Picture relative dating
Excavation: Archeologists excavate buried cultural remains to both gather information about past human behavior and to preserve and protect cultural resources from destruction, either from human or natural processes. Discussed below are the three major types of dating used in archeology – relative dating, chronometric dating, and absolute dating – and some of the more popular methods employed in each general category.
The buildings on the Athenian Acropolis were important for trade and worship.
In the Southwest, and particularly in CRM, there are several defined types of survey: Remote Sensing: Remote sensing in archeology employs a wide variety of aerial and satellite imaging, as well as radar, sonar and lidar, to build landscape images useful for recognizing archeological materials not visible to ground crews.
Many remote sensing techniques rely on portions of the electromagnetic spectrum, such as infrared, that humans are typically unable to see.
You will find the essential part of the answer to your question in this "Socratic" link: What remains to be seen is: when should you use the one rather than the other.
Relative dating is useful during field work to measure, for instance, the throw of a fault, or to re-instate the missing part of a stratigraphic sequence.