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....
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2answers
39 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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23 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 ...
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1answer
27 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 ...
4
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1answer
61 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
29 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
34 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 ...
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2answers
41 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
18 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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1answer
15 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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31 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 ...
4
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1answer
106 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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8 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
16 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. ...
3
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0answers
51 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 ...
2
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2answers
56 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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0answers
36 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 ...
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1answer
39 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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16 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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30 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
24 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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1answer
18 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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1answer
23 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 ...
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1answer
25 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'...
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1answer
27 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 ...
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1answer
26 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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1answer
25 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
45 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
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1answer
34 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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1answer
51 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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37 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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34 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 ...
3
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1answer
67 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 ...
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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 ...
5
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3answers
158 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 ...
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0answers
19 views

Problem with i.landsat.acca on GRASS

I have a problem with my Landsat Tree Cover Continuous Field. The images are fully of clouds and shadows, so unreadable. The problem is the following: when I try to use i.landsat.acca to remove ...
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2answers
43 views

Error installing addons in GRASS 7.0.2: File is not a zip file?

When I attempt to install an addon in GRASS Setting->Install Extension from Addons and select the addon i want from the list (r.stream.order) i get the following error: "ERROR: File is not a zip file: ...
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1answer
27 views

How to calculate stream order in GRASS 7.0.2?

I would like to calculate Strahler's and other stream hierarchy from my input raster but I am not sure how. This manual suggests tat I should use r.stream.order command, however in version 7.0.2 "...
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1answer
72 views

Positive Topographic Openness - do any FOSS tools (other than SAGA) provide this?

I'm looking for a FOSS GIS tool to provide Positive Topographic Openness on 32-bit Ubuntu. (which rules out ArcGIS) Normally I use SAGA GIS for this, but my Ubuntu setup is a bit messed-up after a ...
0
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1answer
18 views

R.patch creating enormous file size

I'm using r.patch (within QGIS, GRASS 7) to patch two Float32 rasters both of which have a respective filesize of under 200MB. When I save the memory layer raster created by the r.patch function, the ...
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0answers
15 views

Grass Gis i.atcorr for Aerial data

Can Grass GIS i.atcorr module be customized for Aerial sensor? Attempted for Aerial sensor which has altitude of 13km. but module is failed .if the satellite altitude is changed to 100 km, module is ...
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0answers
24 views

Raster Precision QGIS

I am using r.patch extension in QGIS to join a number of LiDAR tiles, some of which overlap hence i am carrying out this task before utilising in a hydraulic model. R.Patch works fine, however the ...
1
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1answer
21 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
42 views

OS X Yosemite: copy / paste into shell GRASS 6.4.4. within QGIS 2.14.0

I want to know How to copy/paste into GRASS 6.4.4. shell within QGIS 2.14.0. I'm working with OS X Yosemite and the right mouse button doesn't work neither shortcut (cmd+c/cmd+v)
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2answers
29 views

How to export vector file in GrassGIS to QGIS

I am using GrassGIS to analyze watershed. I created a stream vector extracted from raster elevation data, how to extract the stream vector file so I can open it using QGIS?
2
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0answers
26 views

How do I merge a point attribute table to a polygon attribute table in QGIS or GRASS?

I have a point layer containing the following data: I want the following polygon areas to be added to the point attribute table as all the points occur inside the various features of the polygon ...
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1answer
60 views

How to design a flood with water elevation on a specific point?

Actually I have to know the flooding area caused by a rise of the water level due to the implementation of a dam. So I would like to know if there is an extension or any tool in QGIS or GRASS which ...
4
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1answer
287 views

Cannot locate GRASS plugin in QGIS 2.14.1 on Linux

I am trying to load the GRASS plugin in QGIS but it is not shown in the plugin manager (no matter if I turn on experimental and deprecated plugins). Under processing / options / providers GRASS GIS 7 ...
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1answer
16 views

Grass GIS animation tool: zoom in to area of interest

The Grass GIS animation tool is great, but I'm struggling to be able to zoom into an area of the original rasters. Do I have to clip the rasters to achieve this, or can I use the advanced section of ...
2
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1answer
111 views

Cost Distance Map in QGIS

My question is very similar to Cost Distance Analyst In QGIS? However, I'm looking for a means by which I can create a raster displaying the cumulative cost of each pixel to a specified destination ...