Two words are used in french to describe the profession consisting in doing sundials :
1. The Gnomoniste's work is to calculate the exact position and informations who figure on the sundial.
2. The "cadranier" decides and realises the look of the sundial. Doing it beautiful is important to read the time correctly and easily.
Many people are the gnomonist and the cadranier unless you have a team working with you. But the gnomonist finally decides and has the responsibility of the final subdiaphragmatic.
The origin of the word "gnomonist" is "gnomon". The "gnomon" is a vertical stick giving the height of the sun. The first sundials were mostly "gnomons" until people realised that you have better to use a polar style parallel to the north-south poles axis or derivated systems of polar style.