Your ICoordinateSystemTransformation class is the one that will actually handle the transformation of data. There are four methods that you must implement:

double[] coordTrans(double x, double y)

double[] coordTrans(double x, double y, double z)

double[] invCoordTrans(double x, double y)

double[] invCoordTrans(double x, double y, double z)

The coordTrans methods are used to transform the given coordinates with your desired transformation. The double array returned needs to be the points in the same order that they are passed to the method, such that returnDoubles[0] is the x variable, returnDoubles[1] is the y variable and so on.

The invCoordTrans methods are used to run the inverse transform on the coordinates, and the array returned is constructed in the same way as the previous methods.