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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131 views

How to change the raster color range in GRASS NVIZ?

I'm trying to create a 3d map in GRASS NVIZ from a GDEM (raster) and the range of colors that show the height of the terrain are very ugly, how I can change them? For example, I would like the low ...
2
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1answer
600 views

Integrated viewshed analysis

I need to do integrated viewshed analysis of a target with several observer locations. I am going to use r.viewshed analysis function in GRASS. With this function, it is possible to perform analysis ...
2
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1answer
339 views

OGR Python bindings

When I try to access one of the GRASS vector files through Python OGR bindings, it gives error: Here is the script code in Python 2.7.3 IDLE (GUI) in Windows 7. from osgeo import ogr ds = ...
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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. ...
2
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1answer
2k views

GRASS GIS: How do I run a batch (bash?) script?

I am in a GRASS database (in command shell), where I want to run a loop function. For example, I want to do an operation on many raster files that are in the database. I know this must be done through ...
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3answers
1k views

How to access vector coordinates in GRASS GIS from python?

Is there a way to iterate over lines and their vertices using python? I'm new to GRASS GIS, and it looks like there are ways to read raster (for numpy), but I don't see a direct way to access ...
2
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2answers
1k views

QGIS is not able to find GRASS. Choose the path of installation folder of GRASS

I've downloaded and then correctly installed QGIS 1.7.4 for windows (Win 7 64bit is my version) in C:\Programs\Quantum GIS. But everytime I start QGIS this popup appear: "QGIS is not able to find the ...
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2answers
749 views

r.mapcalculator and python again

I've been trying to write a script creating binary maps: a=raw_input ("enter a threshold") b=float(a) grass.run_command('r.mapcalculator', formula="**'base_map'>=b**", outfile='map'+str(a), ...
2
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1answer
550 views

How to import SpatiaLite data into GRASS?

How can I import SpatiaLite tables into GRASS? Are there any restrictions I should be aware of? How does GRASS cope with columns that don't have a specific type (Sqlite tends to create such columns ...
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1answer
69 views

Adding items to DEM in QGIS

Working with QGIS and Grass I would like to produce a ZTV. I have the bare land DEM happily ready to go but would like to add buildings and woodland to the calculation. Can anyone please point me in ...
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1answer
457 views

QGIS GRASS Missing Dependancy

I want to perform a view shed analysis in QGIS using GRASS 7 r.viewshed. When I double click on r.viewshed in GRASS GIS 7 commands in the processing toolbox of QGIS I get the following message: ...
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2answers
1k views

“Missing dependency.This algorithm cannot be run :-(” QGIS + GRASS Windows 7

Windows 7, OsGeo4W pack installed including QGis 2.4.0 and GRASS. I Qgis when i try to execute a GRASS geoprocessing algorithm i get this popup: "Missing dependency.This algorithm cannot be run :-( ...
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1answer
161 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 ...
1
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1answer
315 views

How to make GRASS and SAGA tools capable to use in QGIS?

As my title, I installed Qgis, GRASS and GDAL by osGeo4w package, and as I finish the installation, I want to use GRASS tool, I face this problem: But I already installed GRASS and SAGA, how to make ...
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1answer
155 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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0answers
151 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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3answers
221 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
200 views

contour lines from point shape attribute

I have a point shape file and one of the attribute refers to the altitude. Is is possible to obtain a contour lines shape file in GRASS?
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1answer
244 views

GRASS-QGIS Linking error

I need few customizations over grass and would use qgis gui for accessing grass. I am building qgis with grass enabled (WITH_GRASS=TRUE). While I am doing that I get the following. Any help is greatly ...
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0answers
177 views

i.maxlik cannot read i.class output signature file

I'm trying to perform a supervised classification using i.class. I'm then using i.maxlik, but this is returning the following error: GRASS 6.4.3svn (India_01):~ > i.maxlik group=test_group@test ...
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2answers
2k views

How to set cell size for vector to raster conversion in QGIS GRASS plugin?

