Questions tagged [qgis-3]

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

798 questions with no upvoted or accepted answers
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10
votes
0answers
119 views

Is there a way to create quadrilaterals buffers around polygons in QGIS?

For a little map project of mine, I need to create quadrilaterals around a polygon feature based on the bisected angles of the vertices of that feature. Here is an example: Is it possible to automate ...
8
votes
0answers
649 views

How to use ATOM FEED Data in QGIS 3.6.1?

I would like to know how I can work with ATOM FEED Data in QGIS. In ealier QGIS versions this worked with the Plugin "INSPIRE ATOM Client", but this Plugin doesn't work in the current version. An ...
8
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0answers
311 views

Point cluster symbology for different categories without overlapping symbols

I'm trying to visualize crimes based on if the crime happened during day or night time. I've tried using the point displacement tool but I'm not satisfied with the results because the readability for ...
7
votes
0answers
167 views

Using Layer Parameter variables in Field Calculator within QGIS Model?

If I define a Vector Layer as an input parameter to a QGIS model, then the parameter name is exposed as a variable in a Field Calculator within the model, however I am unable to use this variable as I ...
6
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0answers
256 views

QGIS projects in PostgreSQL (pyQGIS - saving proj to DB)

I'm currently working on some code to automate the creation of a QGIS project from tables in a PostgreSQL DB. For info I'm working in QGIS 3.4. I'm almost there, but I'm stuck on one thing How do I ...
6
votes
0answers
800 views

Join attributes by location very slow on QGIS 3.0

"Join attributes by location" is very slow on QGIS 3.0. I have tried it with a CSV file and also with a shapefile (point layer) and a grid (made of polygons). On QGIS3.0 it takes about 3 hours to ...
5
votes
0answers
47 views

QGIS 3 Display negative values bar diagrams

Suppose I have a dataset with an id (for each geographic entities) and 2 numeric fields NUM1 and NUM2. These numeric fields have positive and negative values. When I use bar diagrams, only theses ...
5
votes
0answers
1k views

QGIS 3.4 and loading raster from multiple variable NetCDF file

Using QGIS version 3.4.4 when loading a NetCDF file out.nc which contains multiple variables on a fresh Ubuntu 18.04 install I encounter the following error: CRITICAL Invalid Layer : Raster layer ...
5
votes
0answers
193 views

Setting grid in QGIS that automatically adjust its intervals?

I am setting a template for multiple maps in QGIS 3 Layout and i was wondering if there is a way of automatically adjusting the grid's interval as a function of the scale of the map? I did a bit of ...
5
votes
1answer
1k views

QGIS GRASS Processing Not Working on MacOS?

Recently upgraded to QGIS3 (3.0.2) for MacOS (High Sierra) and encountered GRASS (7.2.2) issues. Tried adding a custom variable and now when running GRASS algorithms (e.g. r.reclass) I get the ...
4
votes
0answers
66 views

Showing labels as they will be printed/exported in my print layout?

I set up a print layout for a map I want to print in QGIS. Some of my layers have labels on them. When I zoom in and out in the screen, without changing anything else on the print layout, some labels ...
4
votes
0answers
49 views

Measure loading times of QGIS projects

For QGIS there is already a method to measure loading times of plugins ( qgis.utils.plugin_times): How to tell which QGIS plugins are slow to load? Is there something similar to measure loading ...
4
votes
0answers
141 views

“Driver not loaded Driver not loaded” when trying to connect to MSSQL database in QGIS 3.8 on MacOS

When trying to create a new MSSQL Connection, I get an error saying: Error opening connection: Driver not loaded Driver not loaded. I have tried both QGIS 3.8.0 and the newest pre-compiled QGIS 3.8.1 ...
4
votes
0answers
76 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 ...
4
votes
0answers
1k views

Invalid geometry error when running Vector Intersection tool in QGIS 3

I am reworking an exercise that runs fine in QGIS 2.14 and 2.18 but have encountered an error in QGIS 3.2. I am using Windows 8. I am using the Alaska training data and adding the majrivers and trees ...
4
votes
0answers
93 views

QGIS rule based symbology for rasters in Atlas?

