Questions tagged [qgis-grass-plugin]

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27 views

r.watershed options using QGIS?

I am using QGIS 3.10 and the integrated GRASS plugin. I am trying to run r.watershed but I do not understand where I can pass in more parameters & flags to the r.watershed task. There are tons of ...
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9 views

“..does not contain a valid set of GRASS 7 modules.”, how to fix?

Using 3.10.8-A Coruña, installation with GRASS tools. I am trying to run Grass' r.water.outlet tool and getting this error: This algorithm cannot be run :-( The specified GRASS 7 folder "C:\...
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54 views

GRASS Tool r.stats.zonal for QGIS 3.14 Pi is not working in batch mode

I am trying to calculate the averages and standard deviations of the pixels of a group of 31 vegetation index rasters calculated from Landsat images, but only where these rasters intersect the ...
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1answer
34 views

Create GRASS 7.6 environment in PyQGIS [closed]

I am working on PyQGIS in QGIS 3.10 (Windows). My goal is to create a GRASS environment to be able to run modules like r.in.gdal among others. but i can't find the way to execute the modules. I have ...
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1answer
77 views

I am running a processing PyQGIS script with grass i.pca but I am not getting results in my output folder

It runs without problem but I don't get the expected pca bands, my output folder is empty, I don't know what to test. path ='C/Users/Manuel/Documents/INPUT' output='C/Users/Manuel/Documents/OUTPUT' ...
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0answers
18 views

QGIS Grass-plugin output does not match the CRS of input files nor project CRS

My project CRS and raster layer are EPSG:31467. However, when I use for example r.to.vect to create a polygon from the raster, the created vector layer has an unknown CRS and is a little bit off (does ...
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72 views

QGIS 3.10 LTR GRASS tools not working

Having difficulty with the new LTR GRASS functions. Typical workflows that worked in 3.4 LTR but not 3.10 LTR: -Open RGB mosaic -Use the raster calculator to extract the red channel -Use r.texture ...
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33 views

QGIS GRASS tools output has only “cat” column in attribute table - missing full attribute table

Using the GRASS Tools plugin in QGIS 3.10.2 with GRASS 7.8.2 I have imported a series of layers and used the "v.overlay.or" algorithm to "union" them. This has worked successfully many times and once ...
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0answers
76 views

Using GRASS and v.split with QGIS

I have been working with QGIS for a few years now and am just now having issues with the GRASS module. Ultimately, I am just trying to split a line (river) into 100m segments, and have found the ...
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2answers
45 views

QGIS GUI showing nothing on loading a GRASS mapset

I have GRASS 7 plugin installed with QGIS 3.4.2. I downloaded the Alaska QGIS sample dataset and followed these steps to load the dataset into QGIS. When I expand the alaska location and load the ...
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48 views

How do I split polygon into line segments?

My question exactly matches with this one : How do I split polygons into line segments? but the solution is outdated, I am not able to find v.type.bl option under the grass dropdown in QGIS 3.8. ...
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1answer
143 views

QGIS GRASS using v.drape FileNotFoundError: No such file or directory: '/usr/local/Cellar/osgeo-grass/7.6.1_5/grass76/etc/lock':

I'm running QGIS 3.8.3 and am trying to use v.drape. When I run it from the processing toolbox, I get a FileNotFoundError that's pointing to a strange /usr/local/Cellar/osgeo-grass.... folder. I'm ...
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1answer
123 views

GRASS: r.to.vect outputs empty layer when creating lines

I am trying to convert a binary raster to polyline using r.to.vect in QGIS 3.4. It keeps giving me an empty output, however. This is my input raster: And I am expecting an output (more or less) like ...
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513 views

QGIS GRASS plugin not found?

I have seen this question come up before and have tried the related fixes as best as I could but nothing seems to work. I am running the most recent LTR of QGIS, 3.4.8 but my GRASS plugin cannot be ...
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0answers
100 views

GRASS r.sun returns “ERROR: insol_time and incidout are incompatible options”

I'm trying to measure irradiance on a DEM using the r.sun tool in QGIS 3.6. I have grids for the elevation (EPSG:32735 - WGS 84 / UTM zone 35S), the slope and aspect (EPSG:4326 - WGS 84). I've tried ...
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12 views

Inner workings of GRASS reclassification on QGIS. How does it work with multiband rasters?

I have a 33 band raster layer I need to reclassify. I tried using GRASS module inside QGIS and it worked out fine, except that it outputs a raster with a single band. Which band of the 33 did it ...
4
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1answer
125 views

Find radius of curve?

