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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16 views

Is there any interoperability between GRASS and PCRaster?

After having looked at PCraster river network it seems that GRASS makes better work. But PCRaster is the best for building models. So is it really possible to use python-grass scripts for delineation ...
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46 views

Error when using r.reclass in QGIS - GRASS

I am trying to run the r.reclass tool but I got the following error: Traceback (most recent call last): File "C:/OSGEO4~1/apps/qgis/./python/plugins\processing\algs\grass7\Grass7Algorithm.py",...
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22 views

v.overlay with empty layer [closed]

I'm writing a Grass Python Script (using GRASS GIS 7.6.1) for a project for university. Sadly, I never learned Python, so it's a bit tricky but so far I got everything done I wanted to. The Script ...
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50 views

Mapshaper simplify equivalent in GRASS

I was shown the simplify function of https://mapshaper.org/, which removes unnecessary vertices in polygons. Now I'm looking for a similar function in QGIS and found GRASS generalisation. Since I'm ...
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24 views

Grass plugin not working

I am trying to work with GRASS in QGIS 3.10.1. I went to "Manage and Install Plugins", searched for it, and checked the box for GRASS 7. That brought up an error message that says "Grass was not found ...
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16 views

RUSLE3d parameter and validation

I am a graduate student in remote sensing studying soil erosion. I'm very new to GRASS GIS software. I don't want to use North Carolina data. I also read the software homepage. Do you have any ...
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16 views

Importing multiple Esri ASC files into GRASS, then exporting to Unreal Engine

I'm trying to import LiDAR scan data from Defra in the UK into Grass. The data appears to be in Esri ASC format, in multiple separate files. As this is the first time I've used GRASS I'm struggling ...
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1answer
14 views

Creating reclass-rules-textfile within Simple Python Editor of GRASS GIS

We are writing a script with the simple Python editor (GRASS GIS). We try to set the rules for a reclass command within the script (without creating a txt.file manually). Is it possible to set the ...
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35 views

GRASS GIS code - equations used in the modules

How can I view the equations used in the GRASS GIS modules? I found the code here: 1) URL: https://trac.osgeo.org/…/re…/raster/r.watershed/front/main.c; 2) URL: https://github.com/OSGeo/grass/tree/...
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gtk.css:2:33: Failed to import in Grass GIS

When first I run GRASS GIS 7.6.0, there is an error message : (gis_set.py:4772): Gtk-WARNING **: 16:05:43.648: Theme parsing error: gtk.css:2:33: Failed to import: Error opening file /home/mega/....
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2answers
27 views

Densify and smooth out categorical raster with diagonal neighbors

I'm classifying vegetation types in QGIS (3.10). I have a pretty coarse raster that I want to smooth out. The standard approach seems to be to polygonize and then apply various smoothing algorithms (e....
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13 views

GRASS report list of parcel values

Is there a way to get a report of the values of every land parcel on a raster map layer? In the same way r.report can be used to find how large the parcels are.
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GRASS r.statistics method=average for non-integer maps

I need use the functionality of r.statistics using the average method. I have one map with cell clumps for a base layer and another containing various non-integer cell values for a cover layer. ...
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1answer
28 views

Measuring compactness using GRASS

Is there a way to find the compactness (ratio of perimeter to area) of various groups of contiguous cells using GRASS functions? If you imagine I want to find the compactness of the three land ...
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2answers
33 views

GRASS r.mapcalc to replace null values

Is there a way to use r.mapcalc to replace null with 0? I tried if(isnull(map1), 0) but that produces a map that is entirely 0. I need only cells containing null to be altered!
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2answers
18 views

Multiply cell values during r.mapcalc in GRASS

I'm doing some sieve mapping in GRASS. I have several map layers containing various values representing site suitability ranks. I need to use r.mapcalc to add these maps together for example map1 + ...
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2answers
39 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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1answer
61 views

How to simulate tsunamis and other natural disasters? [closed]

How do you go about simulating natural disasters like tsunamis? We're mainly looking for a place that might have more too. Currently, we're trying out GrassGIS's Tsunami tool, but it seems to have ...
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1answer
29 views

