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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How to create water basins with given river network? [on hold]

I would like to create basins (and subbasins) for a given river network. The river network is not derived from a DEM, but from satellite imagery or maps. However, I do have a DEM as well. My initial ...
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19 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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11 views

grass log file for i.atcorr

Can anyone suggest me how to write log file for i.atcorr(for grass gis 6.4.4) which has been customized. i seen in grass gis 6.4.4 gui, log file tab is there and if required by user, it is writing log ...
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1answer
37 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 ...
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1answer
111 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
13 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
56 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 ...
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1answer
16 views

Matching Python and GRASS projection

I have a colleague producing maps with the following Python Basemap projection: from mpl_toolkits.basemap import Basemap m = Basemap(width=6000000,height=3900000, ...
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2answers
26 views

Issue running r.region in GRASS command line

I'm currently attempting to use r.region to preform analysis on a specific area of a raster image. I'm receiving Lat/Long data from the step before me, but I'm having issues use that data in ...
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1answer
21 views

To display custom data on a Shape file

I have a shape file which is a district map. There are close to 800 districts. There are around 30 funding agencies. There are 4 different health programs. The different funding agencies fund specific ...
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1answer
28 views

Is it possible to start the GRASS GUI from R?

I am using the rgrass7 package in R in order to work with GRASS GIS. After having set the needed enviornment variables, I can now launch a GRASS session from R and and work on my GRASS data using ...
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13 views

GRASS 7.0.3 - Script to automate multiple simulations?

I have a question I hope you'd be able to help me solve. I am working in GRASS 7.0.3 and want to conduct a complex analysis of Least-Cost Paths of the many-to-many type. Specifically, I do have my ...
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25 views

Problems with QGIS 2.14.1 and GRASS 7.0.3 [duplicate]

I been having problems with modules GRASS / GRASS 7.0.3 in QGIS 2.14.1 I did the installation with Standalone Installer QGIS Version 2.14 (64bit) QGIS-OSGeo4W-2.14.1-1-Setup-x86_64.exe My OS: ...
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42 views

Grass processing not configured in OSGEO4w QGIS 2.14.1

I get the below error when I try to use grass processing from within QGIS. The error is given on all commands and I have got this error on 2 machines. I am using windows. "This algorithm cannot ...
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2answers
139 views

QGIS 2.14.1 Processing Toolbox GRASS 7 .NVIZ Not working

I have a problem with the command GRASS 7 .nviz in QGIS 2.14.1 installed through QGIS-OSGeo4W-2.14.1-1-Setup-x86_64.exe.md5sum all GRASS commands work exept .nviz / nviz7 images: I test with ...
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19 views

Process road polylines to not overlap building polygons

Is anyone aware of a processing tool in Grass or similar which will find segments of polylines which overlap polygons in another dataset and reroute the polyline to avoid the collision? My problem is ...
3
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1answer
60 views

Convert xyz points to topography and calculate mean slope

I am working on point data (x, y, z) in meters from origin. I have between 24 and 35 points for each plot (10mx10m), with random locations. I would like to modelise topography over the whole plot in ...
2
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1answer
39 views

command r.stream.order not found in grass 7.0.3 how to install r.stream module?

I have installed QGIS 2.14.1 and GrassGIS 7.0.3 I found in OSGEO Grass wiki page a command that calculate Strahler's and Horton's stream order Hack's main streams and Shreeve's stream magnitude from ...
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2answers
23 views

What does the max_slope_length option do in GRASS r.watershed?

What does the max_slope_length option do to the r.watershed program in grass? According to the manual, it should limit the length of a stream. Does this mean a max_slope_length equal to the raster ...
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13 views

What does the blocking option do in GRASS r.watershed?

What does the blocking option do to the r.watershed program in grass? According to the manual, it should stop water from being routed past that location, but it appears to have no effect. I'm trying ...
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99 views

GRASS r.in.lidar tool generates incomplete rasters

I have been trying to import a huge LIDAR file (10.5) Gb to GRASS GIS using r.in.lidar. It does the task, but only for part of the image, as shown below: Canopy Height Model (CHM) generated with ...
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2answers
104 views

Where is the nviz tool in qgis 2.14 with GRASS 7.0.3?

I hope Im not blind but I looked in the grass tools (modules) and qgis plugins but couldnt find it. When i try to run nviz from GRASS the whole programme chrashes just before concluding. Its a ...
3
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1answer
62 views

How to use GRASS raster tools in the Processing modeler?

In the Graphical Modeler of QGIS, I don't see a way to import a layer into GRASS. The modules "import loaded raster" are not accessible in the Modeler. I want to use GRASS reclassify module, because ...
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1answer
42 views

Quantile in QGIS python Plugin

QGIS is very powerful when it comes to styling Vector Data. When it comes to Raster data, ArcGIS still has some advantages including Styling based on Quantiles. See my earlier post: For this I want ...
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1answer
58 views

Invalid Geometry, what's wrong with the geometry?

I am using QGIS (2.10) to make a growing zone map of the U.S. from some data I found online. I need to reshape to fit into a U.S. map, and I find it's easier if I break the shape into smaller parts, ...
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33 views

Calculate shortest paths for each output area in catchment through road network to a single point (i.e. store)

The title sums it up pretty much. I'm looking to derive trip distributions to a single store using population data and distance within a prescribed distance catchment. I have calculated the catchment ...
3
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1answer
67 views

Understanding intersection of GDAL and QGIS?

