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Questions tagged [qgis-3]

for questions specific to the 3.x series of QGIS.

784 questions with no upvoted or accepted answers
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48 views

Pyqgis: Added raster layers do not show up

I have a list ("datList") with names of raster layers which I want to add. When I add raster layers in the python console everything works fine: for da in datListe: layerDir = "C:/[path]/" + da ...
3
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0answers
47 views

How to create a path distance matrix?

I have a point layer with multiple points and a layer with the starting point (fire station). In the end, I want to create a contour file with distances. But in such a way that the approximate ...
3
votes
2answers
124 views

Symbol in layers panel not visible

I have a layer with symbology that includes geometry generators. It would appear that because of these the symbol is not visible in the layers panel. Is there a way to show the up most symbol (green ...
3
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0answers
31 views

Calculating direction of polygon using other features? (QGIS)

In QGIS 2 or 3 I have some DEM rasters, on top of that vector layers with plots and buildings + pin (blue one) with coordinates of building. How to calculate position of garden? Is it n, ne, e, se, s,...
3
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0answers
100 views

How to import QGIS layer definition files without losing value relation settings?

QGIS allows groups of layers to be saved as a 'layer definition file'. Where one layer in that group references another - using a 'value relation' widget on its attribute form - these setting are ...
3
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0answers
97 views

How to create equidistant points along lines (network)?

I am trying to create points at every X meters along a set of lines that represent a network. As suggested in QChainage doesn't place points evenly along dissolved lines I managed to this ...
3
votes
1answer
87 views

Data source not found when opening .qgs file

I am using QGIS 3.6.1 with the new geopackage (.gpkg) format. When some of my co-workers open my .qgs-file, QGIS (same version as mine) does to not find the data source for most of the layers. ...
3
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0answers
24 views

Record distance moved and new lat/long in attribute table after snapping points to line

I am using QGIS 3.6. I have a dataset of fish locations (points) that I snapped to a river (line). I would like to add the distance each point moved to the attributes table, as well as the new lat/...
3
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0answers
130 views

QGIS union (one vector layer): side location conflict?

I occurred an error when using "union" tool (only one layer) in QGIS. I have a series of vector files, yet only one vector file fails to union with the error information. The error is: GEOS ...
3
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0answers
293 views

Deleting vector layer from Geopackage using PyQGIS?

Programmatically I have added the vector layers to an existing Geo Package in QGIS 3.2 using python. Similarly, I would like to delete a layer from the existing Geo package using python code. But ...
3
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0answers
125 views

GDAL processing output to memory in Pyqgis

How do I save GDAL processing output rasters to a temporary layer? Using 'memory:' for vector processes works fine, but I couldn't get it to work for GDAL processes. output_rast = self....
3
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0answers
43 views

How to select and move below vertex - Vertex Tool (QGIS 3.6)

I have a path (tracks) generated by points, which I snapped before to a grid (so there is some vertex at the way back that are overlayed), that at some point overlay each other. When you select in the ...
3
votes
1answer
96 views

Joining attributes by location error when finding polygons within district boundaries?

I am using QGIS 3.5. I have a large shapefile (760 MB) with 1800 polygons representing different bird species ranges (download link) I have a second shapefile with polygons of district boundaries (...
3
votes
1answer
101 views

PYQGIS 3 Using the ouptut from GRASS v.distance algorithm

I have a script which is trying to run v.distance on two existing shape files, buildings.shp which containing some polygons and singleasn.shp which contains a single point. This will be run from the ...
3
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0answers
76 views

Finding path between points on limited road network

I am struggling to find a path between health facilities in Madagascar. I think that because the road network (from OpenStreetMap) is limited, the functions in QGIS, such as v.net.distance and ...
3
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0answers
101 views

Automatisation of isochrone map creation in QGIS 3

I need to measure the area of isochrones for a big number of points, for different time thresholds and for different means of transport. I've been using the plugin isochrones in OSM tools with QGIS 3....
3
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0answers
281 views

Extract derived data fields from Shapefiles

I've uploaded shapefiles with professionally supplied survey data into QGIS and it all plots fine, then when I export the attributes table into Excel I see that the XYZ values are all zeros. I know ...
3
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0answers
105 views

Creating equidistant sampling points in polygon in QGIS 3.6.0?

