BorderPatrol

BorderPatrol lets you import a KML file and then check if points are inside or outside the polygons the file defines.

The KML file may have multiple polygons defined, google maps is a good source.

Examples

An example KML file can be found here: http://maps.google.com/maps/ms?ie=UTF8&hl=en&msa=0&ll=38.814031,-103.743896&spn=9.600749,16.248779&z=7&msid=110523771099674876521.00049301d20252132a92c&output=kml

To test if a point is in the region you can either pass a class that responds to x and y (like the provided BorderPatrol::Point class) or just pass a longitude latitude pair.

region = BorderPatrol.parse_kml(File.read('spec/support/colorado-test.kml'))
denver = BorderPatrol::Point.new(-105, 39.75)
region.contains_point?(denver) # true
region.contains_point?(-105, 39.75) # also true!
san_francisco = BorderPatrol::Point.new(-122.5, 37.75)
region.contains_point?(san_francisco) # false
region.contains_point?(-122.5, 37.75) # also false!

If you want to use your own point class, just define x and y as methods that correspond to longitude and latitude.

Pro Tip

You can make KML files easily on Google Maps by clicking "My Maps", drawing shapes and saving the map. Just copy the share link and add "&output=kml" to download the file.g

Dependencies

• Nokogiri

Known Issues

Polygons across the international date line don't work.

Acknowledgements

http://jakescruggs.blogspot.com/2009/07/point-inside-polygon-in-ruby.html for evaluating the algorithm.

http://github.com/nofxx/georuby/ for providing the bounding box code.