Frustum Culling [testing help wanted]

In computer game development there is a fairly common optimisation called frustum culling.

In the example above, the players camera is on the right. When the player moves their camera around the game engine stops rendering all the objects outside of the view of the camera. Since the player can't see behind them, there's no point rendering all those extra bits of the game.

So what does this have to do with SondeHub? Well SondeHub tracker is a fork of the HabHub tracker. HabHub was all about tracking amateur balloons. At anyone time there might of been 10 or so balloons on the HabHub tracker. It was feasible for the website to handle rendering all those balloons. SondeHub on the other hand is handling ~200 radiosondes each peak.

We've been delivering and displaying all that data. Every radiosonde telemetry frame has been sent the browser and the browser has tried to plot each and everyone.

What's the impact of this:

• Infrastructure costs: the number of servers required to send all that data
• Data transfer costs: the cost send to that data to you
• Client / browser performance

So what is SondeHub changing?

First off, data ingestion, archiving, and our APIs haven't and won't be changing. If you are using any of our APIs they will continue to work like usual.

We are effectively trying to implement the same style of frustum culling that games do but for SondeHub. We don't want to download and render any of the data that isn't visible on the map.

What we have implemented is in the tracker webpage. When this feature is released the web interface is going to change a little. The first noticeable change is that high zoom levels ( like where you can see most of the world ) you'll notice a little warning on the map.

The data presented when at this zoom level is what we call the slow feed. It'll show the rough location of all the radiosondes in the air right now plus any new ones that are detected. Once you zoom in, the locations of the radiosondes visible on the map will begin to update.

You'll also notice that we no longer display the trails, and predictions by default. Don't worry, they are still there! Click on the radiosonde or selecting from the menu will display the path and predictions like normal.

Hiding the trails/predictions results in a lot less work for the web browser, making the page quicker to use. It is also required as the client might not have the data required due to the culling.

You can get an idea of how many radiosondes your browser is currently tracking by looking at the debugging information in the bottom right hand corner of the map.

With these changes we hope to reduce our hosting bill and improve the client side experience.

Why didn't we do this sooner?

It's actually a fairly difficult problem to solve and we wanted to make sure we solved it in a way that didn't impact usability of our users. We also need to make sure the changes don't just move costs from one part of the platform to the other.

We believe we've struck a good balance between optimisation and usability.

Help wanted!

Before we roll out these changes we want to make sure they work reliably and that our Patreons aren't impacted by any usability concerns. For that we ask that you help test. To do so use our testing site:

https://testing.v2.sondehub.org/

If you find any bugs that impact you please report them to GitHub Issues  or otherwise add a comment in this post.