Questions tagged [grass]

GRASS GIS (Geographic Resources Analysis Support System) is a free, open source geographical information system (GIS) specialized in handling raster, topological vector, image processing, and graphic data. GRASS GIS is a high performance analytical GIS and remote sensing with focus on modularity. Users can process both day-to-day data as well as massive time series.

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13 views

GRASS function r.fill.dir not working on specific DEMs

I'm using QGIS. The function r.fill.dir is not working on a few DEMs I'm working with. With other DEMs, it works. I attached the log report and one of the troublesome DEMs. You can see my QGIS ...
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11 views

Correct measure unity for slope and aspect in order to work in QGIS with "r.sun.insoltime"

I'm using QGIS 3.10 and I should create a raster that shows the hours of sunlight referring to a given day for my province. r.sun.insoltime (Fig. 1, sorry it's in Italian but I traslate) to work asks ...
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1answer
67 views

Extracting peaks and cols from a DTM raster and convert them into point shapefiles (QGIS)

I’m trying (again) to find an automatic way to extract peaks and cols from a DTM raster (derived from LiDAR surveys). By “peak” I mean simply the cell with the highest value of a neighbour of cells; ...
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35 views

Cannot connect to PostGIS database with GRASS, but can connect with psql with the same credentials

I am trying to connect to a PostGIS database (hosted in a docker container) on a remote server with GRASS. I am able to connect with psql and confirm that the table is there (IP redacted): psql -h x.x....
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73 views

Running the GRASS algorithm in standalone Python code using the PyQGIS processing module

What is the right way to import GRASS algorithms for a standalone Python script? I tried the solutions (solution1, solution2), but they didn't help me. Here's the code that doesn't import GRASS ...
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23 views

QGIS GRASS decoding error

As many others, as I found out, I to have a problem with GRASS possibly due to location (Czech Republic, Middle Europe). This is what I get: QGIS version: 3.20.3-Odense QGIS code revision: 495fbaec Qt ...
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27 views

Finding GRASSBIN on Linux

I am installing GRASS on linux. I have managed to download source code and compile and can now run grass from the command line to open GRASS and start a session. I am trying to run python scripts ...
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23 views

How to fix qgis-ltr-bin-g7.exe has stopped working error?

I need to create a dem from a contour shapefile and have been following the youtube video: Generate DEM from contours in QGIS by QGIS world. I load my projected shapefile, made sure Grass7 plugin was ...
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16 views

Finding libraries for GRASS Installation Linux

I am installing GRASS on Linux. I have gotten as far as running Make in these instructions: https://grass.osgeo.org/grass78/binary/linux/snapshot/INSTALL I get this for multiple libraries: error while ...
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21 views

Installing GRASS on Linux

I am installing GRASS on Linux using source code and the ./configure file to create a standalone python script. I have been following instructions and installing relevant code like proj4 and GDAL and ...
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34 views

Cannot create new mapset in QGIS 3.4.6

I activated the grass 7 plug in, but get the following error: GRASS intit error: GRASS was not found in 'C:PROGRA~1/QGIS3.4/apps/grass76' (GISBASE), provider ans plugin will not work. I also cannot ...
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35 views

Shaded relief / Hill shade - GRASS vs GDAL and QGIS

I tried generating shaded relief / hill shade maps using different algorithms in GRASS and QGIS. It was found that r.relief of GRASS produced more realistic terrain shading compared to GDAL Hillshade ...
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71 views

Using v.clean crashes QGIS

I am working on a shapefile depicting English administrative divisions in QGIS 3.16.15. I began first by using the 'Fix geometries' tool to remove invalid geometries. Then, I used the topology editor ...
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36 views

QGIS and GRASS: r.in.gdal "View output" produces "Unavailable layer! Layer data source could not be found"

I'm quite new to QGIS and I'm working with QGIS 3.22.2-Bialowieza and GRASS 7 package, I use macOS Monterey 12. I have a few vectors and rasters I need to transform to GRASS format in order to ...
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Errors Running Some Commands in GRASS Standalone Script

After much struggle I have managed to get a GRASS standalone script run outside of GRASS. I can successfully get an output from running some commands, while others give a very unclear and unhelpful ...
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172 views

QGIS Union is slow. How to speed up or which alternative to use, creating the same output?

