New York City and Rats- comparing the number 311 calls to the number of rat sightings.



New York, as a city, has the reputation of having cheap dollar pizza, delicious bagels and noteworthy parks such as Central Park, squirrels live in the parks and hang out where trees are more abundant, pigeons are seen everywhere while you’re outside, without even seeing one in front of you, you know there are rats walking with you on the streets. Rats being a pest seemed to have progressed alongside humanity, and it is 100% because of how we progressed as a society. Trash by the curbside is undoubtedly one factor that contributes to the survival of rats, not only could it contain food scraps, it also acts a shelter for the rats. In recent news, NYC officials are looking to impose a trash collection schedule shift, by restricting the time residents could leave trash on the curbside to be collected, in hopes of reducing the population of rats in the city.

Trash by the curbside on a street in the neighborhood of Bedford-Stuyvesant.

For this report, I would like to discover if there is a correlation between the number of 311 calls and a separate report of sightings of rats New York City neighborhoods. To give a brief introduction, 311 calls give the caller access to non-emergency City services and info about City government programs, and is also a portal that is used to take in complaints from NYC residents. This report serves as an exercise to utilize ArcGIS, transforming data into easy to digest visualizations that communicates a story.

Materials and Methodology

As the main focus of this exercise is utilizing ArcGIS, I’ve opted to use data found on ArcGIS, the materials selected for this piece are as follows: NYC Rat Sightings 2019, NYC 311 Calls by ZIP Code Feature Service. My process starts with a search within the ArcGIS Online archive, finding and making sure the material reflects the story I’m trying to tell. Then I continued with loading the two layers I’ve selected on the base map.

After saving the layers, I moved forward with opening the map in the Map Viewer. The base map to changed to a darker palette so that the colors I’ve selected could be highlighted and brought to the viewer’s attention immediately. The layers at this point present some form of hierarchy, but not to a point which it could be understood easily. The range of blues, on a scale of intensity of hue, represents the number of calls made in a specific ZIP code area, given the darker the hue, the more the number of call in an area; while the orange dots represents the amount of rat sightings in a given location. This mode of view might be informative for the average viewer but does not provide any substantial information on first glance.

To allow the map to communicate the story I want to communicate, I’ve decided to aggregate the orange dots so that it clusters and shows a number within each of the cluster bubble. As seen in the screenshot above, this allows both the ZIP code map and the rat sightings map to co-exist and present itself with a story through a visual hierarchy.


Final map illustrating the number of 311 calls in a ZIP code area in addition to the number of rat sightings at a specific location.

From the final map, we can see that there could possibly be a correlation between rat sightings and the number of 311 complaints made. Higher amounts of rat sightings coincide with higher numbers of 311 complaints. The conclusion of course cannot be made using this data since many other factors need to be considered. The number of rat sightings might be a lower number compared to the actual number of sightings since people who were willing to make a complaint is more likely to have a more immediate interaction with rats, in addition, the number of 311 complaints could have other forms of complaints included. This being said, the relationship we see in the map gives us an initial insight, as well as, reason to hypothesis that those given areas are more likely to have a higher concentration of rats.


This exercise has helped me use ArcGIS to express a story I wish to convey using visual elements, and although I believe I have done that to a comprehensible extend, there is more I could add to the map to tell a fuller story, with more data points. Given another opportunity to explore this topic, I would include more data points into the mix, given, a larger database that includes data of rat sightings especially in more recent years to see if the number of sightings has increased. I would also add a qualitative element to the story, exploring New Yorkers experience with rats and explore another side of the story by measuring New Yorker’s feelings when dealing with rats and the ways they are contributing in decreasing the population of New Yorker rats.