I'm converting a vector (loaded in GRASS plugin in QGIS (1.7.0.-wroclaw) and would like to convert this to a raster with a defined cell size. At the same time I need a value from the attribute tabel ...
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2answers
616 views

How to import .flt files into GRASS?

I am trying to import a raster file (.flt) into GRASS. The raster file (.flt) was generated from HEC-RAS. The said raster format cannot be imported into GRASS (it shows the error "file not ...
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1answer
606 views

Win7 GRASS 7 & i.landsat.toar

Hello has anyone got experience running i.landsat.toar ? The output files I get are empty, the command takes but a moment to complete. However when run in verbose mode all the calculations are done, ...
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2answers
446 views

GDAL-GRASS building fails

When I run ./configure --with-grass=/usr/local/grass-6.5.svn/ I get the following errors: .......... checking for gdal-config... /usr/bin/gdal-config using /usr/lib/gdalplugins as GDAL shared library ...
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1answer
928 views

How to select a raster file that is under a polygon in a vector file?

I am using: v.db.select map=PHL_adm1 where=NAME_1='Bulacan' My vector map is over the raster map. I want to select the part of the raster map under the polygon(NAME_1='Bulacan') of a vector. Is it ...
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1answer
2k views

How to combine a vector and a raster file?

I want to combine a raster and a vector file. After combining, can I query on the resulting map to obtain a specific area? How?
0
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1answer
20 views

Overlaying of raster in GRASS for visualization?

I have generated insolation time rasters map in grass using r.sun module. How to overlay insolation time rasters over DSM depicting the color table for visualization?
0
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1answer
239 views

How to use python to set a variable to a value from a vector attribute table for GRASS

I'm adding to a python script for GRASS v.transects.py. I want to set a variable to equal a value from a field in the vector's attribute table using a for loop to cycle through each row. This is one ...
0
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1answer
369 views

d.rast problem in GRASS command line

Update#1: @gene, thank you for your reply and I type d.mon in command line, getting a popout GUI look like this: I choose the top three flags(-l, -L, -p), and I got this: And I don't know what to ...
0
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1answer
366 views

Can't launch GRASS GIS 6.4.3 GUI on windows 8.1

As title, I downloaded GRASS GIS from this website: GRASS GIS - Home, and I choose winGRASS 6.4.3 standalone installer to download. After I installed, I click on its icon: I can't launch it even ...
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2answers
390 views

GRASS algorithm r.los does not produce raster

After running the r.los algorithm through QGIS 2.0, I'm getting a 'Problem loading output layers' box which gives the following message: Oooops! The following output layers could not be open Output ...
0
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1answer
301 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, ...
0
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1answer
336 views

How to script map production in GRASS?

I'm trying to automate my production of maps with GRASS. What I want to do can be described in fairly generic terms: I have two layers (one vector, one raster), which will be identical in every map. I ...
0
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1answer
398 views

How to batch merge rasters using FOSSGIS tools?

I'm working with QGIS 1.8 (gdal 1.9.2) and GRASS 6.4.3...but on Windows 7. I "just" want to merge my raster. I've got a folder with 50 GTiff raster from Lidar data. The aim is to merge raster ...
0
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1answer
315 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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2answers
2k views

How to resolve missing Python module (importlib) for GRASS/Sextante?

I have installed the nightly build of QGIS 1.9 from Larry's Dakota Cartography site, and have downloaded the latest Frameworks from William's Kyng Chaos site. However, I am unable to install the ...
0
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3answers
2k 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 ...
0
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1answer
44 views

Why is this GRASS script (from GRASS WiKi) causing an error?

I'm trying to run a script from the GRASS WiKi to create a simple map using ps.map. I'm confused because it's generating an error that the output was not set, when it appears to me that it is set at ...
0
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2answers
233 views

Error from ps.map in GRASS. How to fix?

I'm trying to learn how to use ps.map in GRASS. I thought that running it in interactive mode from the command line would be a good place to start, but I'm getting the following error: > ps.map ...
0
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1answer
167 views

Problem running i.gensigset in Grass. Any ideas?

It just returns ERROR: Unable to create signature file. It doesn't say why... Anyone had this before and found a solution?