Aggressive graffiti is defined as graffiti written by gang members that crosses out the pre-existing graffiti of a rival. Sometimes it can include disrespectful taunts and threats against a rival gang and/or its members, but as it is defined here, it must always cross out the other graffiti.
Often times, gang members will write the name of their rivals and cross out it themselves, and this can be confused as aggressive graffiti because of its threatening remarks.
In this case the graffiti is not considered aggressive because the graffiti was written by the same group, and a rival group never contested the messages.
The places of aggressive graffiti are locations were gang members from rival groups came to the same place to write their identity and cross out their rivals.
Identifying Aggressive Graffiti - Definition

This photo show several trips made to this spot by two rival gangs on a street that serves as the boundary between their territories. .