UTM-cartesian xy (used by ...
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1answer
266 views

qgis plugin: “WindowsError: [Error 6] The handle is invalid”

OS: Windows 7 64bit GIS: QGIS 1.8 (qgis.org/downloads/QGIS-OSGeo4W-1.8.0-2-Setup.exe) path variable: GISBASE=C:\Program Files (x86)\Quantum GIS Lisboa\apps\grass\grass-6.4.3RC2 ...
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3answers
173 views

SRTM NASA hillshade grainy appearance

I'm trying to create a hillshade surface from SRTM files downloaded form Earth Explorer, but the appearance is not the expected. It has a grainy surface that I would like eliminate to have a ...
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1answer
139 views

What are the advantages and disadvantages importing vs linking data in GRASS?

I'm fairly new to GRASS, and only recently discovered the r.external and v.external functions. I'm used to working with R and QGIS where all the data is "external". Typically I keep vector data in ...
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1answer
50 views

Re-sizing Raster file pixels

I have 2 JP2 aerial imagery files that are incorrectly sized. They are 100x larger than the other aerial images but correctly geo-referenced (starting x, y co-ordinates). I believe the issue is their ...
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81 views

Touch up tool for rasters?

I was wondering if it were at all possible to manipulate/massage rasters (eg Geotiff) using Qgis plugins or Grass?? By manipulate, I mean manually smooth off interpolation artefacts, blended surface ...
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2answers
485 views

install GRASS Addon in with QGIS

Win 7 QGIS 2.0 GRASS 6.4.3 Hi everybody, I want to install some GRASS-Addons to use them in QGIS. Therefore I run GRASS-Plugin in QGIS an open the GRASS-Shell type: g.extension GRASS opens then i ...
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56 views

how to work with netcdf data in Qgis 2?

Once it is displayed as a raster, how to see data of different time steps? eg. meteorology datamonthly mean and the likes... where to change the time step? how to calculate seasonal average, annual ...
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1answer
505 views

How to get custom colormap onto 3D NVIZ in QGIS GRASS

I am trying to create a 3D version of my 2D raster using QGIS GRASS NVIZ. I have been following these steps: ...
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2answers
279 views

How to remove z & m coordinates from shapes with QGIS? (Or arcgis, grass, gdal, Python…)

I've recently received some parcel data in shapefile format that has z & m coordinates (all = 0.0). The WKT for a typical parcel looks like this: "MULTIPOLYGON (((2672464.560700002 ...
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1answer
89 views

QGIS Grass Plugin fails with r.cost.vect

I tried the following in QGIS with the Grass Plugin: r.cost input=preCostSurface@albi start_points=OSMroads@albi output=cost0109 max_cost=0 And I get the following error: Dev note: Adapted sites ...
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4answers
688 views

How to do kernel density estimation with a physical barrier/ boundary in QGIS?

Does anyone know of a programme that will allow kernelling that takes a boundary into account in its calculation rather than simply masking areas that are impossible? So far I have found: GME add on ...
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184 views

how to make decent sense from scattered river depth measurements

I sampled river depth at scattered positions and I want to be able to make a map and GIS layers out of it. My problems are: As the river meanders the interpolation I do in scientific packages i,e. ...
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28 views

how to interpolate river bathymetry/heights in qgis/grass [duplicate]

Hi all and thanks for your help. I have a csv file containing a set of x,y,z points for river bottom depths. When trying to interpolate the data in scientific computing software (ie, matlab) I have a ...
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39 views

grass plugin in QGIS all of sudden not working as expected

The previous week I was able to use the grass scripts in the QGIS 2.0.1 Dufour toolbox, but today they do not seem to be working. I am not sure where to place a '-c' which was a solution to the same ...
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0answers
146 views

How can I create random concave polygons for test purposes?

In the context of generating random test data using QGIS (in a shapefile): I can generate random, continuous (adjacent) polygons by first creating n random points using ftools and then generating a ...
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2answers
115 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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5answers
966 views

How to generalize and vectorize a LandUseClassification raster file?

I want to vectorize that rasterfile with its 6 landuse classes. The classification is very noisy and have to be generalized before. The result should be a polygone vector file. I use SAGA, (GRASS) ...
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2answers
2k views

How to install add-ons in GRASS?