I'm making species distribution maps and have got the Atlas working perfectly using a polygon layer to show the quarter degree grid cells for species observation records. I have ~ 250 species. Problem ...
4
votes
0answers
226 views

Unable to connect to postgres server in Database Manager

I try to connect to my postgres server, hence I got this failure And following error: 2018-04-26T18:02:05 WARNING Traceback (most recent call last): File "C:/OSGEO4~1/apps/qgis/./python/...
4
votes
0answers
223 views

Connectors do not appear automatically in easy custom labelling

I'm using the easy custom labelling plugin in QGIS 3. When I move a label away from its associated polygon a connector does not automatically appear as in QGIS 2.18. How do I get connectors to appear ...
4
votes
1answer
270 views

PostGIS table shows twice in QGIS Browser panel

I've observed for a while that for many (but not all) of my tables, QGIS 3 (2.99) shows the same table name twice in the Browser Panel on the left, when I expand my PostGIS data source. The first ...
4
votes
1answer
372 views

QGIS 3.6 picture in ui form (Qt5 Designer)

I'm facing trouble with display a picture in a ui form based on a field (path). With the autogenerate form it works but when I try with a personalized form I cannot see the picture. I tried with a ...
3
votes
0answers
36 views

Delete “children” feature, if “father” feature is deleted, inheritance

I am developing a dimensioning tool, and I would like that the "son" feature been deleted, when the father is deleteted, (on the fly). How can I do this? It can be done via application or PyQGIS. ...
3
votes
0answers
33 views

Evenly spaced labels for polyline layers

I'm using QGIS 3.8 and am attempting to label roadway segments (OSM) of varying length. By checking the "Merge connected lines" box and hiding features below a certain size, I can generally limit the ...
3
votes
0answers
42 views

QGIS C++ 3D Map Scene

I want to use QGIS with c++ api like ArcGis runtime sdk. I tried to use Qgs3DMapScene class like QgsAbstract3DEngine *m_window3DEngine; Qgs3DMapSettings *m_mapSettings = new Qgs3DMapSettings; ...
3
votes
0answers
77 views

Creating convex hull by expression by aggregating points

I would like to recieve the centroid of a convex hull of a group of points in a layer, grouped by its name. This needs to be done by expressions, available in QGIS 3.4. E.g. I have this list of points:...
3
votes
0answers
123 views

QGIS 3.10.x WMS Problem

Using Ubuntu 18.04. I have problems loading UK Environment Agency WMS layers. This first arose when I installed QGIS 3.10 and persists in QGIS 3.10.1. It appears that when QGIS makes a WMS request ...
3
votes
0answers
36 views

Delineating zones based on number of polygons that are in overlay

I am working in urbanism and I have a number of polygons that represent perimeters where certain "programs of revaluation" have been carried out. However, as can be seen on the map below, over time, ...
3
votes
0answers
25 views

Deleting input vector or raster being used in QGIS 3 modeler

As it is explained in the title I am writing a script to process this task. The script is already written but I need it to be triggered when the inputs are not needed anymore. In other words : I need ...
3
votes
0answers
45 views

How to reimport a QGIS 3.10 Vector-GeoPDF, generated from layout manager, so that all items not belonging to layers are hidden?

I'm very impressed with the new GeoPDF export capabilities of QGIS 3.10 (Windows 10). Now we can create Vector-GeoPDFs with layers included! With the help of GDALs "Geospatial PDF" file format ...
3
votes
0answers
50 views

Different distance when using “Measure Line” tool and manually with scale in QGIS 3

Using QGIS's "Measure Line" tool I get a distance of 1.22km between two points. But if I use the scale indicated at the bottom of the screen, 1:50000, and measure with a ruler, the distance is 2.5km (...
3
votes
0answers
34 views

Find distance between multiple discrete sets of points QGIS3.8

No similar question seems to relate to my issue but I desperately need help with calculating distances. I have a CSV with the residential postcode of 200 000 patients. For each patient, I also have ...
3
votes
0answers
35 views

PyQGIS Layout - Change Image Source QGIS 3

Looking for a solution to loop through existing layouts in a QGIS 3.6 document and change a source of an image. The image is the same in each of the layouts. What I have is: from qgis.core import ...
3
votes
0answers
44 views

