Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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. ...

-3
votes
0answers
16 views

GRASS GIS Intro at GEOSTAT 2018 - Tutorial is not reproducible in Windows [on hold]

I am trying to follow and complete the tutorial found int the following link for GRASS GIS Intro - Analysing ECA&D climatic data However, I am having a lot of trouble following it because the ...
0
votes
0answers
23 views

Error when importing data source from web using GDAL/OGR in GRASS 7.4.1

I am running the latest bundle of OSGeo4W with GRASS 7.4.1 I am following the tutorial in the following URL: Analysing the ECA&D climatic data, where I am trying to import data from web using ...
0
votes
2answers
33 views

DEM from Vector to Raster in GRASS GIS

I am using GRASS GIS 7.4 and I have a DEM as points in a vector format and want to turn it into a raster. I tried using v.to.rast and v.to.rast3, but the elevation is not one of the attributes so am ...
1
vote
0answers
21 views

Error with QGIS and Grass Tools

I wanted to use the r.viewshed tool in QGIS. Everytime I want to start the tool there is a error (german): Dieser Algorithmus kann nicht ausgeführt werden run :-( GRASS GIS 7 ist anscheinend nicht ...
2
votes
1answer
36 views

Can't call GRASS commands with Python on QGIS 2.18

I'm trying to run a grass command (v.split.length) using the processing library in pygis. The script is as follows: import processing layer = r'path\to\shp.shp' extent = QgsVectorLayer( layer, '', '...
0
votes
1answer
25 views

Install GRASS GIS extension r.pi including r.pi.prox and implement the Addon in QGIS

I would like to install the GRASS GIS addon r.pi within QGIS, I only have access to basic GRASS commands I installed QGIS using the osgeo4w-setup-x86_64.exe advanced installation using the http://...
2
votes
0answers
38 views

Convert polygons to lines ignoring redundant vertices in QGIS

Provided the following Polygons layer with 6 polygons (see image below), I would like to calculate each line's segment's angle (amongst other things), so I should convert those six polygons into lines,...
1
vote
1answer
43 views

Extract a line segment out of a polyline on the basis of numeric values (distances) defined as attributes [QGIS]?

I have a set of points (red in the picture) in a shapefile containing an ID as well as two numeric values representing distances in Meters for each point. After creating polylines for each point via ...
0
votes
0answers
19 views

v.surf.idw raster file conversion into a vector with same colours style

Is it possible to convert from raster to vector the raster file resulting from grass interpolation algorithm "v.surf.idw" coloured with the quantile method and maintain such colours in the vector file ...
0
votes
0answers
57 views

How to automate topology check/fix in QGIS?

Short version: I have a layer with 19483 features with plenty of topological errors and I would like to fix/review them as many as possible in an automated way but don't know how to do it. ...
0
votes
1answer
27 views

GRASS: Can v.buffer use geodesic distance like r.buffer does?

Question: In GRASS GIS, can v.buffer use geodesic distance like r.buffer does? If v.buffer can't use geodesic distance, is there a way to do vector geodesic buffering (ideally in GRASS, but I can ...
0
votes
0answers
12 views

Grass(v.net.visibility): Performs visibility graph construction with only one point

Problem I would like to get the visibility of one point in regard to a polygon layer. E.g. which island can I see from the beach. What I found It's possible to get a visibility graph via Grass v....
0
votes
2answers
32 views

Issue with exporting GRASS visibility graph to shapefile

I am rerunning code in GRASS that has worked in the past (about six months ago) and am now having problems. In the GUI, I have created a new mapset and imported the 'SimplifedCoastline' file to the ...
0
votes
1answer
27 views

How can I interact with PyGrass after a script is launched?

