The term “choroplethe map” was introduced 1938 by the geographer John Wright in “Problems in Population Mapping”. (source, wikipedia). It is the communication between cartographer and audiences. It explains rates, densities and proportions, I think this is the point where GiS researchers and Epidemiologist have fun together 🙂

\Here right clicking on the layer, then properties ”general tab and ranming the layers help. One should be familiar with ‘insert’.

Already mentioned in previous post about attribute tables: we have to go to attributwe tables and then add field ..

New HIV cases per thousand population. New breast cancer cases per thousand population in the Queens.

Now i am really impressed with GiS software, how elegantly it gives histogram here…