polyline v0.1.0 Polyline
Encode and decode Polylines to and from List of {lon, lat} tuples.
The encode functions accept a precision parameter that defines the
number of significant digits to retain when encoding. The same precision
must be supplied to the decode or the resulting linestring will be incorrect.
The default is 5, which correlates to approximately 1 meter of precision.
Examples
iex> Polyline.encode([{-120.2, 38.5}, {-120.95, 40.7}, {-126.453, 43.252}])
"_p~iF~ps|U_ulLnnqC_mqNvxq`@"
iex> Polyline.decode("_p~iF~ps|U_ulLnnqC_mqNvxq`@")
[{-120.2, 38.5}, {-120.95, 40.7}, {-126.453, 43.252}]Summary
Functions
Decode a polyline String into a List of {lon, lat} tuples
Encode a List of coordinate tuples into a Polyline String. Also works with
Geo.LineString structs (see https://hex.pm/packages/geo)
Functions
Decode a polyline String into a List of {lon, lat} tuples.
Examples
iex> Polyline.decode("_p~iF~ps|U_ulLnnqC_mqNvxq`@")
[{-120.2, 38.5}, {-120.95, 40.7}, {-126.453, 43.252}]
iex> Polyline.decode("_izlhA~rlgdF_{geC~ywl@_kwzCn`{nI", 6)
[{-120.2, 38.5}, {-120.95, 40.7}, {-126.453, 43.252}]Encode a List of coordinate tuples into a Polyline String. Also works with
Geo.LineString structs (see https://hex.pm/packages/geo).
Examples
iex> Polyline.encode([{-120.2, 38.5}, {-120.95, 40.7}, {-126.453, 43.252}])
"_p~iF~ps|U_ulLnnqC_mqNvxq`@"
iex> Polyline.encode([{-120.2, 38.5}, {-120.95, 40.7}, {-126.453, 43.252}], 6)
"_izlhA~rlgdF_{geC~ywl@_kwzCn`{nI"
iex> "LINESTRING(-120.2 38.5, -120.95 40.7, -126.453 43.252)"
...> |> Geo.WKT.decode
...> |> Map.get(:coordinates)
...> |> Polyline.encode
"_p~iF~ps|U_ulLnnqC_mqNvxq`@"