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A Ruby ffi wrapper for the PROJ.4 Cartographic Projections library.
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PROJ.4 Ruby Bindings via FFI


  • the ffi extension for Ruby.

  • the PROJ.4 library. This release has been tested with version 4.8.0.

Ruby versions known to work:

  • Ruby MRI 1.9.3, 2.0+, 2.1+ and 2.2+

  • JRuby 1.7.22+

  • Rubinius 2


ffi-proj4 tries to support most of the features and interface found in the mostly-native proj4rb project, but while proj4rb uses some private interfaces to pull unit and datum information out of PROJ.4, we can't replicate that functionality as we rely on strictly public interfaces. Hopefully some of the internal interfaces required to replicate the functionality of proj4rb will be made public, but until then, ffi-proj4 will be missing some proj4rb functionality and cannot act as a drop-in replacement for any applications requiring unit and datum sniffing.


This gem is licensed under an MIT-style license. See the MIT-LICENSE file for details.

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