The map visualization encodes crimes per square mile committed in the outlined district using color. The more saturated the color, the more crime per square mile. This information was calculated using the total number of crimes committed in each district divided by the district's area. Upon hovering over an outlined area, the district’s name will appear as a tool tip. Additionally, more details about the district will appear in a table in the upper left hand corner, below the “Show San Francisco Data” button. The table shows the precise number of crimes per square mile in the selected district, as well as the percentage of reports that resulted in arrest.
Below the map, there is a stacked bar chart that shows the total number of crimes committed and the number of crimes that resulted in arrest – sorted by total count. These two bars categories are encoded using color. Due to size constraints, I chose to show only 10 crime categories, which was decided by highest total count. The count is encoded by the height of the bar, with labelling on the y-axis (on the right), and the category of crime is on the x-axis (on the bottom). The title of the bar chart indicates the district that is being displayed.
In the map, you can see that the highest crime per square mile is in Tenderloin. This makes sense, as there is a high population density, large number of travelers, and a visible homeless population. With more foot traffic and people, the chances of a crime occurring is high.
In the bar graphs, you can see that Larceny/Theft is by far the most common crime committed in all districts. You can also see that the rate of arrest is low. This is likely because people report their possessions as stolen, but there is little evidence or man power to chase down the culprit. You can also see that violent crimes have a high rate of arrest. For example in Park district, almost 50% of the assault reports resulted in arrest.
It is apparent that although the contents of the top 10 crimes committed in each district varies slightly, the rate of crime (color of the district), doesn’t seem to have an effect on the rate of arrest. Tenderloin, which has the highest density of crime, has about the same rate of arrest as Taraval, which has less than a tenth of the crime density.
Data set:
Data set from data.sfgov.org - I used java to help make mini-datasets to help with speed. Click here to see the code.
Geojson data from data.sfgov.org
Code References:
I have to thank Prof. Sophie Engle for being such a good resource! Click here and here to take a look at the code I based my bars and map on.