Once you asked the person to leave your property (if you did) and he refused, he was trespassing. Georgia Code § 16-7-21 (b)(3) applies. If you had a fence and "No trespassing" signs, subsection (b)(2) would also have applied.
If you did not ask him to leave, and there were no signs notifying him to do so, then he wasn't legally trespassing unless he did at least $500 worth of damage, which it does not sound as if he did
If you (being an owner or occupant) notify a person in some other way than by a sign not to enter a property, it is still trespass if that person then enters without lawful authority.
In some US states, including Arizona, there are degrees of trespass, but as far as I could find there is no such thing as "third degree trespass" in Georgia.
(See also Property Owners & Injury Liability w/ Signage (US, WV) and the Wikipedia article on Tresspass)
Once an owner, rightful occupant, or an authorized representative of an an owner or rightful occupant asks someone to leave, they must do so (unless hey have some lawful authority to be present), and failing to do so is criminal trespass.
One can call the police to deal with a criminal trespasser.
According to Georgia Code § 16-7-21 - Criminal trespass:
(a) A person commits the offense of criminal trespass when he or she intentionally damages any property of another without consent of that other person and the damage thereto is $500.00 or less or knowingly and maliciously interferes with the possession or use of the property of another person without consent of that person.
(b) A person commits the offense of criminal trespass when he or she knowingly and without authority:
(1) Enters upon the land or premises of another person or into any part of any vehicle, railroad car, aircraft, or watercraft of another person for an unlawful purpose;
(2) Enters upon the land or premises of another person or into any part of any vehicle, railroad car, aircraft, or watercraft of another person after receiving, prior to such entry, notice from the owner, rightful occupant, or, upon proper identification, an authorized representative of the owner or rightful occupant that such entry is forbidden; or
(3) Remains upon the land or premises of another person or within the vehicle, railroad car, aircraft, or watercraft of another person after receiving notice from the owner, rightful occupant, or, upon proper identification, an authorized representative of the owner or rightful occupant to depart.