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 iterate over multiple shape files using g.region

I have a shapefile called Ahmednagar. I have daily rainfall data from 1997 till 2008. I want to sum total rainfall from 152 till 273 day for each year for 1997 till 2008. This is how I do it. g....
2
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0answers
26 views

Comparison of % change in two photos with GRASS

I have two aerial photos of the same location taken at two different dates. Is there a way to compare the % difference between those two images using GRASS or is there a better tool? Sorry, also if ...
2
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2answers
141 views

Grass tools not working in QGIS 2.14.3-ESSEN, OSGEO4W

Windows 10 QGIS 2.14.3-ESSEN OSGEO4W install (current) 64-bit Processing toolbox. Grass tools do not work Neither 6 nor 7. 6 makes sense as I do not see OSGEO4W installing it but 7 tools are ...
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1answer
33 views

Fast, simple assignment of flow directions to flats in GRASS

I have some enormously huge DEMs which I'd like to assign flow directions to. These DEMs are guaranteed to have no sinks, just flat areas. It seems as though the only ways of assign flow directions ...
2
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2answers
62 views

GRASS 7 environment setup for Python

I would like to use some GRASS functionality from a Python programme. With GRASS 6 this required the set up of various environment variables, as detailed in the GRASS Wiki. I am trying a similar ...
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1answer
46 views

Exception using PyGRASS: “No module named 'core'”

I am trying PyGRASS on Ubuntu 14.04. I have GRASS 7 installed from the UbuntuGIS PPA: $ dpkg -l | grep grass ii grass 7.0.4-1~trusty1 ...
2
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2answers
116 views

What are the meaning of Grass drainage direction values from r.watershed

In Grass r.watershed the D8 drainage directions generated from r.watershed are -8. -6.-4.-2, 2, 4, 6, 8 (-1 No Data) What actual directions are these? For example in ArcGIS I know 128 is up and so ...
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1answer
74 views

Stratified Random Sampling Tool

Is there a way to produce a certain amount of random points over different classes in a raster in QGIS? I have extensions such as GRASS or GDAL, ...
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1answer
38 views

GRASS/QGIS- “buffer” created with DEM analysis- how to avoid it?

I have, to start, a DEM raster and a shapefile, with random created points, within a given polygon. The DEM raster was clipped with that same polygon. With the DEM raster, I used GRASS to perform ...
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1answer
21 views

System locale settings error creating GRASS location from Python

I am trying to use GRASS 7 from Python without explicitly creating a location. I am starting with the script provided at the GRASS-Wiki. This script tries to create a new location in the /tmp/ folder ...
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1answer
56 views

Create GRASS Mapset in QGIS 2.12

How do you create a new GRASS mapset in QGIS 2.12? The GRASS panel has only the Open GRASS Tools button.I don't see any way to actually create a GRASS mapset in QGIS.
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1answer
21 views

CRS different after r.reclass through QGIS different than source raster

According to the properties, my output raster is in a different projection than the input after running GRASS r.reclass through QGIS. Does anyone know if this is just a fluke and I can simply select a ...
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0answers
36 views

Setting up a simple catchment area for shops using QGIS?

I would love to set up a catchment area around simple dots on a network map. The catchment should be separated by different range-areas (50, 100, 200m), just like isochrones. I tried the GRASS plugin ...
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0answers
41 views

cellinp and cellout in v.vol.rst

I am trying to use v.vol.rst in Grass 7.0.4 to interpolate temperature values considering elevation. The answer of Grass to my attempts is: WARNING: Unable to create cellout raster map without cellinp ...
4
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1answer
132 views

v.kernel is missing under Processing Toolbox GRASS GIS 7 commands

I installed the QGIS Standalone Installer Version 2.14 (64bit), that automatically contains GRASS 7.0.4. I created a map with several layers and rasters in the program called QGIS Desktop 2.14.3 with ...
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1answer
76 views

GRASS 7 Cost surface and elevation points development

I'm a new to GIS and I'm trying to develop an optimal path across an area by using GRASS 7 features. It is very similar to the task given here. The problem is that I don't have any data with ...
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1answer
29 views

Neighborhood analyses with GRASS/QGIS using ASTER GDEM

I have a problem related with this question (Old question without answer: R.Neighbors with large neighborhoods?). Basically, I want to estimate roughness of a given area, for which I was using QGIS, ...
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0answers
11 views

Importing TRMM bin data in GRASS

I am trying to download daily data from TRMM from this website ftp://disc2.nascom.nasa.gov/data/TRMM/Gridded/Derived_Products/3B42_V7/Daily/1998/ For example, If I download any .bin file from the ...
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1answer
22 views

What causes the comand 'd.vect map' to fail in GRASS-GIS?

