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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14 views

r.slope.aspect grass gis datum format on dx and dy analysis

I'm performing terrain analysis due to photovoltaic installation on QGIS with r.slope.aspect plugin. I'm interested in evaluate differently N-S slope and E-W slope based on the PV system I would ...
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3answers
40 views

Rescale Sentinel2 data to 8 bit

I need to rescale Sentinel2 data (both lvl 1C and 2A) to 8 bit, because of the requirements of a GRASS GIS module (i.histo.match) that only works with values from 0:255. All the documentation of ...
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2answers
17 views

GRASS - r.mask analogous for vectos

I am working with r.stats. My analysis is about overlap Extreme Climatic Events (ECE) raster map with mammals range maps. I used to do my analysis first creating r.mask on ECE map and then applying r....
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1answer
48 views

Error launching GRASS GUI : error message related to gcmd.py or gi_set.py

I am trying to run GRASS GIS for the first time. However, when I try to run GRASS (by clicking on the icon in the start-up menu), I get the following error message: > Starting GRASS GIS... ...
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0answers
26 views

How does grass r.viewshed take into account the Earth curvature?

Up to now I always had to do such analysis in a local Cartesian Coordinate System and on relatively small datasets, but today, I want to compute a viewshed analysis on a large raster DEM which is ...
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1answer
17 views

Installing GRASS >7.0 and its addons to use in R session

I am hoping to use the openSTARS package that relies on GRASS 7.0 within R. However, I do not understand how to proceed with the initial steps. From: https://github.com/MiKatt/openSTARS A functional ...
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0answers
32 views

I am getting an error running v.to.rast [closed]

I can see that this question has been asked in some other way before. Unfortunately, the advice given there does not help me. I am trying to run v.to.rast and the error message that I get is WARNING: ...
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1answer
33 views

Warning: skipping unsupported geometry type 'Compound Curve' when using v.transform

I am trying to transform data in QGIS from a DXF file. I keep getting the error: Warning: skipping unsupported geometry type. Compound Curve when I do a v.transform. Eventually, I want to store the ...
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0answers
23 views

Creating a GRASS addon that returns something when using read_command()

I am using grass 7.8.4. I'm calling commands externally using the Grass Python Scripting Library in Python. I wanted to know when you create an addon in Python how to end the addon script so that when ...
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2answers
45 views

Can't use simple GRASS modules in python (python script not found)

I am using grass 7.8.4. I'm trying to run some simple commands using the Grass Python Scripting Library in Python. For modules for which the source code is written in C++ or any other language than ...
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1answer
31 views

GRASS plugins not loading on Qgis 3.10.13 Coruña LTR

I have QGIS 3.10.13 LTR installed with the stand alone installer on a Windows 10 machine. In this machine I have also a QGIS 3.16.2 OSGeo installation. I can work perfectly with GRASS in my OSGeo4W ...
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1answer
30 views

r.watershed error in QGIS (3.16.2) for MAC

I'm trying to use the r.watershed tool, here is the error that is arising. I've tried changing the GRASS path to custom /Applications/QGIS.app/Contents/Resources/grass78 and it doesn't seem to work ...
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1answer
72 views

Generating Hough transform (Hough line transformation) of binary image using QGIS

How do I generate a Hough transform (Hough line transformation) of a binary image in QGIS? I tried in GRASS and I got Error: unable to fetch interface description for command I found from the link: ...
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0answers
25 views

Creating new mapset with Python and EPSG 4326 (Invalid north field 1N)

I am using grass 7.8. I have been trying to create a new location and then a new mapset in python. It works fine for any EPSG code except 4326. With EPSG 4326, when I try simple commands (like ...
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0answers
14 views

Deducing start and end of season information using r.seasons in GRASS GIS at 'Field' level

I would like to ask one question on using r.seasons in GRASS GIS. The information page on this function is available at https://grass.osgeo.org/grass78/manuals/addons/r.seasons.html The problem that I ...
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0answers
31 views

CalledModuleError: Module run None g.gisenv -n ended with error

I am trying to use r.horizon GRASS module(version GRASS 7.8) in Python script. But I couldn't able to access the grass modules. Everytime, I am getting the following error. File "C:\OSGEO4~1\apps\...
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1answer
26 views