GRASS GIS Addon Installation Windows 10 Problem

I know there are some very similar questions regarding this topic: GRASS GIS addon "extension not found"; could the problem be with the GRASS Addons server? but so far nobody has found a ...
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1answer
36 views

Unable to find the GRASS module i.ortho.rectify on QGIS

I am using QGIS 3.4.2-Madeira. It has GRASS 7 as a core plugin. In QGIS, when I open Processing Toolbox, I can see the GRASS option but under the imagery sub-menu, I cannot find the i.ortho.rectify ...
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19 views

Error with i.segment.stats in GRASS

I have this error on GRASS. I am working on windows and was using the command i.segment.sats Calculating statistics for raster maps... Traceback (most recent call last): File "C:\Users\Ouati\...
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1answer
39 views

How does r.fill.dir work?

I'm trying to calculate subglacial sink volume by using the rgrass7 package to utilize GRASS functions in R. However, the sinks found by the function seem to be very small: When I run the similar ...
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1answer
28 views

PyQGIS: error message “Cannot run algorithm wrong parameters for method” when trying to use GRASS tool

For my QGIS plugin, I'm trying to use the GRASS Tool r.neighbor. I wrote the following code which should run the tool and return the result as a raster object. def focalStatistics(self): ...
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0answers
41 views

Why graphical models from GRASS 7.6 don't work in GRASS 7.8?

I was working in some graphical model with grass and developed in GRASS GIS 7.6. Now I did an update with osgeo instaler from GRASS 7.6 to GRASS 7.8. When I try to run a graphical modeler nothing ...
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1answer
53 views

Geomorphons for a geomoron: running grass command in external python

I'm a fairly competent Linux and Python user and looking to utilize the GrassGIS geomorphon function (https://grass.osgeo.org/grass78/manuals/r.geomorphon.html) to parse out subaqueous features. I've ...
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1answer
29 views

Focal statistics using GRASS GIS r.mapcalc

I have a workflow in ArcGIS that I'm trying to convert to GRASS GIS. Part of this workflow involves using Raster Calculator to execute a conditional statement. If the conditional statement is true, a ...
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1answer
22 views

GRASS GIS r.in.gdal, import multiple band ncdf

I am trying to import a ncdf file with 20000 bands (time steps of precipitation) to grass gis using r.in.gdal. My problem is that i dont need all the bands, only a portion of it, e.g : band 1 to band ...
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1answer
68 views

Increasing spatial resolution of Landsat MSS and TM images? [closed]

I am trying to do a timeseries analysis of morphological change in the coastal zone using images from Landsat 1 MSS, Landsat 5 TM, Landsat 7 EMT+ and Landsat 8 OLI. My problem is that although I can ...
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0answers
11 views

Adding WMS layer to map with ps.map

The GRASS GUI provides a feature to add WMS layers to the Map Display. I would like to do the same in a map produced with ps.map. The goal is to use the WMS simply as a map background, without having ...
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1answer
50 views

R.Series in QGIS 3.14.3 GRASS 7.6.1 returning no data value outputs only [closed]

I'm using QGIS 3.14.3 with GRASS 7.6.1 and trying to add together the values for 3 raster layers using r.series as I'm told this handles no data values better than raster calculator. Please see log ...
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0answers
39 views

GRASS 7 problem

I am working with QGIS 3.8.3. I want to split my lines into intersections and for this, I tried to use the command v.clean in GRASS - Processing Toolbox. However, an error msg appears: "This ...
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1answer
51 views

GRASS v.clean gives weird results

I have the following yellow line layer and I would expect the v.clean tool to split my lines at each intersection. Running the tool gives me the red lines. The settings are all on default. Why is that,...
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1answer
81 views

Line of Sight between sets of two points each

So I have a list of points with their longitude and latitude (Lon_A, Lat_A and Lon_B, Lat_B). I also have a DEM layer from the SRTM for the relevant location. I need to check if line of sight exists ...
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1answer
37 views

Reading vector-dataset with rgrass7

I have read in some vector data with rgrass7 and produced some output Layers using Grass in R. Now I wanted to import one of the created layers back into R and convert it into an sf- object. When I ...
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32 views

