There is no such thing as a sundail or a clockorigin.
yes ,actual navigation use electronic navigation and paper one soo they need compas and sundails
Sometime in the B.C.
The shadow of the sun on sundials changes throughout the day as the sun moves across the sky. This allows one to estimate the time.
So they could tell the time. This helped them greatly: from leisurely organisation of meetings to fighting battles and trade. When the sun rays hit the dial, the shadow indicates what time it was.