Using QGIS with GRASS I have found a route through r.drain but it has many sharp curve. the maximum radius of curve allowed to me is 176m. Is there any to reduce the curve sharpness to 176m or at ...
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2answers
815 views

GRASS not working in QGIS, standalone

*Running QGIS 3.6, GRASS 7.6; have both Python 2 and 3 I'm trying to run a GRASS algorithm in QGIS, and none of the GRASS tools are working. GRASS also isn't working in the standalone version. I have ...
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0answers
53 views

Do I need the standalone GRASS app if I have the GRASS Plugin and Processing toolbox enabled in QGIS? [closed]

What processing abilities does the standalone GRASS GIS application have that aren't available in the QGIS GRASS plugin/toolbox? I'm trying to understand whether you would need/want the standalone ...
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104 views

GRASS function “V.net.centrality” Error env: python3: No such file or directory

I am using QGIS 3.4 (just updated) on a Mac OSX Mojave 10.14. I am trying to use the grass function "v.net.centrality" but I keep getting an error. The error is ... env: python3: No such file or ...
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1answer
1k views

r.series - no output 'ERROR 6: SetColorTable() only supported for Byte or UInt16 bands in TIFF format.!

Using grass tool 'r.series' (average of 2 raster files) with QGIS 2.18.28 works correctly. If I use this tool in QGIS 3.4.4 I get an error message: Processing algorithm… Algorithm 'r.series' ...
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0answers
63 views

Slope rasters - different results from different tools

I'm calculating Least Cost Path (LCP) within QGIS 2.18. The first step is to produce the slope raster from the DEM. Using r.slope in GRASS produces excellent results where I can go on and finally ...
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1answer
197 views

r.mapcalculator

I am using QGIS 2.18.25. I'm struggling to use r.mapcalc to calculate the ndvi for a workbook project. R.mapcalculator is shown on the workbook I'm using and seems simpler to use. Is there a plug-in ...
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0answers
328 views

Distance calculation with v.net.path in QGIS 3.2

I have 3 layers: origin and destination point shapefiles and network line shapefiles. I want to calculate the shortest path on the network between the origin (250 features) and destinations (20 ...
3
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1answer
137 views

Deleting floating lines from network using GRASS 7 in QGIS

I'm trying to find a way to remove floating line segments from a road network shapefile. Is there a relatively fast way to identify and delete these features? I've been using GRASS 7 in QGIS to ...
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0answers
25 views

Building graphs between two point layers

I am trying to run a script to find the shortest routes between two sets of point layers (Blue star and Green dots) in QGIS using road network. I am able to use GRASS gis "v.net.distance" ...
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1answer
82 views

Error - Grass 7 doesn´t run because isn´t not sucessfully installed

I am having problems to run GRASS7 from the processing tool. Always run the following error that is not corrected instaled. I ve reinstall QGIS several times, even tried different versions,as also ...
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0answers
59 views

Working with GRASS gis in pyQGIS

I am looking for a way to loop through GRASS gis v.net.distance in QGIS. I want to iterate over all the 3 layers which has multiple features at the same time, and print the shortest distance for each ...
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2answers
4k views

GRASS GIS Plugin not loading in QGIS 3

When starting up QGIS 3.2.2 (also tested with 3.2.3), I get the following message in the "Plugins" Log Message Window: 2018-10-18T08:03:48 WARNING Failed to load C:/OSGEO4~1/apps/qgis/plugins/...
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0answers
174 views

r.series GRASS algorithm in QGIS 3.2 output no-data image

I'm trying without success to calculate a standard deviation image from 4 input images. I already used the r.serie algorithm in 2.18 to calculate an averaged image. Know after upgrading to 3.2.2 on ...
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1answer
138 views

Adding GRASS module to QGIS 2.18.21

I did a module in grass wich I called r.out.haralickFeatures.py. I did a .qgm. I can't get the parameters rigth. #!/usr/bin/env python #%module #% description: Compute asm, contrast, var, idm and ...
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1answer
132 views

Grass averaging raster not working with: Could not read georeferenced file error

I am trying to average geotiff using grass files using r.external and r.series. The geotiffs are georeferenced with wgs84. The command is below. grass74 g.proj -c proj4="+proj=longlat +datum=WGS84 +...
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1answer
399 views

Find distance between point layer and lines layer in QGIS?

