Giles van Gruisen explains the underlying concepts of Felt, and more generally web maps, a tad downplaying the complexity involved:

Don’t worry if these concepts are a bit confusing at first, this stuff is tricky!

That’s one way to put it, considering what is involved in making zooming and panning performant interactions:

Specifically, when the user starts any gesture that might affect the viewport position, we immediately take note of the original viewport state. Then, as we calculate the new viewport position, we can easily derive a transformation that we can use to translate and scale existing element geometries to their new positions and sizes. So, rather than continuously projecting every last coordinate pair on every single frame, we calculate a single “viewport transformation” that can be applied to all of them.

To take it a step further, we don’t actually need to apply that transformation to every single element individually, but rather to a single parent layer that contains all of the shapes as children. This results in a single compositing layer being translated and scaled, and makes for highly efficient zoom and pan gestures. Finally, when the user stops their gesture, we do actually recalculate the projected position of each coordinate pair, and in a single frame swap the old geometries for the new, and remove the temporary transformation.

Whenever I read an article like this, I feel grateful for anyone building and maintaining map libraries and applications. This is complicated stuff, and seeing how easy it is to put a map on the Web these days makes you realise how much thought and work goes into these solutions.

Ed Freyfogle on The OpenCage Blog:

I’m forced to clarify this because we are getting more and more support requests from people who have been mislead by YouTube tutorials that a simple python script can be used to determine the location of any phone simply by entering the phone number.

Thought I’d share this to help spread the word.

Chris Holmes wrote an excellent summary of the Cloud-Native Geospatial Outreach Event, which took place in April and gathered people working with new cloud-native geo-data formats and APIs, like COG, Zarr, STAC, or COPC. Chris highlights selected talks to get you started with the formats, how organisations adopt them, and tutorials going deeper into technical details.

Once you’re finished watching Chris’ recommendations, you can dive into the humongous 90-video playlist of all of the event’s talks, which should keep you busy for a couple of days.

Flatgeobuf is a relatively new binary format to encode geographic vector data. Unlike vector tiles, Flatgeobuf is a lossless encoding format, which is streamable and enables random feature access.

Horace Williams wrote a comprehensive overview of what goes into a Flatgeobuf file and how it is structured internally.