I have two polygon layers which I want to union. One layer (1) is just one big feature, the other (2) contains 250’000+ features. Layer 1 was created this way: Several polygons --> fix geometry --&...
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40 views

SAGA or GRASS tools for RUSLE LS factor in QGIS

I need the LS grid for an area for RUSLE calculation. I ran both SAGAs Slope Length from Terrain Analysis - Hydrology and GRASS's r.watershed. The resulting LS factor grids are completely different. ...
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13 views

Import GRASS Modules into QGIS script stops script running

I am running a QGIS script in a standalone script which installs some modules from GRASS, which works, but the script stops running at that point. The code looks something like this # A bunch of sys....
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63 views

Calculating interactions between 2 viewsheds using R

I have one shapefile with locations of an animal and one street layer. First I created viewpoints on the street (every 10m) and created one cumulated tif ("street viewshed". Now my plan is ...
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45 views

QGIS: v.rast.stats not adding columns

In QGIS (3.16.14-Hannover), I have a layer of polygons as well as a raster layer, and I would like to compute for each polygon the average value of the corresponding raster area. As far as I gathered, ...
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24 views

'Use Layer Extent' not available in v.voronoi

I want to follow the accepted answer to the question, "Voronoi Diagram on a given polygon using QGIS". However, in my QGIS (3.16.14-Hannover), in v.voronoi I don't have the option 'Use Layer ...
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22 views

Python won´t open

When trying to open QGIS 2.18.22 on Windows 10 Python won´t open. All ready tried reinstalling other versions, and only version of QGIS 3 and onwards are able to work. The thing is that in this newer ...
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111 views

Getting errors on executing GRASS v.distance tool in QGIS

I have 2 shapefiles. One is a route and another one are the points along this route. I need to get the distance along the route. When I try to execute GRASS v.distance algorithm I get these errors: ...
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18 views

GRASS r.patch inputs not working in QGIS

I am trying to use GRASS r.patch tool in QGIS 3.18.3 The inputs section is greyed out and says 0 inputs selected How do I fix this?
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1answer
54 views

How to downsample a GeoTIFF in QGIS using GRASS

I need to downsample a GeoTIFF image. I have been trying to test this using a simple example like using the following r.samp.res dialog. (I know I could also export the TIF file directly following ...
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12 views

Grass Graphic Model v.net.distance Not Accepting point layer in From or To fields

I have a point and network layer connected in Grass GIS via the graphic modeler. I am trying to find the shortest path between the first point (ROUND=0) and every other point (ROUND != 0) on the same ...
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84 views

Error: Algorithm not found using grassprovider in PyQGIS standalone script

With QGIS 3.22 the GRASS algorithms got its own provider (grassprovider.Grass7AlgorithmProvider) and are no more part of processing.algs. Knowing this, in a standalone pyqgis-script I am trying to add ...
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29 views

How to bulk ASC files into GRASS

I am trying to import some LiDAR files (.asc) into a binary raster map layer using the r.in.gdal module from GRASS. As I have multiple files to import, I would like to batch import them. It is ...
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1answer
112 views

Installation path: GRASS and SAGA tools not running in QGIS 3.18+ (win 10)

I'm running QGIS on windows 10 and have a problem running GRASS and SAGA tools. The problem appears only when using QGIS 3.20 or 3.18. Using QGIS 3.16 on the same machine, using the same dataset and ...
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44 views

Using a bat file to run r.report on large number TIFFs

I need to process a large number of TIFFs or ASC that are also large in size, I was wondering if theres a way to run a bash script to call on r.report from GRASS to get the stats for my rasters and ...
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8 views

Grass GIS v.net connect fails only in Graphic Modeler

I am connecting a network and point feature within Graphic Modeler in Grass 7.8.3. This works fine in the console when running manually, but fails in Graphic Modeler with the error "ERROR: Layer ...
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52 views

QGIS GRASS problem

I need to use GRASS extension for my project but I am not able to due to an error that is not limited to me. I am getting this kind of error: Traceback (most recent call last): File "C:\OSGeo4W/...
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16 views

