Hi Chris,
I need to do similar conversion of California II State Plane in US Survey feet to geographic coordinates in decimal degrees. I am not totally comfortable with python but need to have it in python. I updated the parameters in California values. But not getting desired output. Here is the updated part of the script your wrote in California values:
A = 20925604.47 ## major radius of GRS 1980 ellipsoid, feet
Ec = 0.0818191910435 ## eccentricity of GRD 1980 ellipsoid
Ec2 = Ec * Ec ## eccentricity squared
AngRad = 0.017453292519943299 ## number of radians in a degree
Pi4 = 3.141592653582 / 4 ## Pi / 4
P1 = 38.33333333 * AngRad ## latitude of first standard parallel
P2 = 39.83333333 * AngRad ## latitude of second standard parallel
P0 = 37.66666667 * AngRad ## latitude of origin
M0 = -122 * AngRad ## central meridian
X0 = 6561666.66666667 ## False easting of central meridian, map units
And here is the snapshot of Data Source:
Unsure where the problem is. If it is due to no parameter for False northing or...?
Basically, the sample CA State Plane II x,y: 7079975.52661,2184310.50409 should give me: 39.1457869, -120.1722625 and if I run your code with above updated parameters, I am getting: 43.642324406, -120.048031426.
Any ideas how to fix that would be great!!!