I'm new to Carto, and using any of the file types Carto relies on, so treat me as a complete beginner. I'm trying to create a heat map for the number of road casualties in 2015 in England.
I used a shapefile from the ONS which includes the geometrical data of all the different authorities in England, and uploaded that to Carto. This seemed to work, because the map is displaying the borders between each authority
However it wouldn't work with my CSV file, which included the data for the casualties in each authority. So, I inserted the geometrical polygon data from the shapefile for each authority on my CSV file manually, and deleted the shapefile. The above photo is displaying from just using the CSV file with the added polygon data.
Below is a photo of the spreadsheet in Carto.
While the polygon geometry data is working, it's not properly reading the Casualties column, and isn't allowing me to create any analysis from this to make a heatmap. I'm not sure if I'm just not understanding the interface properly, because it is reading the casualties to some extent, shown by the numbers in the right locations below.
What I'm asking, is how do I get these numbers into something more like a heatmap, as shown in the first photo, but without the values between each colour making the majority of the map purple. I can't seem to find a way to change how Carto quantifies the numbers.