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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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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320 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
226 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 ...
9
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1answer
817 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
164 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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1answer
179 views

How to get the direction raster from r.walk or r.cost

I am trying to use r.cost and r.walk and r.drain to calculate the shortest path from an archaeological site to the nearest basalt source. I am using all this algorithms with the processing toolbox (I ...
5
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1answer
288 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
66 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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163 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
968 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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3answers
224 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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2answers
161 views

Grass GIS 6.4.3, How to create a .PTS file

I'm trying to export a raster map in order to use it in the Flo-2d program. This program needs a .pts DTM file, do you know how I can create it? Alternatively, I can use a XYZ file looking like this ...
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1answer
856 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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1answer
152 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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1answer
726 views

Map Algebra - Grass GIS (r.mapcalc) merge two raster with NoData value

I have a slope raster and a road raster. The black pixels in the road raster are NoData values and the pink pixels have a value of 1. They don't cover exactly the same area. I want to create a new ...
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2answers
735 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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223 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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225 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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174 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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1answer
292 views

How to perform GRASS v.rast.stats via QGIS

I have been using qgis for the last few months. I got interested in using GRASS tools through QGIS. I wanted to compute zonal statistics for a raster surface for a given polygon layer. I loaded the ...
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1answer
173 views

Removing Image Stripes / Scan Line errors

I have some seabed bathymetry data derived from seismic reflection profiles in a 2.5D dataset (closely spaced lines). The data was gridded by another worker in SMT Kingdom suite; I'm not familiar ...
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2answers
138 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
185 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
2k views

Viewshed / Line of Sight analysis- as a batch process?

I wish to carry out a line of site analysis similar to the subject in here (preferably within QGIS): Visual Impact Assessment in QGIS or GRASS Scenario: I have two points, A and B. Point A is a ...
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55 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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2answers
969 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 ...
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32 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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24 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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1answer
363 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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166 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
196 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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2answers
445 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 ...
4
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1answer
501 views

Is it possible to use GRASS GIS in Python stand alone scripts?

I am trying to find a least cost path script for Python. I came across r.drain from GRASS GIS. Is it possible to use GRASS GIS in a Python stand alone script? If so where can I download the bindings?
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1answer
560 views

GRASS in QGIS not working (windows XP)

I am unable to use GRASS algorithms in QGIS 2.0.1 (on windows xp). I've already configured the GRASS path. The algorithms seems to work correctly (I cannot see errors in the log), however in the end ...
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1answer
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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0answers
355 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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1answer
143 views

How to set opacity for GRASS layers using command line?

In the process of learning GRASS, I am finding that I can learn many of the command-line methods that I need for scripting tasks from using the wxGUI, as it conveniently shows most of the underlying ...
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1answer
90 views

How to set partial transparency for GRASS layer?

I am trying to style layers in a GRASS monitor such that they are partially transparent. I'm guessing that there's a module for that (d.shadedmap seems close), but I haven't found it. I need a ...
2
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0answers
233 views

How to Install GRASS Addons to use in QGIS [duplicate]

WIN 7 QGIS 1.8.0 GRASS 6.3.4 I want to use r.viewshed in QGIS. therefore i want to install it in GRASS by using the GRASS interface. Followin Error appears. g.extension.py extension=r.viewshed ...
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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 ...
1
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1answer
149 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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2answers
107 views

Neighborhood analysis based on occurrence of value

How can I do, either in ArcGIS, grass or another tool, the following: for each cell (pixel), if there is at least one cell with value '4' in a neighborhood of 5 cells around it, reclassify that cell ...
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2answers
808 views

How to set output resolution for gdalwarp to that of source file?

I have a large raster, which I want to re-project and crop for a new location that I'm creating in GRASS. I seem to have gotten the re-projection and cropping right with this call to gdalwarp: ...
2
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3answers
439 views

Raster map in different zone () than region ()

I am new to QGIS (just installed QGIS 2.0.1) and am having problems running any spatial analysis tools. I followed the instructions on how to call GRASS tools into QGIS, but when I try to run the ...
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1answer
359 views

How to debug “Unable to load GDAL library” error in QGIS 2.0?

I have a problem with r.surf.contour. I create a DTM with v.to.rast.attribute and then use the r.surf.contour and it works fine in QGIS 1.9 but with QGIS 2.0 doesn't work. I have a contour shapefile ...
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1answer
208 views

grass algorithms no longer run in QGIS/Sextante

I used to be able to run GRASS algorithms in QGIS 2.0 via Sextante (Ubuntu 12.04) but not anymore. Initially I would double click on any grass algorithm and the execution would stop with: "WELCOME TO ...
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1answer
110 views

Calling GRASS 6 in GRASS 7 (shell)?

I am running a shell script for batch processing in GRASS 7 (calling it with sh [...sh] in the command line window), which creates a series of rasters through classifications, raster calculator and ...
0
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1answer
203 views

How to import and patch multiple ASTER files in QGIS?

I'm a new user and just began with GRASS, where I learned to import 30x30 resolution ASTER files and then patch them (the six I'm working with) into one map. On QGIS, it doesn't appear that there's a ...
2
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2answers
433 views

How does GRASS handle multi-channel images (e.g. landsat)?

I am trying to understand how to use multi-channel images (e.g. landsat or the land-cover data provided by Natural Earth). I am hoping that someone can confirm or correct my interpretation of the ...
3
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1answer
768 views

How to cluster Raster data

I have thousands of Raster data concerning the ice coverage at the pole at different times (days) over several years. Now I would like to perform a cluster analysis. I want to split the data into ...