There are a wide variety of ways to describe the locations of objects in space. To name a few, there is: WGS84, the well-known Earth-bound system of latitude and longitude; ECEF (“Earth-centered, Earth-fixed”), a Cartesian coordinate system fixed to Earth’s axes; NED (“North, East, Down”), a coordinate system that describes where in compass directions a given object is relative to an observer; or FRD (“Front, Right, Down”), which describes where a given object is relative to the facing direction of an observer. And to make matters worse, points in all of these systems except WGS84 can be expressed in Cartesian coordinates (ie, X, Y, and Z), spherical coordinates (ie, angle to pole, angle on XY plane, and radius), or horizontal coordinates (ie, azimuth, elevation, and distance).

When we write software for systems that have to handle real-world coordinates, the question of what coordinate system those coordinates are in, and how they’re represented, comes up a lot. And getting it wrong in even a single place opens the door to disastrous consequences. To that end, for work, I wrote the now-open-source crate Sguaba (named after the self-navigating boat of the Celtic deity Manannán mac Lir that is navigated solely by the thoughts of its pilot). Sguaba is a Rust crate that strongly types coordinates and vectors with their respective coordinate system, and implements conversions between them.

In this talk, presented at the Rust Amsterdam meetup @ BlockTech, I go into the complexities of spatial math, as well as how we can use the type system to encode those complexities away. Plus, answers to lots of questions!

Sguaba open-source announcement from Helsing: https://blog.helsing.ai/sguaba-hard-to-misuse-rigid-body-transforms-for-engineers-with-other-things-to-worry-about-than-aeaa45af9e0d

Sguaba on GitHub: https://github.com/helsing-ai/sguaba

You can find the slides at https://jon.thesquareplanet.com/slides/sguaba/ (or an export at https://jon.thesquareplanet.com/slides/sguaba/export.pdf).

0:00:00 Introduction
0:01:28 Talk
0:31:40 Q&A

Jon Gjengset

Sguaba is a type-safe spatial math library written in Rust that handles coordinate system transformations for 3D space. The talk covers the complexity of spatial math — including local body frames (FRD, FRU), local tangent planes (NED, ENU), and global reference systems (WGS84, ECEF) — and explains why getting these conversions wrong is easy and costly. Sguaba encodes every coordinate frame as a distinct Rust type, uses the typestate builder pattern to enforce valid construction, and chains quaternion-based rigid body transforms in a way the compiler verifies. Unsafe is used unconventionally to mark places where the caller must assert runtime facts (e.g., a plane's GPS position) that cannot be statically verified, making type-safety violations visible. The library is available on crates.io with extensive documentation and property-based tests.

Sguaba: Type-safe spatial math in Rust