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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Adding a GRASS module manually in QGIS (Mac OS X)?

I am trying to add a precompiled non-standard GRASS module to QGIS 2.0.1 (MAC OS 10.9.1, using the binaries by Kyngchaos). Adapting the instructions here ...
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84 views

libfreetype-6.dll lost when using GRASS command line

Update#1: Following the instruction of Sorin Călinică, I have installed libfreetype-6.dll using the OSGeo4W Network Installer, and the command d.rast can launch successfully. I am using GRASS ...
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398 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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1answer
117 views

How to iterate GRASS region definition?

I am using GRASS r.skyview command (v.7, Windows) to determine "urban canyon effect" on pollution due to the presence of buildings. The command nicely works, unfortunately I need to process a very ...
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25 views

Multiply vector categories

I have imported a Vector map into GRASS GIS. There are some problems with the topology and some polygon areas overlap. I used v.clean to break overlapping polygons and now I have multiple polygons ...
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38 views

display 3D raster/vector in GRASS 7.0 from command line

I am using GRASS 7.0 on ubuntu linux 12.04 x64. I am working through some GRASS tutorials and am able to get a 3d raster to show up when I use the GUI. However, I cannot get the command line interface ...
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34 views

How to install grass addons when offline?

Can anyone tell me how can I install GRASS (v.7) addons on a windows PC when offline? I manually downloaded the files from http://svn.osgeo.org/grass/grass-addons/grass7/ and copied: - the .py file ...
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1answer
311 views

How to identify line intersection in QGIS when I have more than 2 lines?

I am trying to identify where overlaps exist between multiple shapefiles. I would use the intersect tool, but it only allows me to intersect two layers. I have over one hundred individual line ...
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252 views

In GRASS in QGIS, what do I do if “NVIZ module not found”?

I was a on a Windows system using GRASS in QGIS when the error below occurred. NVIZ module not found I wonder how I can solve this problem?
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214 views

Cleaning shapefiles with islands in GRASS GIS

This may be very simple, but I'm new to GRASS GIS. I have a large shapefile containing global species ranges, which needs topological cleaning. I imported this into GRASS GIS 6.4.3 using v.in.ogr (a ...
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2answers
213 views

Creating square buffer in qgis

How can I create a buffer with square ends along a line segment in qgis? I've buffered lines using v.buffer in the GRASS plugin, but the -c option for square ends is not exposed in that interface. ...
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1k views

Rubber sheeting in GRASS or QGIS

We are in the process of getting our property boundaries corrected and a side effect of this is that we need to move any assets that have been drawn relative to the property boundaries, so they are ...
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1answer
307 views

Topology problems with QGIS/GRASS

*edited file links below I'm working on several NGO projects at the moment, all of which are reliant on being able to use a district level map with some 490+ features, and I am running into some ...
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50 views

Removing multiple categories from GRASS vector feature

Pardon my lingo if this is not entirely correct - I am a software developer, not a GIS person. We're working a project that uses v.overlay to merge a map of slopes with a map of soil tests to produce ...
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16 views

How to obtain stream segments from complemented image(raster data)?

I have raster data in tiff format, i want to extract stream segments from the complement of original raster data. I am able to extract stream segments from original raster data, but not able to ...
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52 views

header information is missing from image, after writing using opencv

I am doing complement of an image using open-cv python, while writing the image, open-cv is not writing the header information in the complemented image. my image data are in TIFF format. i am doing ...
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77 views

Is it a good idea to use GRASS Algorithms for Geoprocessing in a Server Environment?

I´m designing a web-service to run in a server environment that will do some geoprocessing actions to datasets uploaded by users and send the results back. I´m programming in Python, and so far I´ve ...
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10 views

GRASS Add Vector Point

I need to do a viewshed analysis using GRASS. I've got the DEMs loaded; and I simply want to input several (2-4) points (like 41.12345N, 122.34567W from GPS). What is the simplest, most ...
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190 views

Merge two rasters with no data value

I have two rasters: Raster A and B. Raster A has has only values of 0. The white area in Raster B are No Data values. I want to merge them to one raster (Raster C). So basically I want all pixels in ...
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2answers
1k views

1'' DHM: Hillshade is too rough - how to “generalize”?

I got this hillshade from my DHM (I used the hillshade-module from qgis). For my purpose there is too much relief detail (roughness). How can I get rid of this in QGIS or GRASS? Thanks! Martin
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5answers
3k views

Large mosaic process failing - what are the options? software independent only focussed on result

I need to mosaic about 550Gb of tif imagery together and the software I have tried keeps failing. The area has been split into zones so that the smallest has approx 200 tiles. I have used the latest ...
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37 views

Debug/Improve Performance of GRASS v.in.ogr

I'm trying to import shapefiles (in this case, OpenStreetMap data) into GRASS (grass70-svn) using v.in.ogr; and it is painfully, brutally slow. At first I thought this was because I was using the ...
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62 views

Is there a tool to buffer features with more than one distance value in GRASS GIS?

I´m looking for a tool like Multiple-Ring-Buffer in ArcGIS, but for GRASS GIS to be able to buffer with different distances but only having to start the process once.
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57 views

Analysing a network distance to two or more points using GRASS or QGIS

I am doing a piece of analysis work looking at distances along a network in GRASS. Most of the analysis involves finding which parts of the network are within 600m of a series of points. GRASS does ...
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43 views

OSX: Installing GRASS addons in qGIS?

