cdm/src/main/java/ucar/unidata/geoloc/projection/AlbersEqualArea.java
private double computeRho(double lat) {
    return earth_radius * Math.sqrt(C - 2 * n * Math.sin(lat)) / n;
  }
private double computeRho(double lat) {
    return earth_radius * Math.sqrt(C - 2 * n * Math.sin(lat)) / n;
  }
Compute the RHO parameter

@param lat latitude
@return the rho parameter