In his talk titled QGIS 3D: current state and future at FOSS4G 2019, Martin Dobias, CTO of Lutra Consulting talked about the new features in QGIS 3D. He also shared a list of features that can be added to QGIS 3D to make 3D rendering in QGIS more powerful.
Free and Open Source Software for Geospatial (FOSS4G) 2019 was a five-day event that happened from Aug 26-30 at Bucharest. FOSS4G is a conference where geospatial professionals, students, professors come together to discuss about free and open-source software for geospatial storage, processing, and visualization.
This article explores the new features in QGIS 3D native rendering support. If you are embarking on your QGIS journey, check out our book Learn QGIS – Fourth Edition by Andrew Cutts and Anita Graser.
In this book, you will explore QGIS user interface, load your data, edit, and then create data. QGIS often surprises new users with its mapping capabilities; you will discover how easily you can style and create your first map. But that’s not all! In the final part of the book, you’ll learn about spatial analysis, powerful tools in QGIS, and conclude by looking at Python processing options.
3D visualization in QGIS
QGIS 3D native rendering support was introduced in QGIS 3. Prior to that, developers had to rely on third-party tools like NVIZ from GRASS GIS, GVIZ, Globe plugin, Qgis2threejs plugin, and more. Though these worked, “the integration was never great with the rest of QGIS,” remarks Dobias. In 2017, the QGIS grand proposal was accepted to start the initial work on QGIS 3D. A year later, QGIS 3 was announced with an interactive, fully integrated interface for you to work in 3D.
QGIS 3 has a separate interface dedicated to 3D data visualization called 3D map view, which you can access from the View context menu. After you select this option, a new window will open that you can dock to the main panel. In the new window you will see all the layers that are visible in the main map view and rendered digital elevation and vector data in 3D.
With native QGIS 3D support you can render raster, vector, and mesh layers. It also provides various methods for visualizing and styling the 3D data depending on the data or geometry type. Here are some of the features that Dobias talked about:
Starting with QGIS 3, you have three ways to render points:
- Basic symbols: You can use symbols such as spheres, cylinders, boxes, or cubes, apply a color, and apply a few transformations.
- 3D models loaded from a file: You can use the Open Asset Import Library (Assimp) to load the 3D models. This library allows you to import and export a wide-range of 3D model file formats including Collada, Wavefront, and more. After loading the model you can do tweaks like changing the color. However, there are currently limitations like “you can only change the color of the whole model and not the individual components,” Dobias mentioned.
- Billboard rendering: This feature was contributed by Ismail Sunni as a part of the Google Summer of Code (GSoC) 2019 project, QGIS 3D Improvement. The billboard support, which was released in QGIS 3.10, will allow you to render points as a billboard in 3D map view.
For line rendering, you have two options:
- Simple lines: In this approach, you define the width of a line in pixels and it does not change when you zoom-in or zoom-out. This technique preserves Z coordinates.
- Buffered lines: In this approach, you define the line width in map units. So, as soon as you start zooming in the line will appear zoomed out. Buffered rendering ignores z-coordinates.
For polygon rendering, you have four different options:
- Planar 3D entity: QGIS 3 provides a method to draw polygon geometries as planar polygons.
- Extrusion: Extrusion is a way to create 3D symbology from 2D features by stretching it vertically. QGIS now supports extruding a planar polygon to make it look like a box. You can specify a constant height or you can write an expression that determines it.
- Polyhedral surfaces or PolygonZ: QGIS 3 has a provision for creating polyhedral surfaces. Polyhedron is simply a three-dimensional solid which consists of a collection of polygons, usually joined at their edges.
- Triangular mesh or MultiPatch: It is similar to polyhedral surfaces, the only difference is that it consists of individual triangles.
3D map tools
- Navigation: You can use mouse and keyboard to navigate the map. Now, with the latest QGIS release you can also perform navigation using on-screen controls. Dobias said, “This is good for beginners when they are not completely sure about other means of moving the map.”
- Identify tool: With this tool, you can interact with the map canvas and get information on features in a pop-up window. It works exactly like its 2D counterpart, the only difference being it will be on a 3D entity.
- Measurement tool: This tool was also built as part of the GSoC project. This will enable you to measure real distances between given points.
Other 3D capabilities
Print layout support
QGIS already had support to save the 3D map view as an image file, but for print layouts you needed to perform multiple steps. You had to first save 3D scene images and then embed them within print layouts. Also, the resolution of the saved images was limited to the size of the 3D window. To simplify the use of 3D scenes for printing and allow high resolution scene exports, QGIS 3 supports a new type of layout item that is capable of high resolution exports of 3D map scenes.
Camera animation support
With the QGIS 3D support, now users can define keyframes on a timeline with camera positions and view directions for various points in time. The 3D engine will interpolate camera parameters between keyframes to create animations. These resulting animations can then be played within the 3D view or exported frame-by-frame to a series of images.
Configuration of lights
By default, the 3D view has a single white light placed above the centre of the 3D scene. Now, users can set up light source position, color, and intensity and even define multiple lights for some interesting effects.
Rule-based 3D rendering
Previously, it was only possible to define one 3D renderer per layer meaning all features appear the same. QGIS 3 features rule-based rendering for 3D to make it much easier to apply more complex styling in 3D without having to duplicate vector layers and apply filters.
There are many other 3D capabilities that you can explore including terrain shading, better camera control, and more.
Where you can find data for 3D maps
Dobias shared a few great 3D city models that are free to use including CityGML and CityJSON. To easily load CityJSON datasets in QGIS you can use the CityJSON Loader plugin. OpenStreetMap (OSM) is another project that provides buildings data. You can also use the Google dataset search. Just type CityGML in a search box and find the data you need.
QGIS 3D capabilities to expect in the future
Dobias further talked about the future plans for QGIS 3D. Currently, the team is working on improving support for larger 3D scenes and also make them load faster. For the far future, Dobias shared a wishlist of features that can be implemented in QGIS to make its 3D support much more powerful:
- Enhancing the 3D rendering performance
- More rendering techniques like shadows, transparency
- New materials to show textured objects
- More styles for vector layers such as lines and 3D pipes
- More data types such as point cloud and 3D rasters
- Formats support like 3D tiles, Arc SceneLayer
- Animation of data in scenes
- Profile tool
- Blender export
- Rendering of point cloud
You just read about some of the latest features in QGIS 3 for 3D rendering. If you are new to QGIS and want to grasp its fundamentals, check out our book Learn QGIS – Fourth Edition by Anita Graser and Andrew Cutts.
In this book, you will explore various ways to load data into QGIS, understand how to style data and present it in a map, and create maps and explore ways to expand them. You will get acquainted with the new processing toolbox in QGIS 3.4, manipulate your geospatial data and gain quality insights, and work with QGIS 3.4 in 3D.