From Grass GUI 7.4.1, I launch a .py script (File > launch a script) that builds maps. How can I interact with the maps viewer, selecting the coordinates of some features, giving them as a new input ...
0
votes
1answer
25 views

Error creating Terrain in HEC-RAS

I am struggling to produce a terrian file with RAS Mapper. I have a .tif file produced from a .asc raster elevation and when I tried to add a New Terrain Model as described in the documentation I get ...
0
votes
1answer
20 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
vote
2answers
33 views

v.surf.bspline and Interpolation(cublic spline) persistent errors in QGIS 3.2 & 3.3

I'm new to QGIS and as such I'm pretty hesitant to post anything, but I cannot for the life of me figure out why two raster creation techniques are not working. For the v.surf.bspline GRASS algorithm:...
1
vote
2answers
23 views

Translate manual operations to GRASS commands

I am new in GRASS GIS and i wanted to know how i could translate GRASS manual operations to GRASS commands in the console. I imported a raster and i was able to see the command r.import input=XXXXX\...
1
vote
0answers
25 views

QGIS Processing v.net.distance Error

I am hoping that someone can point me in the right direction. I am wanting to calculate the distances from a point to each point in another layer along a road network using v.net.distance. I have done ...
0
votes
1answer
34 views

Loading ADF file from National Elevation Dataset into GRASS with Python?

I'm trying to load data from the National Elevation Dataset into GRASS/Python, using this Python script (outside of GRASS): # Imports import os import grass_session from grass.script import setup as ...
0
votes
1answer
14 views

Entry point not found Error initiating GRASS GIS from Python

I cannot run any GRASS tools from within Python 2.7.15. While the GRASS environment, grass.script etc. are loading correctly and I can run basic checks like gscript.read_command('g.gisenv') gscript....
1
vote
1answer
13 views

Georeferencing CAD drawing and setting ground control points in GRASS?

I'm fairly new to QGIS and Grass GIS, and learning the interface. I have a CAD drawing that has no coordinate system assigned and needs to be georeferenced to NAD83 HARN Northern Colorado (feet). I'...
1
vote
1answer
57 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
vote
3answers
123 views

Convert dwg (CAD) to shp in any open source GIS software?

I would like to do what's needed in a GIS (GRASS, QGIS, etc) alone, no other converters-only. The process is to read the dwg files that would be located in a folder and read them as shp and perform ...
2
votes
1answer
83 views

Create New Mapset (GRASS) in QGIS 3.2

How do i create a new mapset from QGIS 3.2 for GRASS? I can´t find the Plugin GRASS in manage and install plugins...
0
votes
2answers
63 views

where is the v.transects algorithm in qgis?

I am interested in using the v.transects GRASS command. I am however not yet proficient with using GRASS or python in QGIS environment so I would rather do it the old-fashioned way (i.e using the GUI)....
1
vote
1answer
78 views

Dividing a buffer into segments based on path and distance

I have a buffer layer which I generated from a polyline layer and then dissolved. I then rasterized the dissolved buffer layer, thinned it based on this link and generated a new (more approximate) ...
2
votes
1answer
43 views

What s a good beginners default setting for grass?

I would like to define some business areas as a regular pattern within a polygon (e.g. I draw a polygon on a map and then create regular tiles of a certain length in it, while the tiles at the border ...
0
votes
0answers
50 views

3D view of a thickness raster

I have a thickness raster and sediment core data (collected within the raster area in excel format). Is there any option to create a 3D view of a thickness raster incorporating with core length?
0
votes
1answer
13 views

Band Ratios in GRASS

I am trying to execute in mapcalc a simple band ratio exercise. I have set new map as "Band 12" and entered this equation into mapcalc: Band12== Band1@MApset/Band2@Mapset I hit "Run" but I keep ...
1
vote
0answers
16 views

V.Net.Allpairs not working

I have two layers: (1) point layer (city centroids) and (2) OSM road shapefile layer. I want to know the distance to take from one city to another. I want to output a matrix like this: from\to ...
0
votes
1answer
21 views

Why doesn't wx graphical modeler Grass gis 7 work properly in Spanish?

I am working with the wx graphical modeler in grass gis 7. When I try to use a variable call "archivo" in spanish, wich is "file" in english, it does not work. The variable dont let me choose a file. ...
0
votes
1answer
49 views

Merging two processes in QGIS3 to one?