All the answers were for one point and one line, But I'm talking about one point and multiple lines, and for older versions of QGIS. I have two shapefiles including one point layer and multiple lines ...
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0answers
84 views

No attribute table or values in QGIS 3.2 Grass toolbox plugin output files

Using the Grass toolbox within QGIS 3.2 (and previously 3.0) when I import any files and overlay them, then use the "View Output" option (button), the resulting file has the correct polygon areas ...
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1answer
649 views

GRASS 7.4.1 in QGIS 2.18

I am a new user to QGIS and GRASS. I want to use v.centerline so I opened GRASS as administrator on Windows 10 and I went to the gui of g.extension and successfully installed v.centerline. I opened ...
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0answers
74 views

Can't get GRASS 7 V.kernel.vector to work on QGIS 2.18.14

I have reinstalled GRASS multiple times, with all of the necessary listed programmes to install beforehand (e.g. GDAL), and it won't work. The error comes up - GRASS was not found in '/Users/Shared/...
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1answer
1k views

Getting log error about default locale settings when using GRASS with QGIS?

I downloaded python 3.6, installed it, dowloaded QGIS 3.0.2, installed GDAL, then QGIS, then opened QGIS and tried to use GRASS processing tools. Initially I got the following error: env: python3: No ...
6
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1answer
1k views

QGIS GRASS Processing Not Working on MacOS?

Recently upgraded to QGIS3 (3.0.2) for MacOS (High Sierra) and encountered GRASS (7.2.2) issues. Tried adding a custom variable and now when running GRASS algorithms (e.g. r.reclass) I get the ...
2
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1answer
1k views

How does “Minimum Size of Exterior Watershed Basin” work in r.watershed command in qgis 2.18.12?

I have delineated the watersheds from DEM using r.watershed command. I have specified the Minimum Size of Exterior Watershed Basin as 1500. I have read the description of r.watershed as well. I am not ...
1
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1answer
229 views

QGIS GRASS error

I just installed QGIS 3 (after trashing the QGIS 2 app) on my macOS High Sierra. The application has been working well besides this error message that comes up when I try to use certain GRASS modules. ...
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0answers
116 views

solve Topology error in Grass using QGIS?

I want to build a raster from a vector layer by using "v.to.raster.attributes" in QGIS but its not working and give me an error to build a topology using v.build. I build it but after that i have no ...
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0answers
72 views

How to determine Kc value and apply it to r.sun?

As outlined in this link ( r.sun delievering unrealistic Values ) to get realistic values of kilowatt / meter-2, you must multiply the results by a "clear sky factor (Kc)". The link comments recommend ...
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0answers
63 views

Error “std::exception” in GRASS GIS via QGIS

Does anyone know what this error means? I am using the GRASS GIS plugin in QGIS and I have imported a road layer (vector) using v.in.ogr.
3
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0answers
781 views

Travelling Salesman in QGIS using GRASS

I would like to use the travelling salesman algorithm in the GRASS plugin in QGIS. I have a points layer (3 points) and a road layer. I have connected the 2 together using v.net and I am given this: ...
2
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1answer
699 views

r.water.outlet is returning blank raster in QGIS

I am Getting error "Ignoring point outside computation region: 77.0072,12.2529" while deliniating watershed using r.water.outlet in QGIS. What am i doing wrong?
2
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1answer
241 views

How to remove a map in QGIS GRASS Plugin

In QGIS Desktop 2.18.14 with GRASS 7.2.2, I started cleaning vector layers and it worked nicely. Issue: every time I load a shapefile onto GRASS Plugin by v.in.ogr (v.in.ogr.qgis), it creates a map (...
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0answers
211 views

Using QGIS modules on Android Studio [closed]

I've been working on an Android app (using Android Studio 3.0) that utilises certain supported GRASS GIS modules that are available on QGIS. It uses the module in conjunction with open source raster ...
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0answers
154 views

Missing Grass Toolbox plugin running QGIS 2.18.13 [duplicate]

I am running QGIS 2.18.13 with Grass 7.2.2[1? ... can't remember which number was shown ... see comments below] installed via the OSGEO4W installer on both Windows 7 and Windows 10 (64bit). (I have ...
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0answers
69 views

qgis-grass-plugin7 problem updating 2.18.12 ->2.18.13 (win10-linux) [duplicate]

after updating qgis to 2.18.13 version (and GRASS from 7.2.1 to 7.2.2) via OSGeo4W advanced setup on win10 (and via repository on linux mint 18.1) the qgis-grass-plugin7 has disappeared from the list ...
0
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1answer
182 views

Grass toolbar for QGIS 2.14.18

The GRASS plugin toolbar appears incomplete in QGIS 2.14.18. I can open the mapset but I'm not finding how to load (open) an existing layer.