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Questions tagged [qgis-3]

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

0
votes
0answers
7 views

QGIS 3.4.4 Crash on vertex editor

I've just installed QGIS 3.4.4. Each time I edit any layer, as soon as I select the vertex editor (single shapefile) I receive the 'unknown exception error'. The error then occurs with ANY edit in any ...
2
votes
2answers
153 views

Is there a maximum number of features that QGIS can save into a shapefile?

I have a very large .gdb that I want to reduce to my study area. Unfortunately, the study area is still quite big. I could select features that intersected my study area but when I tried Export > ...
0
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0answers
10 views

Problem with repo qgis.org/debian “does not have a Release file”

When I include deb https://qgis.org/debian/ buster main deb-src https:://qgis.org/debian/ buster main in my /etc/apt/sources.list file, and run sudo apt uptdate I get: E: The repository 'https://...
2
votes
2answers
86 views

Black theme (“Night Mapping”) doesn't load

At work we are using QGIS 3. When we were using QGIS 2 I enjoyed working with the black theme, called Night Mapping, for healthy eyes, etc. With QGIS 3, when I click on the menu of the themes and pick ...
2
votes
0answers
30 views

QGIS 3.44 heatmap to contour file

I am trying to convert a point file, currently displayed into a contour file. The methods that I have tried, all expect a raster file as an input, but my source file is a vector file points, i.e. I ...
2
votes
1answer
36 views

Customizing QGIS interface?

I'm trying to customize QGIS 3.4 interface to allow data display only. None of the default QGIS geospatial data editing functionalities should be exposed to the end user. Also, the users should not be ...
3
votes
0answers
36 views

How to test the geometry type from a list of layers and then join it with PyQGIS 3

Summarizing my problem, I'm a beginner and I'm developing a plugin that will be able to do several spatial joins. For this, it will have to separate the spatial from the non-spatial layers and do the ...
2
votes
0answers
16 views

Why are labels and looks different between print layout and map canvas at same scale?

I know that some of my items uses map unit as size unit, others mm and labels points. But the map canvas where I do all my changes should still look exactly the same in print layout if I'm using the ...
1
vote
3answers
66 views

How to fill unconnected areas in polygon with the same attribute

I am trying to fill in the gaps with the same attribute. These arrowed areas belong to a city called 'Westbank', but the thing is, these areas are unconnected, how can I make a polygon out of areas ...
2
votes
3answers
67 views

QGIS 3.4 : Add points to exact locations?

I would like to add several coordinates at specific British National Grid Easting and Northing values. I know this can be done by bringing in a .csv, but I want to know is there a way to manually ...
1
vote
0answers
45 views

Difference between DEM raster in QGIS 2.18 and 3.4.4 [duplicate]

I came across a really strange problem. Untill today i always worked in QGIS 2.18. Now i wanted to upgraded to 3.4.4 ( it was already downloaded but hadn't used it yet) When opening my QGIS ...
2
votes
0answers
24 views
+100

Filter layerlist in snapping dock of QGIS3 to show only layers selected in the layer-dock (TOC)

I would like to filter the layerlist in the "Snapping and Digitizing Options"-Dock so that only layers are shown which are selected in the TOC of the QGIS-Layer-Dock. At the moment I use a workaround ...
0
votes
0answers
16 views

Plugin Validity in Migration QGIS 2.18.19 to QGIS 3.4.4 [on hold]

I am fairly new to the QGIS platform, as I have worked on it only for the last year. I need to check if the following plug-ins will be available in the newest LTR release: -Georeferencer GDAL (I see ...
1
vote
1answer
34 views

Stuck on how to list loaded layers in QGIS 3 via Python

I've stuck on a issue about getting a list of loaded layers. I've two layers loaded, one spatial (point, line or area) and another one non spatial (postgresql table). I've tried this code but it lists ...
1
vote
2answers
34 views

Reclassifying by layer in QGIS?

I am trying to reclassify a DEM by using the new Reclassify by layer tool in QGIS3. I am using the following input table: However, as shown in below screenshot of the tool, the Minimum class value ...
1
vote
1answer
19 views

How to get file path from vector layer object in QGIS 3.x processing framework?

