Questions tagged [qgis-grass-plugin]

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19 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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0answers
109 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 ...
1
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0answers
43 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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8 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 ...
3
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1answer
73 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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0answers
34 views

i.pansharpen does not work

Running Grass 7 plugin inside QGIS 2.18 on a mac OS 10.14.2. Trying to perform pansharpening on landsat 8 imagery. Algorithm i.pansharpen - Image fusion algorithms to sharpen multispectral with high-...
2
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1answer
344 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 ...
2
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0answers
41 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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0answers
76 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
259 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
56 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
127 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
181 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
87 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
23 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" for 1 star ...
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1answer
65 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 ...
1
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0answers
43 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 ...
2
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2answers
2k 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/...
2
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0answers
77 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 ...
1
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1answer
100 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 ...
1
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1answer
91 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 +...
1
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1answer
281 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 ...
2
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0answers
73 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 ...
1
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1answer
526 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
65 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/...
5
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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 ...
4
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1answer
957 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
758 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
221 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
100 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 ...
3
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0answers
66 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 ...
1
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0answers
42 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
396 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
457 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?
1
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1answer
163 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
145 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 ...
1
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0answers
97 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 ...
1
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0answers
68 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
155 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.
3
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1answer
148 views

QGIS Graphic Modeler not including all GRASS algorithms - How to include v.out.ogr?

I'm using QGIS 2.18,12 with the GRASS module 7.2.1 on Windows. When building a model in QGIS , I am not able to see all the algorithms possible under thr GRASS module, that are indeed available within ...
2
votes
1answer
237 views

PyQGIS GRASS r.reclass from Processing without result

I would like to reclass raster image with PyQGIS command from the Python Console. It runs without error but nothing is created. I have tried a lot of codes from here, but nothing is working. from ...
1
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0answers
84 views

GRASS within QGIS - can I access grass modules through shell?

I have QGIS/GRASS installation and I would like to do my process workflow through shell in Ubuntu. It is raster vectorisation -> selection by value -> saving as shp. I have done first step by gdal ...
1
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2answers
312 views

v.in.dxf not working properly in GRASS toolbox in QGIS 2.18.11

I am using the GRASS v.in.dxf tool from the GRASS plugin to import some contours in QGIS. Everything seems fine, but the tool does not import all the contours. There are no additional options in this ...
1
vote
1answer
68 views

Applying advanced parameter settings with RQGIS?

I am working on stream network delineation with GRASS 7 in RQGIS, the 'r.stream.extract' algorithm in particular. However, the algorithm returns erroneous result when the Advanced parameter, "v.out....
2
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1answer
494 views

How to know stream order in QGIS on output of r.stream.extract

I have stream order created over DEM using r.stream.extract , which gives 3 output files: stream_raster - raster map stores extracted streams. stream_vector - extracted points for each stream ...
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0answers
114 views

Missing v.stream.order of GRASS in QGIS processing tool

I want to use v.stream.order of GRASS in QGIS for stream but it is not available in QGIS processing tool. How to add that in processing tool QGIS version 2.14.17-Essen
2
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1answer
184 views

cannot start grass modules in gqis 2.14

When wanting to use the different modules in GRASS 7.2.1 I get this error. The version of qgis is 2.14.17 on 64 bit windows. I already checked that grass can find the right provider folder path. Who ...
3
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0answers
147 views

Using GRASS v.rast.stats: Rast stats layer not correctly generated

I want to use the GRASS tool v.rast.stats for extracting information from raster data. I need average, mean, number etc. for each of the 15 polygons. When I run the tool, following message appears at ...
2
votes
1answer
240 views

GRASS in QGIS - ' Cannot read raster map region' (running r.lake.xy)

I want to use the GRASS function r.lake.xy on a DEM that I have. I load the DEM raster into QGIS, it is not georeferenced. Then I create a New Mapset. I set Projection Not defined. I either leave the ...
11
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1answer
942 views

r.mapcalc does not give output in QGIS

For a while now I have been trying to use r.mapcalc from the QGIS Processing Toolbox. However, the algorithm does not give me any output. I have tried several raster layers and different expressions, ...