I have figured out how to add random points inside polygon boundaries. Although this works well, nevertheless I need a few different things to happen for my application. What I would like to do is ...
3
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0answers
559 views

CadTools plugin functionality in QGIS 3 beyond Advanced Digitising Panel?

I've recently migrated to QGIS 3.6.0, and I've realised that the wonderful CadTools plugin is not compatible with QGIS 3. I tried to use the Advanced Digitising Panel, but it's cumbersome and not ...
3
votes
1answer
79 views

Programmatically styling layer after output is returned from QGIS 3 processing script?

Hi this may be more of a python question rather than qgis processing script question. I've managed to successfully get the output that I want from my processing script, but I wish to take one step ...
3
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0answers
126 views

Extract water areas from aerial photogrammetry DEM in QGIS

We are working with peatland restoration sites providing aerial photogrammetry of the restoration progress. We want to differentiate between areas water and bare peat which can look very similar in ...
3
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0answers
81 views

Transforming points in CSV to linestring / polyline in QGIS

I have "BeginLat", "BeginLon", "EndLat" and "EndLon" as under in a CSV-file I am trying to import it as a line string but I cant. I tried to import using 'Create a Layer from a Delimited Text File', ...
3
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0answers
109 views

Line perpendicular to the maximum axis of an irregular polygon (sinkholes) QGIS 3

I am performing a morphometric analysis of dolines using QGIS 3. The analysis consists of determining the longest axis (the union of the two most distant points of the polygon) and the shortest axis ...
3
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0answers
260 views

pyqgis - geometry generator - line pattern fill

I'm trying to make a line pattern fill in QGis using the geometry generator and a python function. The code is inspired from this answer : Save line geometry as points geometry in QGIS (pyqgis) from ...
3
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0answers
105 views

Using related layers/tables in background?

I have postgresql/postgis database setup with one to many relationship. I can successfully set it up in QGIS but i would like to keep related tables hidden from Layers Panel to keep the project "clean"...
3
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0answers
71 views

QGIS Server Adding a virtual layer

All my layers in the qgs-project-file are working fine as WMS-layers, but I only can't provide the virtual layer. The virtual layer is an ODBC-Connection of an Access-Database which contains one ...
3
votes
1answer
145 views

Orfeo mshift segmentation asks for condition

I'm trying to run a segmentation using the mean shift. I leave all the parameters as default, but when I run it, it says "Wrong or missing parameter value: Condition". Condition is not a parameter for ...
3
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0answers
70 views

QGIS 3 processing script is recognized as a model

I refer to the QGIS 3 (QGIS 3.4.4-1, 64Bit standalone installer) processing script shown below. If I copy the script, do Create New Script... from the processing toolbox, paste it to the empty script ...
3
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0answers
294 views

QGIS 3.4 Processing Python Scripts folder default configuration is lost

I have lost the default configuration of the 'Processing Python Scripts folder' on QGIS 3.4 and in consecuence some Python processing scripts and plugins cannot work properly because they cannot find ...
3
votes
0answers
471 views

Clip raster by mask layer not working in QGIS 3.4.2?

I've been successfully using QGIS 2.18.21 to "clip raster by mask layer" and then run v.rast.stats. However recently v.rast.stats has stopped working in QGIS 2.18.1. The log does not show an error, it ...
3
votes
0answers
69 views

How to render features that are just outside the map canvas extent in QGIS 3.4?

I am trying to generate a cloudy mask, following the recipe in "Qgis Map Design 2nd ed. Edition". For the most part, I have it working. But when panning around, the mask changes. And I think that ...
3
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0answers
584 views

PyQGIS Layout export

I have some problems with PyQGIS while generating a layout. Here is a minimal (non-)working example in which I first load some layers with their styles. Then I would like to export them using a ...
3
votes
1answer
419 views

Vector Fields as Input Variable in Field Calculator

I’m working with QGIS 3.2 Bonn and I try to build a workflow in the graphic modeler. The model aims to build variable buffers depending on values from two attribute fields of an input vector layer. ...
3
votes
0answers
555 views

OTB-QGIS plugin does not appear in QGIS 3.2 after manual installation

I have followed this instruction to connect the qgis-otb-plugin manually. But after completing all the steps, OTB does not show under Settings > Options > Providers. I cloned the qgis-otb-plugin ...
3
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0answers
244 views

pyinstaller package of pyqgis 3 standalone program failed import qgis.core

I have a working standalone pyqgis program with mapping ability, it was in python 2.7 and qgis 2.x library. I used pyinstaller to package it up. Now I have migrated this application to python 3.6 and ...
3
votes
1answer
444 views

Backup QGIS (3.2.1) layer to independent PostGIS table?

