h3 VS ctl

It looks like the base Kontur dataset uses H3 resolution 8, and there’s a lookup table here. “400m” seems to refer to the edge length (which averages to 461m).

I can speak to quadtrees, but the primary reason for using this is that you need a geographic "dictionary" (not using the word map to avoid confusion with charts), and you're perhaps already using the H3 hexagonal grid system.

HexSet: is a way of storing a set of H3 cells in a tree, and doing fast (2-20 ns on my 2013 trashcan Mac Pro) membership tests. You must first convert the input data (e.g. GeoJSoN polygon) into H3 cells.

> What an amazing tool that can completely change function names when it converts from C to Go.

How can one read the code of the benchmark, then switch into virulent sarcasm mode without trying to understand the code? And seeing "+1" comments without any effort to understand is also disheartening.

The blog post had a link about the Go helper functions the author used. It lands on https://github.com/akhenakh/goh3/blob/main/h3.go This shows that the `FromGeo()` function used by the Go benchmark is a helper that calls transpiled functions. The benchmark code itself was of course not transpiled, so the sarcasm was unneeded and wrong.

If anyone wants to dig in deeper, the C function `latLngToCell()` calls 2 functions, see https://github.com/uber/h3/blob/master/src/h3lib/lib/h3Index...

Uber just released their library to perform geospatial indexing - https://h3geo.org/. This might be an useful building block for you.

Well, I do like mine better, which is closer to the STL, and for all containers. https://github.com/rurban/ctl/

search for htable or hashtable in thousands of open source projects. only a minority has worse hashtables than this one (clisp, perl5 e.g.).

For better ones I would point to my linked list implementation: https://github.com/rurban/ctl/blob/master/ctl/unordered_set.... (because it has various security policies, nobody else has)

C Container Template Library, Rurban Variant (CTL) - The page for unordered_map reads "Implementation in work still".

There is also the rurban variant variant of CTL which is more complete.

The prototype of CC used this mechanism to provide a generic API for types instantiated via templates (so basically like other container libraries, but with an extendible-_Generic-based API laid over the top of the generated types). This approach has some significant advantages over the approach CC now uses, but I got a bit obsessed with eliminating the need to manually instantiate templates.

But the most common that I know of is this one: https://github.com/tylov/STC. There's also this one mentioned above https://rurban.github.io/ctl/

I'm also working on a proper one, but got sidetracked. https://github.com/rurban/ctl/blob/hmap/ctl/swisstable.h