FlexiblePolyline

The flexible polyline encoding from heremaps is a lossy compressed representation of a list of coordinate pairs or coordinate triples.

It achieves that by:

1. Reducing the decimal digits of each value.
2. Encoding only the offset from the previous point.
3. Using variable length for each coordinate delta.
4. Using 64 URL-safe characters to display the result.

For more information, visit: https://github.com/heremaps/flexible-polyline

Installation

Add this line to your application's Gemfile:

gem 'flexible_polyline'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install flexible_polyline

Usage

Encode:

 FlexiblePolyline::Encoder.encode(third_dim: 1, precision: 8, third_dim_precision: 8, positions: [[-96.628241002595274, 34.155307026461529, 228.390420353746407]])

=> "B4gBnq_r-_R-suzyrGm_vgqxqB"

Decode:

FlexiblePolyline::Decoder.decode('B4gBnq_r-_R-suzyrGm_vgqxqB')

=>

{"header": {"precision": 8, "third_dim": 1, "third_dim_precision": 8}, "positions": [[-96.628241, 34.15530703, 228.39042035]]} 

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/ioki-mobility/flexible_polyline.

License

The gem is available as open source under the terms of the MIT License.