/s2_cells

maps latitude and longitude to S2 Cells https://s2geometry.io/

Primary LanguageCrystalMIT LicenseMIT

Crystal Lang S2 Cells

CI

Maps Lat Lon coordinates to S2 Cells. Useful for things like storing points in InfluxDB

Installation

  1. Add the dependency to your shard.yml:

    dependencies:
  s2_cells:
    github: spider-gazelle/s2_cells

  2. Run shards install

Usage

require "s2_cells"

# index a location in your database
lat = -33.870456
lon = 151.208889
level = 24

cell = S2Cells.at(lat, lon).parent(level)
token = cell.to_token # => "3ba32f81"
# or
id = cell.id # => Int64

# find all the indexes in an area
p1 = S2Cells::LatLng.from_degrees(33.0, -122.0)
p2 = S2Cells::LatLng.from_degrees(33.1, -122.1)
cells = S2Cells.in(p1, p2) # => Array(CellId)

# then can search your index:
# loc_index = ANY(cells.map(&.id))

Reference

a crystal clone of https://github.com/sidewalklabs/s2sphere