Find GRASS GIS path on Ubuntu

I want to use algorithms from GRASS GIS in R. One essential step is already providing some serious problems. I managed in some way to install GRASS on Ubuntu 18.04, but now I need to provide the path ...
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1answer
27 views

Summing thousands of rasters in GRASS GIS (after reach r.series limit)

I am using GRASS GIS 7.6 and want to sum 30.000 small rasters from a total viewshed calculation. I tried the following approach: 1-> r.list to get a list of the names of the rasters. 2 -> r.series (...
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0answers
43 views

Unable to Merge Multiple .DXF Files and Output .DXF Using Merge Vector Layers

I'm using QGIS 3.8.3 with GRASS 7.6.1 to merge multiple .dxf files into a single .dxf file. When I attempt to use the Merge Vector Layers via Vector>Data Management tools>Merge Vector Layers, I get ...
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2answers
80 views

How to rotate rasters with GDAL, QGIS or GRASS GIS

I need to rotate raster files from the TRMM Multisatellite Precipitation monthly product 3B43. For some unknown reason, this data comes rotated 90 degrees clockwise, meaning that the y coordinate is ...
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63 views

Raster map not found error with r.fill.dir

I am new the GIS world and I am having trouble with generating depressionless DEM from lidar elevation data. I am using GRASS 7.6.1 and QGIS 3.4.12. I have used r.fill.dir successfully on a ...
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1answer
64 views

rgrass7: “no stars import yet”

I would like to read a raster layer from GRASS 7.8 into R 3.6.1 (on Ubuntu 18.04). Whenever I use the reasRAST method I get a cryptic message that simply says "no stars import yet" [sic]. The console ...
4
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1answer
128 views

Processing toolbox not working in QGIS 3.4.13

The processing toolbox stopped working in the previous QGIS 3 ltr version I had installed. Now installed 3.4.13 but processing toolbox still not working. I've tried changing the GRASS path without ...
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14 views

Adding raster Data from Geodatabase to QGIS [duplicate]

I have raster data in a geodatabase and want to open them with QGIS. When I navigate with QGIS to the Geodatabase I get to this window. Unfortunately, I can't open These atx and GDBTABLX files and I ...
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0answers
26 views

Using Shapely polygons with GRASS GIS in Python

Would anyone be able to provide an example of how to work with Shapely objects in GRASS modules? Preferably how to convert Shapely polygon to GRASS format in order to use various tools within GRASS.
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34 views

System couldn't find given path while running v.split

I'm trying to run the Grass Tool v.split and get the following error message: the grayed outline in German translate to "The System couldn't find the given path" The .exe-files of the grass Tools ...
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1answer
26 views

GRASS GIS module dialog not starting

my module dialogs are not appearing in GRASS 78 (for 76 it is working) e.g. I want to change the colour of a vectorlayer and click on the properties button, but no module dialog will open.
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0answers
16 views

GRASS 7.6 Add-on install issue

I've been trying to install add-ons wihtout success. I keep getting an error message: ****IOError: [Errno socket error] [Errno 10060]**** Une tentative de connexion a échoué car le parti ...
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1answer
42 views

Upgrade to GRASS 7.8 - “NameError: name '_' is not defined”

I have recently updated to GRASS 7.8 and I am now getting this error any time I try to execute a command: leni@eecdd4f59c3b:/app$ grass78 Default locale not found, using UTF-8 Default locale settings ...
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1answer
103 views

QGIS v3.10 GRASS plugin on MacOS for hydrology

Installed QGIS 3.4 and then 3.10, both gave errors "Grass was not found in /usr/local/opt/osgeo-grass/grass-base" In both cases the directory /usr/local/opt/osgeo-grass/ did not actually exist. I ...
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0answers
48 views

Error on QGIS r.reclass for Mac and Windows

I am currently trying to use r.reclass from QGIS on Mac computer. However, if I run r.reclass it keeps getting error message: Traceback (most recent call last): File "C:/PROGRA~1/QGIS3~1.8/apps/...
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1answer
27 views

Set TIFF's location creating raster with GRASS

I'm trying to create a raster with GRASS using the command r.in.gdal input="landsat-image.tiff" output="landsat-image.output" but I am getting this error: Locação PROJ_INFO é: name: NAD27(76) / MTM ...