26 votes

Drawing wavy/wiggly lines in QGIS

Short answer: you can get it using a custom SVG. See bottom of this post for one. Long answer: I believe it is better to represent it than to modify the line geometry. Should you want to move an ...
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  • 35k
22 votes
Accepted

Drawing wavy/wiggly lines in QGIS

I propose a solution using PyQGIS. It should work both for Linestring and MultiLineString layers. This solution is based on the creation of semicircular rings, so you need to set a value for the ...
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  • 15.6k
20 votes
Accepted

Showing the bounding box for every coordinate system in QGIS

Yes, QGIS holds this information in an SQLite table. Go the menu layer / data source manager and select Browser then go to where QGIS is installed (like C:\Program Files\QGIS 3.16\) and dig down to ...
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  • 35k
19 votes

Shifting display of overlapping lines in QGIS?

I propose an approach that only recurs to a geometry generator and a custom function. Before starting, I want to underline that I will focus the attention on the explanation of the minimal things to ...
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  • 15.6k
18 votes
Accepted

Styling polygon layer as dissolved with QGIS Geometry generator

You can now do this with the geometry generator in QGIS 2.99/3.0 by using buffer(collect($geometry), 0) in the expression builder. The new collect() aggregate function collects all the feature ...
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  • 7,494
17 votes

Viewing LIDAR data (.las) in QGIS?

QGIS 3.18+ supports point cloud visualisation natively.
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  • 1,083
14 votes

Simple thematic mapping of shapefile using Python?

I came across a number of tutorials dealing with this topic that I wanted to share: So You’d Like To Make a Map Using Python - Stephan Hügel How to Make a US County Thematic Map Using Free Tools - ...
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  • 35.5k
14 votes

Styling polygon layer as dissolved with QGIS Geometry generator

I've tried using the Geometry Generator with no success, and decided on a "Virtual layer" and a SQL query SELECT st_union(geometry) FROM layer_name You need to replace "layer_name"...
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14 votes

Making lines curvy in QGIS

Use Arrows style instead of Simple Line style. For example, these lines with Simple Line style: look like this with Arrow style: You can turn off the arrow heads by setting the head width and ...
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  • 23.2k
12 votes

Setting layer visibility in QGIS Python API?

For QGIS 3, you have to use: QgsProject.instance().layerTreeRoot().findLayer(layer_id).setItemVisibilityChecked(False) or to be safe node = QgsProject.instance().layerTreeRoot().findLayer(layer_id)...
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12 votes

Drawing wavy/wiggly lines in QGIS

Attention! This answer is outdated. Please follow the link here: Custom QGIS linestyle expression function won't work with MultiLineStrings In QGIS 3.10 it's possible to dynamically create zig-...
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  • 3,763
12 votes
Accepted

Making an animation of an evolving digital elevation model

Probably the best tool for this is Paraview. Once you've downloaded and acquired that you'll want to load your images: Use the CSV reader to load them: Below, you can find filters faster by pressing ...
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  • 1,761
11 votes

Showing antenna symbols on the map: point symbols or features (polygons)

If you want to use symbology only, I propose a solution inspired by my answer from a similar question: Creating sector lights in QGIS?. Following a similar approach, and assuming you are working on a ...
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  • 15.6k
11 votes

Producing Space-Time Cube in QGIS

One option to do this would be by modifying your data and visualizing it with the excellent qgis2threejs plugin. The idea is to turn your your time to Z coordinates. I tried it out with two GPX tracks ...
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  • 563
10 votes

Changing marker shape based on a rule or column value in QGIS?

Assuming to start from a point layer having this Attribute Table: you can perform the third step: "Shape of marker denotes if the soil samples were taken in "topsoil" or "other"." by firstly ...
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  • 15.6k
10 votes
Accepted

Permanently viewing vertex of polygons in QGIS

Using the green plus in the symbology tab of your layer properties, add a second symbology. Change that type to border - marker line and the placement of the markers to every vertex.
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  • 13.2k
9 votes
Accepted

Plot tilted map in R

The examples in your link look like the coordinates have been transformed via a shear and a scale matrix. You can easily apply this to the coordinates you get from the usual fortify/join data that ...
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  • 52.9k
9 votes

Assign a specific color to vector layer based on RGB codes in attribute table

In the layer styles panel if you click on simple marker, there is a small box to the right of the fill color combo box - if you click on it you can select edit from the menu and enter the expression ...
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  • 75.5k
9 votes
Accepted

Rule-based symbology in QGIS

On the symbology tab of the properties - Select Rule-based For the filter enter "riparian Veg" = 'Yes' AND NOT "Primary" = 'Riparian vegetation management' capitalization matters - it has to match ...
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  • 5,426
8 votes
Accepted

Visualizing large datasets of polygons with Leaflet

Firstly, check out this post. It may not be exactly what you want though, which is why I did not mark this thread for closure as a duplicate. Secondly, there are a number of tactics you can employ ...
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  • 33.1k
8 votes
Accepted

How to assign colors to specific raster values using R

You can define your own color palette by concatenating two predefined color palettes and your desired gray color as: [red orange yellow palette] + [zero gray color] + [blues palette]. To get zero ...
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  • 3,006
7 votes

Viewing LIDAR data (.las) in QGIS?

Update: As stated in Peter's answer: QGIS 3.18+ supports point cloud visualisation natively. Some documentation for reference: QGIS 3.18 changelog. Installation guide. The crowdfunding initiative. ...
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  • 9,911
7 votes

Using GIS tools for non-geographical problems

Very interesting question! Found a couple more examples and included a brief quote and their citation (quite fun to see how GIS software can be used in completely nongeographical applications): LASER ...
7 votes
Accepted

Showing antenna symbols on the map: point symbols or features (polygons)

A few days ago a new plugin was added to QGIS called Wedge Buffer Processing Algorithm. This looks as if it might be of interest. As the name suggests it's a processing algorithm, so you'll need to ...
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  • 19.8k
7 votes

Plot tilted map in R

Extending on @Spacedman's answer, creating a stacked map like the one shown in the question becomes quite simple. You just need to add another map layer and displace its y axis: e.g. aes(x=x, y=y+5) : ...
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  • 1,138
7 votes

Making lines curvy in QGIS

If you are using QGIS 2.12 or later, you would have "Add circular string" Tool in "Digitizing Toolbar". Or you may want to try "Spline plugin". (LHS) Add circular string tool during digitize, (RHS)...
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  • 29.2k
7 votes

Changing marker shape based on a rule or column value in QGIS?

Another approach is to use nested Rule-based styling for "study name" and "topsoil / other" categorical fields, followed by size assistant for "sample numbers". Starting from Layer Properties | ...
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  • 29.2k
7 votes

Drawing wavy/wiggly lines in QGIS

An expression that solves this was added to QGIS 3.24 (https://github.com/qgis/QGIS/pull/45583). Use this expression in the Geometry Generator: wave($geometry, 15, 3)
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  • 2,029
7 votes
Accepted

Why are buildings shown with a distortion instead of directly from above?

It should depend on the Coordinate Reference System (CRS) you are using for your project. This is one of the very first tasks when working with GIS, so please read here for a gentle introduction to ...
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  • 15.6k

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