Is there any way to merge several processes in QGIS3 into one process? Or is there a way to look at the source code of different processes under QGIS3 and combine them under one function? I am ...
2
votes
3answers
48 views

Tagging and adding attributes on OSM road layer in QGIS

I have downloaded an OSM road layer and I want to add attributes and tag specific line segments. I have another layer of centroids from a polygon layer of cities which will be the basis for my nodes. ...
0
votes
0answers
15 views

GRASS: v.overlay with multipolygon outputs - or v.dissolve on multiple attributes?

I am using GRASS 7.3 to create overlays (intersections) of two multipolygon layers. I want the output map to contain a unique (single) multipolygon for every overlap of two unique multipolygons from ...
2
votes
0answers
45 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 ...
0
votes
0answers
23 views

How to setup 52°North WPS with GRASS backend under Windows and Linux?

I followed tutorials TutorialBackendGRASSWin and TutorialBackendWpsGRASSLinux to setup 52°North WPS with GRASS backend under Windows and Linux (CentOS7), but result of GetCapabilities request does not ...
0
votes
0answers
14 views

Deleting multiple columns in vector attribute table selecting by wildcards in GRASS

I need to delete a series of columns of a vector attribute table inside GRASS before starting further processing. I know I can use v.db.dropcolumn map=vector@PERMANENT columns=col1,col2,col3 But if ...
1
vote
0answers
17 views

Semi-automatic classification with GRASS modules

I'm applying between QGIS and GRASS to apply a semi-automatic classification of aerial photos. In practice I would like to use the combination of the grass modules in the processing of QGIS; i.cluster ...
0
votes
0answers
22 views

Grass Transparent Heatmap

I made a heatmap raster layer in GRASS 7.0.3 and am trying to change the color table so that the lower end is transparent and the higher end is red. Right now if I put the heatmap raster as the top ...
1
vote
0answers
59 views

v.rectify don't work properly from processing toolbox in QGIS 3.2

I would like to use the tool "v.rectify" from GRASS in my plugin, but when I call it, it continues to say that "ERROR: Required parameter 'output' not set", although this parameter is set. I think ...
0
votes
2answers
59 views

Use GRASS-GIS features in a python script

I'm writing a python script in which I want to import some grass functions. To test the script I used a test command like r.null, but the code returns an error before that. The procedure I'm using is ...
2
votes
0answers
98 views

remove/fill gaps inside polygon qgis

I have created a polygon from grass gis and found small triangle like structure inside the polygon (sometimes at the edge to outside), that I want to remove/fill. I tried with geometry check to fix ...
2
votes
3answers
119 views

Nearest distance from point to pixel in QGIS?

I have 1) a point layer and 2) a binary raster file (1 and 0). I need to estimate the Euclidean distance from each point to the nearest "1" pixel. I know there is a tool in ArcGIS but I only have ...
1
vote
0answers
30 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/...
0
votes
1answer
35 views

Copying Grass data from one location to another in Grass GIS

I have created several Grass locations with single mapsets while processing a series of satellite imageries at different stages of my analysis. Now I need to copy some preprocessed rasters and ...
0
votes
0answers
31 views

v.to.3d can't seem to find polygons

I am trying to use the v.to.3d algorithm from GRASS in QGIS, but whenever I try to run it, it seems to not be able to find the polygons that I am inputting. This is the result of the operation: ...
1
vote
0answers
34 views

r.stream.basin in qgis

I am trying to generate subbasin with provided multiple outlets points by using r.stream.basin. I have install r.stream.basin addon in grass but it does not appear in qgis. Is there any ways to use ...
0
votes
1answer
38 views

Creating a GRASS mapset from a bash script

This is a follow up to a previous question on the creation of GRASS locations from a bash script. Having successfully created a location, I would now like to create a new mapset within this location. ...
1
vote
1answer
36 views

Creating a GRASS location from a bash script

I would like to have a GRASS script that creates a new location of its own, instead of using an existing location. This facilitates the usage of the script by other users. Going through the guide on ...