Using the QGIS 3.x processing framework, given a vector layer as an input parameter: (from the default script template) def initAlgorithm(self, config=None): self.addParameter( ...
2
votes
1answer
31 views

Importing QGIS3 processing tools in standalone script

Inspired by this question, but for QGIS 3 (and therefore Python 3), I would like to use the QGIS processing algorithms in a standalone Python script without a GUI, with a standard installation of ...
3
votes
1answer
21 views

Is it possible to default an output directory for R Scripts in QGIS 3.4.4?

I am currently running R Scripts through the Processing R Provider plugin on QGIS 3.4.4. I was wondering if it is possible to to set a default file path for your vector output that is the same as ...
5
votes
2answers
95 views

Dynamic copyright or layer credit in QGIS 3.4?

Is it possible to add a layer credit to the bottom right corner of the map and print composer in QGIS 3.4? This fuctionality existed in 2.8, as seen here. I can't find this option in the layer ...
0
votes
0answers
19 views

Is it possible to prompt messages and see progress when running R Script in QGIS 3.4.4? [on hold]

I have an R Script which I am implementing in QGIS 3.4.4 with the Processing R Provider plugin. I would like to now if it is possible to view progress in the GUI whilst running this script and also ...
2
votes
0answers
45 views

QGIS 3 - Wrong legend for datadefined size points layer

I am trying to generate a proportional symbol symbology using data defined symbol size in a QGIS 3 python plugin. Here is the working code : # Symbol creation symbolLayer = ...
2
votes
0answers
47 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 ...
4
votes
1answer
95 views

PyQGIS - QgsColorRamp Shader, Overwrite discrete values?

I'm shading a raster layer using a QgsColorRampShader, using discrete values. Basically, I want to make the value '255' a black color because it is a null value. Here is the step-by-step through my ...
3
votes
0answers
53 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 ...
4
votes
0answers
80 views
+50

Looking for common PyQGIS functions for QGIS 3

I would like to rewrite some of my QGIS plugins to use more common functions used by all of my plugins. There exist some older functions (GIS2) like https://github.com/NathanW2/parfait https://...
2
votes
0answers
33 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"...
1
vote
1answer
26 views

QGIS3 How to export shapefile symbology to scale?

I'm looking how to export in QGIS3 a vector layer with a determined scale. It was straightforward in QGIS2 when I was exporting to a shapefile I had the option symbology scale but it disapear in QGIS3 ...
0
votes
0answers
18 views

QGIS 3.4 startup error: Could not load plugin 'svir'

I use QGIS 3.4 on Mojave, and when after updating to 3.4.4 I began to get an error when starting the program. I am not a programmer and I do not know how to use python or how QGIS and python connect. ...
1
vote
1answer
28 views

QGIS 3 - QSettings().value(r“[…]”)[0:2] error - 'NoneType' object is not subscriptable

I'm trying to find a solution to launch a plugin from outside the QGIS console I've succeeded to call the plugin from the python console in the QGIS software but I'm now trying to do it outside of ...
1
vote
1answer
45 views

XYZ tiles in QGIS 3

When I 1st started with QGIS 3.4.4 I added google maps/ satellite/ relief and they worked for 2 days but now I can't see any form of mapping through the XYZ tiles. I have reinstalled, I have deleted ...
2
votes
0answers
17 views

QGIS turn right click — “Toggle Editing” off

In QGIS3, Interface customization I have turned off the mEditMenu but when a user right clicks on a dateset they still see "Toggle Editing". Is it possible to remove this? and also any keyboard ...
2
votes
2answers
37 views

PyQGIS - Managing print layouts

I'm struggling to understand how to manage print layouts using python for QGIS. For example, I am starting with Zero exisiting print layouts in my layout manager. I create a new print layout and add a ...
2
votes
2answers
32 views

QGS 3.4 many-to-many relations in Forms

On QGIS Attribute Forms, I want to display related Features which are connected via a many-to-many relationship table: Tables / QGIS Layers: Feature a: a_id, geometry, some more attributes Feature ...
1
vote
1answer
25 views

Run pyQGIS algorithm on selected features in layer

I try to run algorithms on layers but only on selected features with QgsProcessingFeatureSourceDefinition in a loop and then write the result with QgsVectorFileWriter : layer1 = QgsVectorLayer(path1, ...
4
votes
1answer
39 views

Is it safe to delete .qgd files in QGIS 3?

