Proj4js

A proj4js (http://trac.osgeo.org/proj4js/) fork for experimenting with some potential API cleanups. Very much a work in progress.

Proj4js is in many ways an excellent library, it is very powerful, but the API is a bit quirky and contains quite a few surprises.

The goal of this project is to try to construct a more friendly API than what is available today.

These are the main issues that I see with proj4js today:

To get proper error handling in place you need to override Proj4js.reportError, otherwise Proj4js will either silently fail or chose some arbitrary default value (like wgs84 for a failed Proj4js.Proj construction or the point itself in case of a failed transform).
The Proj4js.Proj constructor is full of surprising side effects.
- You can't construct a Proj from proj4-def, the constructor only takes an srsCode. This makes it impossible to construct an anonymous Proj.
- To construct a Proj you need to first add the proj4-def to the Proj4.defs dictionary with its srs code as key
- However if the proj4-def isn't available in the dictionary the constructor will silently turn itself into an asynchronous call to try to load the proj4-def from the web (first from a subdir from where proj4js.js lives and then from http://www.spatialreference.org/). Fortunately the constructor takes a callback.

The asynchronous loading of proj4-defs can be handy at times, but I want to be able to decide for myself when I want this behaviour and not.

So the main goals currently is:

Strip away all asynchronous downloading of proj4-defs and instead let Proj4js.Proj take a proj4-string as part of its arguments.
Create a library or function, taking inspiration from the removed code above, for loading proj4-defs from remote locations.

Other possible goals:

Compile & Install

You need node 0.10.x and npm installed. To compile is then as easy as

npm install

and then just copy the wanted version from dist/