Printing a multiline d.text in GRASS-GIS when using Python grass-session

Here is what I'm trying to do, but the text remain printed in one line. What is wrong? from grass_session import Session from grass.script import run_command with Session(gisdb="path to mygisdb&...
3
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1answer
72 views

Making vector geometries “Kiss” in QGIS

I am working with vector geometries that I recently simplified using the native:simplifygeometries method in the processing toolbox. I am pleased with the simplification but I want to "fill" ...
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1answer
35 views

PyQGIS loop of GRASS processing

I have many nc files and for each one I would like to create a tif file with the average of the bands using r.series of grass processing in QGIS. I wrote the code below but it doesn't work but no tif ...
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0answers
41 views

Understanding difference between osgeo4mac libraries and basic libraries (PROJ, GDAL, etc)

Is there a meaningful difference between osgeo-gdal and gdal that would make me choose the osgeo version over the basic version? The context here is that I'm trying to install grass on my mac (...
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1answer
37 views

QGIS: GRASS GIS plugin not accepting UTM point coordinates

I am using QGIS 3.16 with the GRASS plugin. I imported a UTM point cloud (x,y,z) and successfully generated a TIN surface based on it (using QGIS own functionality). But when I want to use GRASS v....
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1answer
33 views

“Raster map not found” error using GRASS r.walk

I'm using GRASS' r.walk for the first time, and I'm trying calculate the best path between two different points. I have a DEM (from SRTM) and a slope map derived from that same DEM. Both are in the ...
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1answer
47 views

Does anyone success installed Mask R-CNN IN GRASS GIS?

As title, does anyone success installed Mask R-CNN in GRASS GIS? Also, I found a script for updating GRASS GIS in order to use MASK R-CNN as below: To use environment setting flags like –overwrite, ...
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0answers
23 views

GRASS GIS: r.out.gdal raises an exception and hangs if it's called multiple consecutive times

I'm using a small python routine (grass.script, pygrass) to handle several operations on sentinel2 imagery. I'm calling r.out.gdal inside the script and a very annoying problem occurs: when it is ...
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0answers
32 views

Route optimization with QGIS

I need to optimize the routes of a collection vehicle working with QGIS. To do this I have a network layer and another with the collection points, both of then in a geopackage. What I need is a new ...
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1answer
37 views

How does r.lake in GRASS work? [closed]

I want to create a raster file with only the lake data with the r.lake tool. The data should only cover the lake that is red in the picture. The inputs required for l.lake are: Raster file with ...
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2answers
77 views

Perform the sum between two raster, one of which has a value of “nodata” or “null” in QGIS

I have two raster (raster1 and raster2) from the same area. I would like to make the sum between the two (raster3 = raster1 + raster2) in QGIS, so that the Digital Number (DN) of raster 3 is the sum ...
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1answer
55 views

Is it possible to get the the layer returned by a GRASS tool without saving it to disk in QGIS?

I use some GRASS tools in QGIS Python Console. All tools I use return a dictionary with a key and a value which contains string path, like this: {"output": "file/path"}. There is ...
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0answers
15 views

Process time in spatial join in GRASS

Has anyone determined process times in a question in GRASS? I would like to know how much, on average, it could mean to cross a spatial join in GRASS, with two SQLite bases, of approximately 10 ...
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1answer
37 views

r.damflood in Grass 7

There are 4 required inputs for this addon (r.damflood) in GRASS. elev= elevation raster map (raster file with elevation data) lake= water depth raster map (raster file of only the lake area) ...
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1answer
51 views

What is map file in GRASS GIS addon r.fuzzy.system and how it can be accessed?

I am inexperienced with GRASS GIS and I am trying to reproduce the fuzzy systems manual example. I am failing to load the MAP file, even if I wrote the 'txt' file with the rules and maps name. Here is ...
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0answers
26 views

GRASS ERROR “raster not found” with i.image.mosaic tool in QGIS 3.10.10

I'm trying to mosaic multiple DEM files using the GRASS 7 'i.image.mosaic' function in QGIS 3.10.10, on a Mac. I keep getting the same error code and have not been able to figure it out. Details of ...
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1answer
22 views

v.to.rast doesnt work: Just takes objectID from one area!

my exercise is to rasterize the districs of Baden-Wuertemberg. I do this with the following command: v.to.rast input=bw layer=1 type=point,line,area output=bw_raster use=attr attribute_column=OBJECTID ...
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1answer
38 views