I am managing some of my QGIS 3 map files in a git repository. With QGIS 2, the map files (.qgs) are text files, which can be easily handled by git; QGIS3 introduces an additional binary file (.qgd) ...
2
votes
1answer
58 views

Finding the major axis of a polygon (the outline of a sinkhole or doline)

I am using QGIS to do a morphometric analysis of dolines (sinkholes). The dolines have different shapes from circular to elliptical and I need to calculate the major axis of the polygon that ...
1
vote
0answers
18 views

Specific QGIS file will not open and “QGIS quit unexpectedly” screen pops up

This problem has occurred for me several times for different files and I can't figure out what the cause is. I will be working on a QGIS file for several weeks and then all of a sudden one day I can ...
-1
votes
0answers
21 views

QGIS 3.4.4 Fails to mask a Raster

When I use to create a cliped/masked raster from an original one according to the Raster Calculator procedure, it fails. I wrote my intensity images on a .Geotif file using GDAL in Python. I can ...
1
vote
0answers
32 views

QGIS 3 bold Layer names?

In QGIS 2 the Option for bold Layernames was here: Go Settings->Options->Canvas & Legend and set 'Bold group names' to true and 'Bold layer names' to false. This link helps provide context. ...
0
votes
1answer
21 views

Manually edit shapefile coordinates (polygon) QGIS 3

In the QGIS2.18 version I was used to see the point editor table when I would be in editing mode and have clicked a point. A list would appear, with all the points in the selected polygon and their x ...
1
vote
1answer
26 views

QGis 3.4 Categorized Symbology: Overlapping objects

I have a point layer with categorized symbology One object is a big point and one is a smaller one. How do I change which one is displayed in front of the other one?
0
votes
0answers
49 views

Python script randomly crashes QGIS

I'm trying to run a processing script in QGIS 3.4. It doesn't complete because it seems that step 3 is not generated. A few seconds later (after I got the error), QGIS completely crashes (I get the ...
1
vote
0answers
20 views

QGIS extract average attribute value from layer based on vector

Say I have one layer below with the blue, red, and yellow polygons in the image below. Each of these values has a different value for attribute A. I have a second layer, which denoted by the bold box ...
0
votes
0answers
18 views

Making QGIS model that iteratively creates several constant grids at once?

I'm looking to calculate the volume of a virtual reservoir from a DEM. I would use a constant grid (SAGA) to represent the ceiling, and I want to see the change in volume for each 1 metre interval. So ...
0
votes
1answer
20 views

Wrong/Different values from $area and Group Stats

As mentioned in other questions there seems to be a problem with $area when OTF is enabled. In QGIS3 it can not be disabled My project hast EPSG 31255, some layers area 31255 some have different crs....
1
vote
0answers
22 views

Eventfilter on MapCanvas

I'm trying to capture MouseClick events on the QgsMapCanvas. The goal is to intercept the right mouse button and display a custom context menu. If the right mouse button is pressed with a modifier key ...
0
votes
0answers
26 views

Deprecation warning when importing Processing in pyQGIS 3

I use QGIS 3.4 with Python 3.7 and I have a warning message when importing Processing like this : import processing from processing.core.Processing import Processing Here is the message : Using or ...
0
votes
1answer
50 views

Numeric Scalebar round

The numeric scalebar in the map composer shows too detailed information on the output. Moving the Map canvas changes the scale depending on the moved distance on the map. We use EPSG 4258 (ETRS89) ...
2
votes
2answers
37 views

PyQGIS Raster Band Stats - Access pixel values of raster layer

I am trying to access individual pixel values in a raster layer I'm working with. I can use QgsRasterBandStats to get some information about the raster layer with the following code: layer = iface....
0
votes
0answers
24 views

Create raster in QGIS which is the sum of attribute values from point layer within given radius

I would like to create a raster with a specified grid size, where each pixel represents the sum of an attribute value from a point layer with many features at a given radius. I am using QGIS 3.4.4. ...