cdm/src/main/java/ucar/unidata/geoloc/projection/AlbersEqualArea.java
private double computeTheta(double lon) {
    double dlon = LatLonPointImpl.lonNormal(Math.toDegrees(lon) - lon0Degrees);
    return n * Math.toRadians(dlon);
  }
private double computeTheta(double lon) {
    double dlon = LatLonPointImpl.lonNormal(Math.toDegrees(lon) - lon0Degrees);
    return n * Math.toRadians(dlon);
  }
Compute theta

@param lon longitude
@return theta