Working iteratively on GRASS in R environment

I would like to realize a bicubic spline for many shapefiles. Following the indications on this post,enter link description here I obtained my results and export it from GRASS to folder. Now, I would ...
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22 views

r.denoise - pyproj not found

I am trying to run r.denoise but receive an error message: "pyproj not found". MacOS, GRASS GIS 7.8.5; r.denoise was installed from local drive, as g.extensions failed. Mdenoise is installed ...
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82 views

Finding distance between points inside a region

I have several points (long, lat in EPSG:4326) in a region like this: and I would like to find a way to estimate the average distance between all points inside the region with a command-line tool ...
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1answer
16 views

Accumulated drainage area using r.terraflow

I am trying to compute the accumulated drainage area (flow accumulation) using the GRASS' r.terraflow algorithm in QGIS (QGIS 3.20.3 and GRASS 7.8.6RC2 were installed using the OSGeo4W Network ...
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24 views

GRASS R.viewshed.cva error -->Python (r.series) for folder

I am trying to use r.viewshed.cva to create viewsheds for over a hundred thousand of points. It actually works fine, I am getting over a million files but when it tries to combine all of them into one ...
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1answer
19 views

Problem during GRASS working session in R environment

I have a series of shapefile like those are in the attached folder. I would like to realize for each column of those shapefiles a bicubic spline. I would like to use for this operation GRASS into an R ...
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24 views

GRASS Hough transform issue [duplicate]

Via GRASS I installed the Hough transform. I start the Hough transform but it doesn't give any rendering time and the rendering doesn't finish. The image I used; (Canny edge detection applied image) ...
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12 views

Problem with GRASS7 extension installation

I am trying to install v.transects extension in rgrass7, but the error message says access is denied. I am running r from the only one account I have on this computer which is the admin account. Is ...
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1answer
24 views

Why some flow direction cell of GRASS r.watershed have no data value?

Using r.watershed inside QGIS, I am getting no data value along some streams for flow direction. I tried the r.fill.dir and for the same raster it does not give any no data value for the same cells (...
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1answer
54 views

Issues with projection when using RGRASS7

I have just started using rgrass7 and getting error messages when I try to use readRAST. Please see below initGRASS(gisBase="C:/Program Files/GRASS GIS 7.8", mapset = "PERMANENT", ...
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1answer
35 views

Using line split (v.split) in QGIS

I’ve been trying to split lines with certain length to extract those vertices. Alt ought, when I try v.split and it creates a new shapefile, nothing is drawn and the attribute table is empty. I had ...
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31 views

Selfmade XYZ Data can't be loaded by GRASS Algorithms

I'm trying to use my own measurement data for multiple GRASS algorithms in QGIS. When I use a 1m raster from the internet everything works perfect. But if I use my own data I get an error stating that ...
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36 views

Use GRASS functions in QGIS that are not available in processing toolbox

QGIS contains many Grass functions but not all. I want to use r.accumulate in QGIS but there is no tool available for it. Is there a way to use these GRASS functions in QGIS directly or with pyQgis ...
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15 views

QGIS v.net not working for certain lines data

I am trying to make a connected network using the v.net GRASS tool. It has worked for 3 vector line layers but is not working for two. I am not sure what the problem is. I used the same settings for ...
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27 views

Outputs of "Strahler Order" and "Channel Network and Drainage Basins" different despite same threshold

I ran the Strahler Order and the Channel Network and Drainage Basins tools both with threshold at 8 and using the same filled DEM. The results differ as shown below. Strahler Order raster (only ...
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22 views

"Channel Network & Drainage Basins" works if the filled DEM is from "r.fill.dir" and not "Fill Sinks (Wang & Liu)"

I'm using QGIS Desktop 3.16.9 and was doing this video https://youtu.be/2Ub0c7Ss-T4. The instructors used "Fill Sinks" and then the "Channel Network & Drainage Basins". When I ...
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20 views

GRASS QGIS v.vect.stats returns NULL for all polygons

I'm running v.vect.stats from Grass using the processing toolbox in QGIS to take an average of a point layer attribute for points falling within a set of polygons. After running the algorithm a ...
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48 views

r.fill.dir not working

I am using QGIS 3.16.2 "Hannover" with GRASS 7.8.4 on Windows 10 64 bits. Im doing a watershred and r.fill.dir is not working, the message is the common the following layers were not ...

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