Using GRASS i.segment in Python 3 stand alone script on Windows10

I installed GRASS GIS 7.8.1 on Windows 10 using a OSGeo4W. I would like to use in a stand alone Python 3 script the i.segment GRASS tool. I saw some related questions (e.g., Using GRASS GIS in Python ...
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0answers
11 views

Execute the command r.thin

I have an image that I want to thin, after calling the image on the grass and executing the r.thin command, it was not thinned and the output image is as follows: image original: And output image of ...
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0answers
138 views

Error in GUI startup when launching GRASS GIS 7.8.4

I have just installed the latest version of GRASS GIS(7.8.4) but it doesn't launch. I've tried reinstalling a few times and nothing seems to work. Does anyone know what is wrong? Starting GRASS GIS... ...
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1answer
29 views

Import MATLAB data (.mat) in GRASS

I have a file from MATLAB in (.mat) format. I want to import this in GRASS GIS, but I get the following warning.
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0answers
27 views

Error executing r.drain

I´m trying to do a Least Cost Path with Grass and when I try to use r.drain I can't. It say to me error raster map not found.
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0answers
30 views

Using i.albedo in QGIS

I was wondering if anyone has used the i.albedo processing tool in QGIS? I am looking to do an analysis on a composite image from Landsat 8 and don't really know where to begin. I am using version 3....
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0answers
33 views

Using r.thin in GRASS

I am new to GRASS GIS. I need to run my program with the r.thin command, and I will not get any results as I proceed according to the program. My map is a png image in 2 bits. How do I execute this ...
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0answers
17 views

Which layer creation option (lco) to pick in v.in.dxf?

I'm trying to properly upload a DXF via the GRASS option into QGIS. It is a building structure of LoD2 quality. Unfortunatelly, while the importer runs I always get the error: WARNING: Vector map is ...
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1answer
38 views

Inspect raster value of a pixel to see bits that are on/off in GRASS GIS

I am working with Landsat-8 C1-Level 2 imagery and I need the information that NASA provides in the pixel_qa file. The information about the content of the pixel is given by turning on a certain bit, ...
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0answers
103 views

AMD processor has compatibility with QGIS and Grass GIS?

I would like to ask if the processors AMD are compatible with Q GIS, GRASS GIS as well as Rstudio. Until now I had Intel i5 and I would like to go to AMD Ryzen™ 7
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1answer
16 views

GRASS7.8 setup to work externally in Python

I am following the instructions in https://grasswiki.osgeo.org/wiki/Working_with_GRASS_without_starting_it_explicitly#Python:_GRASS_GIS_7_with_existing_location to setup GRASS 7.8 to work with Python ...
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1answer
77 views

Euclidean distance units for WGS84 files?

I have a lake raster file and I want to calculate the euclidean distance. My raster file is in EPSG 4326 and I use the r.grow.distance from GRASS GIS through QGIS plugins. What are the units from the ...
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0answers
31 views

Calculate PV rooftop potentials in Berlin QGIS 3.16. (OS Windows 10)

I want to analyse PV potentials of roofing in QGIS (v. 3.16). I am experienced in vector data analysis but have barely worked with raster data sets. I therefore have no experience and am asking for ...
2
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0answers
78 views

GRASS tools (v.generalize, v. clean) error with polygons in projected CRS (EPSG:3857/Web Mercator)

I have troubles using several GRASS GIS tools from QGIS 3.16 (win 10) - I encountered the same problem applying v.clean as well as v.generalize tools (I tried Douglas Peuker algorithm). I tried a lot ...
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1answer
24 views

v.to.3d Fails in QGIS

I've been able to use the vector to 3d tool successfully on some contour information before, but it's throwing an error anytime I work with data from New Hampshire's Granit site. In QGIS, the tool is ...
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2answers
44 views

QGIS 3.14 with GRASS 7 error on batch dxf export

I tried to do a batch export of 19 geopackage layers to dxf and got an error I don't understand (I don't speak Python very well). First error of 19 pasted in below from my log, all of them the same. ...
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0answers
38 views

Simplify/generalize vector geometry with side bias

I have contour polygons as vector geometry with attached elevation attributes. Is there a method to simplify vector polygons while preserving topology and elevation bias? By elevation bias I mean that ...

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