Rolyrine

Fast Google Polyline encoding/decoding for Elixir, powered by Rust NIFs.

Uses the georust/polyline crate via rustler_precompiled for ~4-8x speedup over pure Elixir implementations.

Installation

Add to your mix.exs:

def deps do
  [
    {:rolyrine, "~> 0.1.0"}
  ]
end

Usage

# Encode coordinates to polyline
Rolyrine.encode([{-120.2, 38.5}, {-120.95, 40.7}])
#=> "_p~iF~ps|U_ulLnnqC"

# Decode polyline to coordinates
Rolyrine.decode("_p~iF~ps|U_ulLnnqC")
#=> [{-120.2, 38.5}, {-120.95, 40.7}]

# Decode with different output formats
Rolyrine.decode("_p~iF~ps|U_ulLnnqC", format: :lon_lat)
#=> [%{lon: -120.2, lat: 38.5}, %{lon: -120.95, lat: 40.7}]

# Use precision 6 (e.g., for OSRM)
Rolyrine.encode([{-120.2, 38.5}], precision: 6)
Rolyrine.decode("_izlhA~rlgdF", precision: 6)

Supported Coordinate Formats

Encoding auto-detects format from the first element:

Decoding defaults to tuples; use :format option for maps.

Building from Source

Set ROLYRINE_BUILD=1 to compile the Rust NIF locally (requires Rust toolchain):

ROLYRINE_BUILD=1 mix deps.compile rolyrine

License

MIT