How do I install the r.inund.fluv script in GRASS? https://svn.osgeo.org/grass/grass-addons/grass6/raster/r.inund.fluv/
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2answers
105 views

Getting started with 'shell scripting loops' in GRASS

I'd like to work through the MODIS-Aqua example here. But typically the hardest bit is getting off the ground. What specifically does it mean by 'shell scripting'? is it referring to the command ...
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1answer
114 views

How to compare accuracy of two DEM using GRASS

How do I compare accuracy of two DEM data (lidar and srtm) (possibly through rmse) using GRASS GIS? thanks
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3answers
963 views

How to pansharpen LANDSAT 8 in GRASS?

Having used QGIS for quite some time for mapping, I was 'forced' to dig into GRASS as pansharpening is not directly executable in QGIS. After understanding more or less the structure, I did some ...
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0answers
50 views

Delete polygon underlap?

I am editing a layer in QGIS with severe polygon overlaps. Is there a way to delete the underlapping portions (i.e. the invisible parts) using QGIS? If I import the layer into GRASS using the ...
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1answer
392 views

Is there a Focal Statistics (spatial analyst) tool in ArcGIS equivalent in QGIS?

I'm attempting to use QGIS v2.0.1 to accomplish the same tasks that I can do using ArcMap v10.1 and I'm running into some trouble finding equivalent tools. In ArcMap I am using the Focal Statistics ...
3
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1answer
146 views

GRASS 6.5 or 7.0 - Need Help with Loop Script

I am new to Python and scripting in general. This is also my first time a posting question. My overall goal is to create a script that I can cycle through all the raster maps in a mapset and then ...
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20 views

Unicode Characters in GRASS ps.map instructions file

I am trying to put text on a ps.map generated map and the text contains the degrees symbol. I can insert the symbol into the instructions file, and it looks fine, but when I generate the map, the ...
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22 views

accuracy of classification in qgis [duplicate]

I have my classified map and my validation points. I performed point sampling with validation points to my classified map. but i am fuzzy with my next step. Some help?
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148 views

Problems with SEXTANTE

maybe the answer is somewhere, but i can't find it right now... I'm getting problems with SEXTANTE and algorithms with GRASS, SAGA... Always is the same, they can't open the files, the error is the ...
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1answer
102 views

How to duplicate this QGIS workflow with gdal/GRASS? (reproject and crop a raster)?

I have a number of rasters (rgb images) that I want to re-project and crop. I have established a workflow for doing this in QGIS, but I'd like to do it using gdal modules, because the output is being ...
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0answers
27 views

suggestions for open source GIS in monitoring [duplicate]

my name is weng and i am currently conducting my research Entitled "Architecture for GIS based monitoring system for malnutrition" and one of the requirement would be to identify what open source GIS ...
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1answer
119 views

Grass GIS and Python Error

I am trying to use Python with Grass GIS. To get started I try to read in a raster TIFF. The import of grass.script works fine: import grass.script as g But if I am trying to run a command I get ...
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4answers
630 views

GRASS 6.4.3 Crashes on Startup; libintl-8.dll cited

I recently installed QGIS 2. I used the advanced OSGeo4W installer that I downloaded from the QGIS download page. GRASS is included in the stack. When I attempt to open GRASS, I receive the following ...
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2answers
245 views

How to find the shortest route between two points based on cost surface?

I have two locations: (A) starting point and (B) designation. Also I have a slope raster. I want to find the cheapest path between these two locations based on the slope (it is more expensive to ...
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2answers
538 views

How to enable GRASS plugin in QGIS 1.8.0 (Linux Mint 13 - 64 bit)?

Every time I enable GRASS plugin in QGIS (Plugins -> Manage Plugins -> GRASS), I got a message: Exception - G_getenv(): Variable GISDBASE not set. I googled and found some information here but don't ...
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143 views

Atmospheric correction for RapideEye without atmospheric parameters

I'd like to perform an atmospheric correction of my RapidEye images but metadata do no include atmospheric parameters required to use the 6s algo implemented in the Orfeo ToolBox. Is there a solution ...
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2answers
392 views

Flow modeling and FOSS GIS; lahars and HEC-RAS

What are the options for FOSS flow modeling of dilute debris flows in QGIS or GRASS? Have you, or can you refer me to studies where the authors, tested these models/plugins/functions/etc. for use in ...
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1answer
71 views

Adding additional nodes to network in Grass GIS

I have created a network in Grass GIS (using v.net, nodes option). I then want to "disrupt" the network (i.e., create some road blockages) and add in nodes to the new line ends where road blockages ...