In the traditional "pin" approach to maps, the pin essentially "points" to the actual latitude/longitude. Alternatively, you could have a symmetric (e.g. circular) icon that is essentially centred on the latitude/longitude. Have there been any usability studies or guides for when to use which type?
Example map pin:
Example symmetric marker:
My question is whether to have markers "point" to their exact location (i.e. using a "pin"), or whether to centre them on top of that exact location (e.g. using a circular icon). In neither case am I referring to clustering, as I will not be clustering markers.