Foss4g NL: morning sessions (vector tiles, noise levels, digital twins)¶

(One of my summaries of talks at the 2021 FOSS4G NL one-day conference).

Vector tiles - Edward Mac Gillavry & Frederieke Ridder¶

His talk is about their (webmapper) experiences with vector tiles.

They started with map based story telling. You highlight individual locations, you add textual explanation and perhaps graphs. When moving and rotating between the locations, it can be very nice to have a “2.5D” view. For instance they made a map that showed the buildings in the Netherlands, with the correct height, color-coded by height category.

The advantage of vector tiles here is the speed and ease of animation. And that you can “stretch” the

Another nice example is https://kaart.75jaarvrij.nl , an interactive map of the liberation of the Netherlands in 1944/1945. A date picker allows you to go through time. Military unit locations, food droppings, liberated areas: everything is done vector-based. A big advantage is that you only have to download small amounts of data. Interactiveness

A new project is https://cartiqo.nl, a vector map with various Dutch open datasets. They host it via https://www.maptiler.com/, a Swiss company. Vector tiles give them lots of flexibility with changing the visualisation of the map: color-coding according to different criteria, for instance. If you select a different parameter to highlight on, you just change the visualisation of the already-downloaded geo data instead of downloading the same data as raster images again.

So: speed, flexibility, ease of use!

Geo plus noise - Rob van Loon¶

He works at the RIVM, well-known in the Netherlands for their recent health-related work. But they do a lot more, for instance air quality and environmental noise. Noise can negative effects on your health. Road noise, wind turbines, heavy trains, planes, industrial noise.

Noise: they look at it in three ways: source, transmission and recipient. For recipients there’s the public building data (houses, hospitals). For sources, there are also good datasets: the public road network database, railway maps, etc.

Roads and railways are linear. You also need to look at the kind of traffic, the intensities, the kind of paving material or kind of railway sleepers, etc.

Transmission of the noise: there is a lot to take into account. Are their other buildings in the neighbourhood that can reflect noise? What’s the ground use like? A concrete paving lot transmits sound pretty good, grassland dampens it a bit. Are there woods in-between? How does the height map look? Is there line-of-sight between the source and the recipient?

Lots of calculations. And you need to do it multiple times, as they take into account various frequency bands. Low frequencies behave in a different way to high frequencies regarding distance traveled and way of deflection.

A major end result are contour maps with noise levels for the whole of the Netherlands. Since a while, there’s even a 3D model.

Digital twins - Marko Duiker, Thieu Caris¶

The Dutch province of Zeeland has a lot of use for 3D data. Everything that’s inside the ground (cables and so). The border between

They have an IoT (internet of things) infrastructure based on TTN (The Things Network). One of the IoT users are “multiflexmeters”: open source arduino-based groundwater level meters.

They try to use as much open source as possible. Not everything is possible yet, sadly. But when they can switch, they will.

Digital twin: you try go have as good a digital representation of reality as possible. So that you don’t need to go to some piece of equipment, for instance, when it tells you it needs maintenance: you don’t have to visit it, you can simply trust it.

Digital twin: they way the dunes and the beach change through time. If you present it as 3d, including visualizing differences between the stages, it starts to “live” for you. Interaction is easier and it is easier to work with.

They use “cesium terrain builder + cesium terrain server” to convert 2.5D data to 3D. The cesium stuff is hard to install, but with docker it gets easier (there’ll be a talk about it later). This way they’re able to visualize 3D in a reasonably performant manner.

Reinout van Rees

My name is Reinout van Rees and I program in Python, I live in the Netherlands, I cycle recumbent bikes and I have a model railway.

Weblog feeds

Most of my website content is in my weblog. You can keep up to date by subscribing to the automatic feeds (for instance with Google reader):