I have been having problems with visualizing my data in GRASS-GIS. I imported my .shp file into the software following all instructions and, after that, I selected the layer I wanted to visualize. ...
2
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2answers
92 views

QGIS Can't run any GRASS tools from processing toolbox

MAC OSX 10.11.13 New machine clean install of QGIS from Kyngchaos Installed Current version 2.14.2-Essen When I try to run a GRASS command e.g. v.clean I get the following error: This algorithm ...
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1answer
22 views

How to solve “features were not reachable” warning message using v.net.distance in GRASS

I'm using GRASS 7.0.4 under Linuxmint 17.1 KDE. I need to build a raster with the shortest distance from every pixel to a city following a road. I have two shape files, the city (point) and the road (...
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0answers
54 views

Multiple watershed delination with QGIS

I am trying to divide a DTM model in subbasins but I have set specific outlet points for the subbasins, and not to use a thershold. Is there a tool similar to r.water.outlet but with multiple outlet ...
3
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1answer
140 views

Atmospheric Correction for multiple Landsat-8 scenes

I need to perform an atmospheric correction for Landsat-8 data and can't find a solution. There is a very limited amount of information dealing with L8-correction methods in a comprehensive way, that'...
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1answer
51 views

Error in r.thin Qgis GRASS : Input raster must be of type CELL

I am getting the following error from QGIS GRASS GIS r.thin module ERROR: Input raster must be of type CELL. The input file is a simple file of 0 and 1 that represent a drainge network. I obtained ...
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0answers
27 views

Downloadable pdf format of GRASSGIS 7.0 manual [closed]

Can anyone help with a link or something that could enable the download of a pdf version of the grassgis manual? I am having a hard time trying to convert the html version into printable pdf. Nkeze
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0answers
36 views

Negative values in r.watershed flow accumulation

I am trying to process a DTM by using r.watershed in QGIS 2.14.3, with the GRASS GIS toolbox. It should be the file named: "Number of cells that drain through each cell". I get some negative values, ...
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0answers
26 views

How to install r.mcda.electre on GRASS

I have downloaded r.mcda.electre addon from the following link: https://wingrass.fsv.cvut.cz/grass71/x86_64/addons/grass-7.1.svn/r.mcda.electre.zip But I can not install it with the latest version ...
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3answers
9k 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, ...
2
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1answer
265 views

How to set QGIS 2.14 on OS X to use GRASS 7

My current QGIS installation (2.14) on OS X 10.11 is set up to work with GRASS 6.4.4. I am guessing this is the default GRASS version that comes preinstalled with the QGIS package maintained by ...
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1answer
30 views

Exporting multiple layers to single dxf file using Grass GIS?

I'm very new to Grass GIS. I need to export multiple vector layers into a single dxf file (required in order to import into another application). However, I can't see a way of selecting more than ...
3
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1answer
221 views

GRASS via Processing Toolbox doesn't work in QGIS 2.8.3 on Mac?

I am quite new to QGIS and working with the external applications such as GRASS. When trying to launch a GRASS tool from the processing toolbox I get the following error: Missing dependency. This ...
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1answer
31 views

Error operating on file using grass

from grass.pygrass.modules.shortcuts import raster as r gscript.run_command('g.region', raster='C:\\Users\\rit\\Documents\\PhD\\Projects\\Intensity\\input\\2008_cdls\\MI\\cdl_30m_r_mi_2008_albers.tif'...
2
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1answer
800 views

Visualizing a LiDAR point cloud in 3D with GRASS?