Background I'm starting a project that will be done entirely through Python, except perhaps at the end for visualisation. So far I've been doing it with ArcGIS and arcpy, but we'd like to move it to ...
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3answers
139 views

Why are the holes in my polygons not generalized?

I have one polygon layer with many holes. I would like to generalize it. I used v.generalize of grass. With it, I used chaiken algorithm. But, only the borders of polygons were generalized, the holes ...
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1answer
26 views

Pygrass reading raster issue

I'm tring to read a raster map from my grassData. I'm using this code import os import grass.script.setup as gsetup from grass.pygrass import raster gisbase = os.environ['GISBASE'] gisdbase = ...
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1answer
59 views

Reshape polygon to boundary of other polygon

I have two polygons. The first one has a white background and brown boundary. To othr has the pink background. how is it possible to reshape to first polygon to the boundary of the other polygon?
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1answer
155 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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29 views

Will Grass GIS 6s atmospheric correction take raster as input for atmospheric parameters

I am working on atmospheric correction using 6s in Grass 6.4.4 version(i.atcorr module). I want to use raster data set for atmospheric parameters. Presently I am creating an icnd (input ...
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1answer
50 views

Pygrass ERROR: Mapset is not set

I am using Pygrass in a a Python Grass GIS stand alone application. I am using GRASS GIS 7.0.3 on a Windows machine and Python 2.7.4. I am initializing a new Grass environment. I can work in this ...
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20 views

GRASS r.sim.water (ERROR: Required parameter <dx> not set)

Running r.sim.water (SIMWE) model: r.sim.water -t --overwrite elevation=elevation.10m@PERMANENT dx=elev2_dx@PERMANENT dy=elev2_dy@PERMANENT depth=depth160308_ niterations=90 output_step=1 fails ...
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35 views

v.net modules QGIS 2.14 OSX

the .net modules have been added to the toolbox for 2.14 but I can't see them running under OSX (10.11.1) using kyngchaos. I can see other Grass 7 tools but not the v.net ones. I know I can run these ...
3
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1answer
109 views

Why can't I enter decimals in QGIS r.water.outlet?

I am using the latest version of QGIS 2.14. I have a raster DEM file. I ran the r.watershed and it created all the raster layers for flow direction, stream, etc. My next step is to run ...
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1answer
49 views

Specify target elevation with r.viewshed in QGIS processing toolbox?

How do I specify the target-height in r.viewshed when using the operator through QGIS's processing toolbox? It doesn't seem to be available. Who should I contact to adjust the interface such that the ...
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1answer
22 views

v.overlay in GRASS

As I understand, v.overlay module can be used for polygons overlapping processes. Polygon clipping, union processes can be done. There are many algorithms for these operations. Which algorithm is ...
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0answers
26 views

GRASS r.watershed problems in QGIS 2.12

I have a weird error when using r.watershed in QGIS and I have depleted all my ideas. Yesterday it was working normally and generating all the files, then suddenly it stopped working and shows the ...
2
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1answer
370 views

QGIS 2.14 GRASS geoalgorithms don't work?

I instaled qgis 2.14 and grass geoalgorithms dont work. Only 160 geoalgorithms and should be 168. MsBox: Missing dependensy, It seems that GRASS is not correctly installed and configured in your ...
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2answers
49 views

Create a new GRASS database in R with CRS projection

How to create a new GRASS database in R with CRS projection? I am able to create a new one using the following code but it is not projected require(raster) require(spgrass6) ...
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2answers
43 views

whats wrong with my exported raster reclassify map in grass?

I'm trying to export a reclassify map in grass to a Geotiff format to pass it to DinamicaEgo platform. I have 6 classes in grass but when I export it, the exported map show me 255 classes and they ...
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1answer
55 views

QGIS: Grass Tools: Least cost path using r.drain generating flawed results

I am trying to use a combination of r.walk and r.drain in the QGIS grass plugin to model the most efficient path between two points, where cost is accumulated principally by movement over deeper ...
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2answers
56 views

Making a simple line- complex

I am trying to make my own version of code to generate elevation profile for a line drawn over a DEM and I got stuck very early on. As a simple use case: I have a line that consists of just two ...
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1answer
52 views

Sunshine hours duration calclulated from r.sun (GRASS Plug in) are same for diffrent date

Currently i am trying to calculate sunshine hours duration from r.sun (GRASS Plug in ) from QGIS 2.12. I want to calculate sunshine duration for 21 st jun and 21st December for same elevation data ...
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1answer
52 views

cells w/in search window GRASS GIS

I am trying to find all cells that are a certain distance and within a certain window from a cell of interest. For example: I want all cells in a distance of 10m within a search window of 10 - 40 ...
2
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1answer
81 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 ...
3
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1answer
107 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, ...
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2answers
93 views

GRASS init error in QGIS?

Every time when I start my QGIS I see the following message: GRASS init error: Problem in GRASS initialization, GRASS provider and plugin will not work : Module built against version $Revision: ...
2
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1answer
26 views

QGIS graphical modeler: how to automatically enter parameters in r.drain.coordinate tool

i am carrying out a cost least path analysis and i am using QGIS. The processing tools i am using are: r.cost.full and then r.drain.coordinate Considering i have more than 1000 layer to process ...