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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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 ...
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2answers
302 views

Automatically apply topology rule to only selected portions of a .shp file?

I am looking for some examples/tutorials on how to apply a topology rule to only a selected portion of a shp file using a script in ArcGIS/GRASS. Using ArcGIS seems to always require an interactive ...
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1answer
54 views

installing grass71 on centos6

I am installing grass71 on centos6 , i have the following message after running grass71 [bachir@nexus ~]$ grass71 Starting GRASS GIS... g.gisenv: /lib64/libc.so.6: version `GLIBC_2.14' not found ...
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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 ...
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3answers
3k views

Is there a way to automate the preprocessing of LANDSAT data?

I'm currently enrolled in a remotesensing course, using LANDSAT data. Part of my course is about standardizing the scenes based on radiance values. I assume that because this is such a tedious task, ...
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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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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
152 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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3answers
221 views

Looking for large GML files containing vector polygon data

I have few vector data files with 500 to 700 MB GML files. But I am looking for files larger than these preferably 1 GB, 2 GB. It would be helpful if somebody can provide some pointers regarding the ...
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1answer
49 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 ...
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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2answers
50 views

Keep “no data” tiles with r.reclass rules

Working in QGIS 2.14.0-Wien. I want to reclassify a raster with the r.reclass GRASS 7 tool, but want to keep the "no data" tiles as "no data". I understand that I need to create a text "rules" file ...
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0answers
19 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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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
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 ...
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3answers
2k views

How to interpret GRASS v.kernel results?

GRASS manual reads: v.kernel - Generates a raster density map from vector points data using a moving 2D isotropic Gaussian kernel ... Ok, but how do I interpret the results? I understand that ...
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1answer
48 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 ...
2
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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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2answers
327 views

r.topidx error: required parameter output not set

I'm calling GRASS r.topidx from QGIS 2.2.0. I can get other tools to work on the DTM, for example r.watershed. But r.topidx I get the Oops message: Oooops! The following output layers could not be ...
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 ...
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1answer
25 views

Set region with rounded values/coordinates

How do I set a region update with rounded coordinates. I usually set my region from a puffer around my points of interest and round up the north and east coordinates and round down the south and west ...
2
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1answer
46 views

Problems to use v.what.vect in GRASS7

I have problems to use the function v.what.vect and I'm not sure what is the issue. I have a simple forest polygon and try to determine if a point is in the forest or not. # check the output of the ...
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2answers
387 views

Error in r.terraflow

I used r.terraflow.short in GRASS, but it displayed this error: r.terraflow.short elevation=raster_bulacanElevation \ filled=raster_bulacanElevationFlooded1 \ ...
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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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1answer
184 views

Area of a Cross Section GRASS GIS 7

I have a task I would like to solve with GRASS GIS 7, if somehow possible. I want to create a cross section from a landslide - and would like to calculate the area of that cross section/profile. Any ...
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1answer
68 views

Calculating percentage of cells which are lower than site in Grass GIS?

In GRASS GIS: I have a shapefile with 300 hundred of sites (with height values for each point), and want to calculate the percentage or number of cells (of a given DEM) which are lower than the ...
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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 ...
3
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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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71 views

Speed optimization of shadow computation with grass gis r.sun

I am trying to optimize the speed of r.sun to compute shadowed area on a DTM at 1m resolution. My current area is 3.39 km² but my final area will be 450 km². The r.sun wiki say that pre-computing ...
3
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1answer
119 views

Cannot open r.viewshed on Grass 7

I cannot open the r.viewshed tool in Grass 7.0.3. I am using the 64-bit version on Windows 7. The error message is given below: Traceback (most recent call last): File ...
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0answers
49 views

r.sun from QGIS toolbox doesn't give realistic value about the hours of insolation

I have a problem with the GRASS module r.sun when I run it in QGIS. I would calculate the hours of insolation in a specific site during a specific day. When I ran the algorithm "r.sun" from GRASS, it ...
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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 ...
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 ...
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2answers
90 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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3answers
27 views

Grass 6.4.3 v.rast.stats: Calculate only one value

I am using the grass (6.4.3!) function v.rast.stats to calculate the mean value of rast values over polygons. The tool is somewhat slow and I actually only need the mean value. Is there any ...
5
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1answer
292 views

Grass NVIZ has no output in QGIS 2.8.1 ubuntu 14.04

I am trying to use the Grass7 NVIZ algorithm from the QGIS 2.8.1 toolbox, on ubuntu 14.04. I have enabled Grass7 in the QGIS processing preferences. I have compiled Grass7 from source, and Grass ...
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0answers
36 views

Python error when using r.reclass on raster with no CRS

I have a set of GRID data (directory of .adf files) that I'm trying to reclassify in QGIS. I'm using the GRASS r.reclass function to try to reclassify the layers, but GRASS keeps failing and ...
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0answers
9 views

Can grass 7.0.3 pansharpen Landsat 8 spectral bands [duplicate]

Can grass 7.0.3 now pansharpen Landsat 8 rgb spectral bands. The last post in 2013 said that a programmer was working on it.
4
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1answer
140 views

basin creation GRASS vs. flow direction

I have a strange behaviour in QGIS with GRASS tools. I am trying to create basins in the alp region and use he SRTM3 data. As I can see on the flow direction raster the SRTM3 data seems to act nice: ...
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0answers
22 views

QGIS and GRASS 7 integration [duplicate]

I want to integrate QGIS 2.12.3 or 2.13 with GRASS 7, but I still haven't been able to do so. Can someone please tell me how can I do this with a stable QGIS version.
0
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1answer
56 views

GRASS parser() error

I'm trying to use GRASS on python 2.7, but I'm having some problems at setting my script on IDLE, then I'm getting an error at parser() function: Here is my script: import os import sys gisbase = ...
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0answers
25 views

My OSM country roads network is not routable [duplicate]

I need a routable shapefile in order to execute pgrouting algorithms. I download a national zip from http://download.geofabrik.de/europe/greece-latest.shp.zip and import the roads shapefile in my ...
3
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1answer
656 views

How to get the Flow or directional raster map using GRASS?

Aside from using r.fill.dir in GRASS, is this the script to produce the Flow or directional raster map? Is the output for the script the following graphic? ...
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0answers
34 views

GRASS unable to download any extension from GRASS Addons

I'm trying to install some add-ons to GRASS, but each time I try to download an addon, I'm getting the same error: g.extension.py extension=v.autokrige ...
5
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2answers
2k views

How to correctly install QGIS 2.8.3 with GRASS plugin on Ubuntu 14.04?

I already tried to install QGIS 2.8.3 using the procedure described on: http://www.qgis.org/en/site/forusers/alldownloads.html#debian-ubunt, but grass-plugin do not compare on plugin list! I tried ...
2
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2answers
86 views

Missing v.in.ogr module of GRASS in QGIS Processing toolbox?

I am a new user to QGIS/GRASS and I am having a problem utilizing GRASS. I have several files that I generated in QGIS that I want to import into GRASS so I can use some of the Grass modules. ...
2
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1answer
75 views

windows can't open the file, v.in.ascii

I am using GRASS 7 for windows, and I'm having trouble running v.in.ascii, although I'm fairly sure I've run it successfully before. When I run v.in.ascii, I get an error: Windows can't open this ...
2
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1answer
29 views

Using wild cards in GRASS to remove files

I have a bunch of files on a GRASS location, all named temp_something, that I want to delete. I tried to use the g.remove tool using the multiple option and typing temp* in, but it doesn't work out, ...