I'm new with QGIS and GRASS so I'm sorry if there is a straightforward answer for this question but I can't seem to get it done. I've imported a point cloud into QGIS from a datafile. Now I'd like to ...
3
votes
1answer
97 views

Changing way r.cost and r.drain modules work?

Look at the picture #1. This is my cost surface raster that has only 2 values. Area restricted for path to cross (red one) and area that is free to go (yellow one). As I need it and as I undestand how ...
2
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1answer
29 views

GRASS 7 raster map calculator

I am new to GRASS and am trying to use it because I can't afford the Spatial Analyst extension in ArcGIS. I am trying to remove all of the values in a NDVI raster less than some value to exclude ...
5
votes
3answers
165 views

Smoothing method for big polygons

I'm looking for an alternative to 'snakes method' for smoothing very big polygons, which I created from SRTM elevation datasets. The problem is that the smoothing is getting stuck after a while with ...
0
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1answer
28 views

r.patch results in a blank map in GRASS

I have a collection of tiles downloaded from the EDINA Digimap service, in asc format. I imported these into GRASS using the r.in.gdal function, and they appear in the display screen as expected. I ...
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1answer
49 views

How to merge adjacent polygons with no common attributes in GRASS?

Many topics are talking about merging polygons based on their common attributes, but few (or none) give a real answer to location-based merging problem. Explanation. Here is a fraction of the base ...
2
votes
1answer
146 views

GRASS plugin for QGIS2.10 missing [duplicate]

I have installed installed qgis2.10 from source on Centos6.6 however the issue i'm facing is that i am missing the grass plugin form the gui. I have checked the plugin manager, its not listed there. ...
0
votes
1answer
74 views

R equivalent of GRASS r.grow?

What is a good R equivalent of the GRASS function r.grow? The closest I've been able to find is the script suggested by whuber in response to Creating randomly shaped clumps of cells in a raster from ...
2
votes
1answer
38 views

QGIS - best fit to the sectoral terrain (SRTM 30m resolution data)

i need a help to find out the Slope of "best fit to the sectoral terrain". here is in details about the area of calculation. we have a reference point, from the reference point our sectoral area ...
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6answers
3k 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
39 views

GRASS gis: treating certain cells as starting points in mapcalc

I am attempting to calculate the vertical height from horizontal of every point on a slope. I want to use stream beds (the lowest points in my DEM) as my starting spot, with the horizontal plane ...
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1answer
53 views

Question about Using r.mapcalculator in Python console

According to the following conversation: Using r.mapcalculator in Python console? I tried: ##NoData Background=name ##RASTERLAYER_BAND=raster ##nodatabackground=output raster import processing ext ...
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1answer
206 views

Using r.mapcalculator in Python console?

I'm trying to use the r.mapcalculator algorithim in a python script, but I'm having problems in using the r.mapcalculator to tranform a raster layer with float values into integers. Using the ...
3
votes
1answer
88 views

GRASS r.reclass QGIS 2.14. error: “the following layers were not correctly generated”

I am getting a strange error message when running the GRASS r.reclass algorithm. The error states that: "The following layers were not correctly generated *reclassified You can check the ...
0
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0answers
37 views

n-dimensional visualization software

I am using Grass 7.04 standalone. I have made a 3d view of dem raster. How can I have a high resolution image file of it to work with photoshop? It seems that the only tool to have it is Nviz but it ...
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1answer
28 views

How to open .jp2 with GRASS 7.0.3

Does anyone know if I can use Grass to open a .jp2 image file? I am aiming to do some image classification on the image and when I try to import the image into the program a stream of errors comes up ...
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0answers
7 views

plotting a proportional sized snowfall fall pin ( also the numerical number) for 150 kal local ng positions on a us map

just starting to learn Grass. Need to learn how to have a usa outline map. (Is this spearfish?) On the map place pins ( for a given latitude and longitude) proportional in height for annual ...
3
votes
1answer
338 views

How do I open GRASS layers in QGIS

I'm quite a newbie to QGIS and GRASS.. I have installed QGIS 2.10.1 with GRASS 6.4.3 on my Windows 7 laptop and wish to open GRASS layers in QGIS. If I got it right, you can use the QGIS built-in ...