This map is done by Portland police bureau and criminal justice students at PSU in research of crime of 2009 to 2013 for crime.
Through these maps objectives such as the crime rate, population/density of people, the high income and low income groups, safe area/ areas under police control and many more aspects can be extracted. The maps are shown in a way that it not only represents the areas under high /low crime but, also the reason of the crime, like the one we see in bicycion of Portland isle map or domestic map, the centre portion have the least crime with respect to overall crime in the city. that means people are safe at public places where density of people is maximum and thus criminals target those areas at less amount of time.
In this map crime color is use for parks. White color use for below average ,yellow color for average ,orange color for above average an of crime are less in the center as people amounted red color use for well above average.