I'd like to make multiple, progressive backup copies of QGIS (3.2.1) layers that are stored in PostGIS tables. I've tried multiple routes to export them as files on disk, but they all seem to destroy ...
3
votes
0answers
210 views

QGIS 3.0.3 (and 3.2.0) crashes on start. Ubuntu 16.04, conda environment

I am trying to QGIS in a conda environment, python 3.6.5, conda 4.5.8, Ubuntu 16.04 Xenial. It crashes upon start-up without even loading all the way. I have tried both QGIS 3.0.3 and 3.2.0 (3.2.0 is ...
3
votes
0answers
258 views

“gdal:cliprasterbymasklayer” not clipping to polygons in QGIS3

I'm working on a plugin for QGIS3, and trying to clip a raster layer using a vector mask layer containing many polygons. I've been able to successfully do this using "Clip raster by mask layer" ...
3
votes
0answers
327 views

Wrong length values on QGIS 3.0.3 and 3.2

While using QGIS 3.x today I noticed that length values were not calculated and measured correctly on EPSG:32611. Calculating and measuring the same data on QGIS 2.18 latest LTR and 2.2 on EPSG:32611 ...
3
votes
0answers
579 views

Removing duplicate labels in QGIS3

I have a layer (streets) where I want to remove duplicate labels and then set a display interval for the labels. This is relatively easy in ArcMap because removing duplicates is based on the label ...
3
votes
0answers
64 views

How to split lines with defined split number by user in pyqgis?

Actually my question is on header. I want to split (or explode whatever you say) every line in my lineshape layer. For every line, I must define the split number and it should split them with equal ...
3
votes
0answers
194 views

PyQGIS 3.0: cannot make it work under Windows

I've just tried to install QGIS 3.0 package in my Anaconda (Win7x64, Python 3.6 x64). I wanted to use QGIS widgets in my PyQt application. Alas, QGIS works incorrectly: at first, when I just tried to ...
3
votes
0answers
216 views

Changing point cluster symbol color by expression (color ramp with manual intervals)

I am working on cluster map (QGIS 3.0). My map display both "not clustered" markers with color attribute based on manual brackets ( [1-1.9); [2-4.9]; (5+ ) and clustered markers (red color). What I ...
3
votes
0answers
859 views

Difficulty using ordinary kriging in QGIS 3

I have a shapefile with 65 data points. Each data point has a value for NO2 pollution. I would like to use kriging to create a grid of NO2 pollution values for the whole area. I have tried using ...
3
votes
0answers
60 views

Where does qgis store calculated field from field calculator?

When adding a (computed) field for a PostGIS table, where is the new field stored? I thought it would be with the original table, but it does not seem to be the case for QGIS 3.0.1/3.0.2 (Ubuntu 16.0....
3
votes
0answers
63 views

QGIS 3 Plugin Cancel Edits is crashing plugin

I was using, this method in QGIS2. self.iface.actionCancelEdits().trigger() This method was used, on canceling the edits in the iface. But this method is crashing my plugin on QGIS 3. What is the ...
3
votes
0answers
475 views

Oracle connections fail in QGIS 3.0 DB Manager

Oracle connections are working OK in the Browser panel, the Data Source Manager, and the Python console, but any attempt to open a connection in the DB Manager is failing. The database is a fresh 12.1....
3
votes
0answers
329 views

Using QGIS 3 Plugin Builder on a Mac

Now that I have QGIS 3 running nicely on my Mac. I am having another go at building some plugins. I have installed the plugin builder plugin and run it without problems and it has generated a source ...
3
votes
0answers
121 views

How to transfer QGIS configurations to latest version?

I have QGIS 2.18.11 on my machine. There are saved wms, wfs and DB connections. After installing QGIS 3.0 I can see saved wms connections but no DB connection is listed in 3.0. Collegue's problem is ...
3
votes
0answers
299 views

Install a specific nightly version of QGIS 3 on Ubuntu?

Is it possible to install the nightly version of QGIS 3 for a specific date (code version)? I'm working with QGIS 3 development version which recently has some issues with projections and crashes. I ...