I would like to install r.stream.basins in GRASS through qGIS (2.0.1-Dufour). I tried using g.extension ext=r.stream.basins and got the error "the 'make' program is required. Please install first". ...
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20 views

grass: walking along vector line

I have a line vector which I converted into points with v.to.points. I need to get the coordinates of each point AS I WOULD WALK ON THE LINE. v.to.ascii appears to just use some other order, but I ...
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26 views

alignment of shapefiles in GRASS

I have two shapefiles below. One is in the state plane projection, and the other is not projected. In ArcMap the shapefiles line up perfectly. When I import them to my mapset (using the override ...
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1k views

How to find the watershed area for each point in the river network using DEM?

Update#1: Thanks, Micha, I have followed your instruction and successfully use the modules in GRASS. I use r.watershed to get the basin raster and the drainage line: and I use r.water.outlet to get ...
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118 views

Problems using GRASS GUI (d.rast and r.watershed)

Update#2: I tried the command in the function list above instead in command console, and I got this in command output: and it displayed nothing, showing the same error message in the command ...
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1answer
143 views

How to get additional subbasin areas designated by points in the river network?

Update 14/1/9:I follow this post:Watershed and Stream Network Delineation, and here's my workflow: use Batch Point Generation to create batch points related to designated points(green dots) Batch ...
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37 views

QGIS V. parallel command using GRASS

I cannot offset a line to a specific decimal place, (ie only whole numbers can be inputted) Am I missing something here??
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34 views

grass on ubuntu cannot import globalvar

I installed GRASS GIS 6.4.3 on Ubuntu Precise 12.04 by sudo apt-get install grass grass-doc, as recommended by the Wiki. It runs with the wxpython GUI, but when I use any command (like r.in.gdal or ...
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43 views

How to use the Cartographic Composer of GRASS 6.4.3?

Following on from my previous question (which was, again, how to use the Cartographic Composer)... I've got a GIS in GRASS. I need to print various bits of it. Problem is, it needs images on it ...
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837 views

How to use GRASS module to delineate watershed area?

Update#1:I changed to work under qgis 1.8, I only input the DEM file and run the r.watershed module, and I got this: I have a DEM file of one specified region, and I take the following steps to ...
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1answer
95 views

Importing SRTM Data into Grass

I am having issues importing an SRTM HGT file into Grass. I first made a new location as the instructions from this Grass Newsletter Tutorial states. I then went to the download site and downloaded ...
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2answers
59 views

How to produce maps with copyright imagery on it in GRASS?

I'm having some trouble with a GIS that I've got to produce. I work for a contractor and we'll have to produce maps to do the work for our client. The client has specified that if we print maps out ...
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55 views

gdalbuildvrt ------— Problems with binary rasters used by grass

r.in.gdal is used for importing tif images in grass environment and they were changed to binary by default. I am trying to make a stack from them but unfortunately grass does not see my rasters ...
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2answers
456 views

Why is this SRTM TIFF not visible in GRASS GIS 6.4.3?

I want to use interpolated SRTM data for Germany to generate an STL terrain map for use in a CFD application. My SRTM data comes from the OpenDEM project. SRTM data normally has voids, but this data ...
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145 views

When trying to convert an .e00 file into a shapefile with ogr2ogr, getting “ERROR 4: This looks like a compressed E00 file”

When I ran this command: ogr2ogr topo.shp flowe86hyp.e00 I got this error: ERROR 4: This looks like a compressed E00 file and cannot be processed directly. You may need to uncompress it first ...
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47 views

How to import r.in.gdal from WCS (only region extent)

Can I import WCS-Data only for the current region by r.in.gdal? I tried to import raster data from my WCS into GRASS GIS, using r.in.gdal as proposed in ...
2
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1answer
118 views

Temporal GRASS GIS framework

I am trying to follow the tutorial posted here. When I get to this part "Extraction of seasonal mean temperature" and run this code: t.rast.extract \ input=temperature_mean_1950_2011_seasonal \ ...
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1answer
53 views

Isolate the largest patch in a raster in GRASS?

I have a raster with a series of patches (contiguous areas with same value). How do I isolate the largest patch? I know I could run r.stats, look through the long list of calculated areas, figure out ...
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24 views

i.atcorr empty raster

I am recent GRASS GIS user who is trying to run the i.atcorr module to atmospherically correct a Landsat ETM+ image in GRASS 7 (on MacBook Pro, Mavericks OSX). This image has been already converted to ...
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1answer
148 views

How to begin with tool development for GRASS gis or QGIS GRASS

I wanted to begin with customized tool development in Grass GIS or QGIS grass. How should i begin in to develop the tool. I search a lot in google search engine for begin with tool development in ...
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2answers
73 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 ...
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2answers
405 views

How to set all pixels with value <= 0 to “nodata” in DEM raster?

I have a DEM raster with pixel values between about 3000 and -0.0003. I need to set all pixel with a value of 0 and smaler (<=0) to "nodata" (for later raster calculations and to reduce the ...
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78 views

Debugging r.neighbors error in Processing

I'm having similar problems withs some GRASS algorithms in processing plugin. On the one hand i have installed Ubuntu 12.04 with Qgis 2.0.1. In this machine when I run r.neighbors algorithm don't ...
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1answer
132 views

How to fix QGIS crashes when using GRASS toolbox?

I've installed QGIS 2.0.1 on Ubuntu 12.04. exactly as explained on qgis.org . Unfortunately QGIS crashes when trying to use any GRASS model (r.aspect as example): just opening QGIS, click on toolbox ...
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298 views

What is the best way to ortho-rectificate image from the plane?

I am very new in GIS and I am trying to ortho-rectificate my images. But after putting it on the map I see that results are not precise. We have images taken from the airplane, it's longitude, ...
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78 views

Which Landsat version is appropriate to imply a supervised classification with GRASS GIS?

I need to imply a supervised classification with GRASS GIS to find build-up areas. I want to avoid Landsat 7 images due to SLC problem. Can I use images of Landsat 8 or it's better to use images ...