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proj4erl

proj4erl is a NIF-based binding for PROJ.4 library.

It supports three API calls

• init/1 - equivalent of pj_init_plus, returns opaque value which should be used as a reference to initialized projection (equivalent to projPJ type)
• get_def/1 - equivalent of pj_get_def, returns string
• transform/3 - equivalent of pj_transform

Here is an example of usage:

    {ok, WGS84} = proj4:init("+init=epsg:4326"),
    {ok, CRS2180} = proj4:init("+init=epsg:2180"),
    P = {21.049804687501, 52.22900390625},
    {ok, P2} = proj4:transform(WGS84, CRS2180, P),
    {639951.5695094677, 486751.7840663176} = P2.

Initialized projPJ references are being automatically garbage collected.

Feel free to fork and send pull requests!

Setup

Clone the project and run (on Ubuntu; adapt apt-get command to install proj4 development files on other systems):

$ sudo apt-get install libproj-dev
$ make

TODO

• ad-hoc transform calls, with implicit initialization of projPJ and it's caching
• support for linestrings, rings, polygons for speed