roaring
h3
| roaring | h3 | |
|---|---|---|
| 5 | 21 | |
| 2,349 | 4,593 | |
| 0.9% | 0.7% | |
| 7.6 | 7.2 | |
| 14 days ago | 5 days ago | |
| Go | C | |
| Apache License 2.0 | Apache License 2.0 |
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For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
roaring
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I have some questions about defining a series of bits in Golang
For (3), and if you’re interested in checking if specific bits are set or not, take a look at https://github.com/bits-and-blooms/bitset and https://github.com/RoaringBitmap/roaring.
- Bitmasks - how and why to use?
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Skipfilter
Each topic has a roaring bitmap. Each bit corresponds to a subscriber in the skip list. For each topic, head and tail cursors are also maintained to ensure that newly added subscriptions are always tested and deleted subscriptions are always evicted. Roaring bitmaps are compressed and discontinuous so memory usage again remains bounded as subscribers come and go.
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Bit shifting blew my mind
Definitely take a look at a roaring bitmap. https://github.com/RoaringBitmap/roaring
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Protocol buffers database, a Key-Value database on the wire
Roaring bitmaps + btrees are a rock solid indexing approach. Alternatively, bleve has a lot out of the box but that's introducing a new datastore, basically.
h3
- H3: Hexagonal hierarchical geospatial indexing system
- Evaluation of Location Encoding Systems
- Not sure if this is the worst or most genius indentation I've seen
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A population density map of the state of Pennsylvania
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).
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[ANN] HexTree: geographical region-to-value mapping
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.
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What's everyone working on this week (34/2022)?
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.
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Surprising result while transpiling C to Go
> 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...
- Completely ignorant Newbie needing help with launching Ubers H3 Software.
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Anyone doing geospatial queries? NoSQL? Amazon Location Service?
Uber just released their library to perform geospatial indexing - https://h3geo.org/. This might be an useful building block for you.
What are some alternatives?
skiplist - skiplist for golang
S2 geometry - S2 geometry library in Go
boomfilters - Probabilistic data structures for processing continuous, unbounded streams.
Leaflet - 🍃 JavaScript library for mobile-friendly interactive maps 🇺🇦
bit - Bitset data structure
mapbox-gl-js - Interactive, thoroughly customizable maps in the browser, powered by vector tiles and WebGL
bitset - Go package implementing bitsets
starlink-coverage - Calculating some statistics about Starlink satellites
hyperloglog - HyperLogLog with lots of sugar (Sparse, LogLog-Beta bias correction and TailCut space reduction) brought to you by Axiom
s2geometry - Computational geometry and spatial indexing on the sphere
golang-set - A simple, battle-tested and generic set type for the Go language. Trusted by Docker, 1Password, Ethereum and Hashicorp.
maplibre-gl-js - MapLibre GL JS - Interactive vector tile maps in WebGL2