“Bring All to Front” is missing in QGIS 3

I am using QGIS 3.4 and 3.10 and a plugin's window ends up hiding behind the canvas. In QGIS 2.10 I had the option "Bring All to Front" to bring all windows to front. Is there an alternative for it ...
3
votes
0answers
43 views

Joining attributes from points to polygon

I am working with two shapefile, polygons and points. These shapefiles do not overlap and have different attribute values. The point layer contains data that I want to join to the beginning and end ...
3
votes
0answers
64 views

Error while running batch processing in QGIS 3

I have built a straightforward model in the Graphical Modeller in QGIS 3.4 to select features by expression and then save the selected features to a new shapefile. It works when running singly but ...
3
votes
1answer
66 views

Distance between points along line

How do I determine the distance between points to the neighbor point that connected via the line(road)? In QGIS 3.8.3 I have tried v.distance and v.net.distance but they do not help. The line(roads) ...
3
votes
0answers
33 views

Changing Map Tip popup direction dynamically

Is there a way to dynamically (or semi-automatic) change direction of a popup? Default direction is 'right-down', which in some cases, where hovered feature is at the bottom of a canvas, Map Tip is ...
3
votes
0answers
40 views

QGIS 3 3D Marker

In the 3D view I add 3d.obj files as Marker.works very well. Is it possible to add different 3D markers on different layers or categories. When I use 2 different layers with different obj files 3D ...
3
votes
0answers
53 views

Offset Expressions Dynamic QGIS - Unique non-repeating Numbers

I am trying to create a layer style that shows line features that share the same geometry, an exploded view for line Features. What I have done so far via the Offset expressions in QGIS 3.6 ("...
3
votes
0answers
81 views

No Vector Menu Available QGIS 3.4

I've installed QGIS 3.4 on my Mac. I don't have any vector or processing menu. In the "plugins" menu under settings, I have the following: "The settings on this tab are only applicable for Python ...
3
votes
0answers
96 views

Errors opening Geospatial PDF in QGIS 3.8.3

I'm a complete QGIS newbie so bear with me if I'm missing something obvious... I'm unable to open GeoPDF's that I've downloaded from USGS's The National Map (TNM) site. This is the error that I get ...
3
votes
0answers
61 views

Testing nodes connectivity

I'm working on a shapefile of Brussels (QGIS 3). This shapefile contains all the streets in Brussels, see below. With the attribute table, I have an "X" and "Y" position for each line (debut and end),...
3
votes
0answers
106 views

Running Standalone PyQGIS Script with Multiprocessing?

Is it possible to run a standalone PyQGIS script using multiprocessing for better performance? I'm creating 1,800 rendered map images and would like to run it across 4 processes to speed it up. If I ...
3
votes
1answer
167 views

QGIS cannot import SciPy (QGIS 3.6 Noosa, Ubuntu 18.04, EnMapBox plugin)

I had been struggling to get QGIS installed because (currently) the ubuntugis repo seems to not be working well (couldn’t load Python at all). I got around that problem by installing QGIS using ...
3
votes
0answers
84 views

QGIS 3.4.6 Cannot create fields in new shapefiles

Running 3.4.6 on Windows 10. Until today I have had no problems creating new shapefiles and fields. Now when I create a new shapefile everything in the new dialog box works as usual when I create ...
3
votes
0answers
43 views

QGIS 3 embedded forms - zoom or pan to child features

I have two tables and a relation defined on them via an 'in-between-table' (many-to-many relationship) like this: This gives me nice embedded forms like shown below: What I would like to achieve is ...
3
votes
0answers
58 views

Setting input layers as PostGIS tables when building a model?

I am trying to build a QGIS 3.8 model where the same inputs are used each time and only the clipping layer extent changes. I can do this using shapefiles and editing the script to use the same input ...
3
votes
0answers
56 views

Disable map zooming with QGIS 3.5 +

I am trying to disable zooming with the mouse wheel for QGIS 3.8. Past versions have had an option to under Settings/Preferences -> Map tools, but this appears to have moved with the newer versions. I ...
3
votes
0answers
54 views

Using shared database authentication settings for organization environment?

My company is willing to share common QGIS3 configuration parameters between its users (ie. proxy configuration, WFS/WMS connections definitions, database connection definitions). For doing this, ...
3
votes
0answers
52 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
votes
0answers
48 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 ...

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