To do content analysis of graffitti, first i would Observe the graffitti.
From the quality of the graffitti, we could easily tell whether it just a simply act of vandalism (and may be identified by finding symbol that often used within a certain gangs) .or it is made with someone with art skills.
After that , i will pinpoint the quality assesment with the location of the graffitti (for example whether it's a near popular hangout place for teenagers)
