Questions tagged [qgis-grass-plugin]

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135 views

Layers from GRASS db won't load in QGIS 2.18.4 desktop

I have been learning QGIS online but now I am stuck at a module. I am supposed to launch a project that includes GRASS vector and point layers. However, when I do so I always receive the 'Handle bad ...
4
votes
1answer
865 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 ...
3
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0answers
63 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 ...
3
votes
0answers
356 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: ...
3
votes
0answers
141 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
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0answers
74 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 ...
2
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0answers
70 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 ...
2
votes
0answers
58 views

Generating ground control points with GRASS?

I want to find out matching ground control points in two images for auto georeferencing and grass manual says that i.points.auto will do the job. I am using Grass 7.2 but couldn't find this plugin.
2
votes
0answers
200 views

QGis 2.18 (and other tests on QGis 2.14) hangs with GRASS 7 editing session (OS Windows 8and 10)

I installed QGis 2.18 (64bit and 32bit versions) and i started a session with GRASS 7 in Windows 8 environment (the same thing I did on another workstation with Windows 10). I loaded a test layer with ...
1
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0answers
30 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 ...
1
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0answers
22 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 ...
1
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0answers
41 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 ...
1
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0answers
62 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/...
1
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0answers
96 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 ...
1
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0answers
39 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.
1
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0answers
82 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
vote
0answers
280 views

Linux QGIS 2.18.4 GRASS7 tools not working

GRASS tools are showing & GRASS 7 shows as activated in the Providers menu, but I get the "Missing dependency, GRASS isn't configured properly" message. How do I configure it properly? GRASS 7.2 ...
0
votes
0answers
68 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 ...
0
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0answers
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 ...
0
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0answers
21 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-...
0
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0answers
65 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 ...
0
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0answers
53 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 ...
0
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0answers
146 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 ...
0
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0answers
111 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