Dot Mapping

Module 10 – Dot Mapping

For this week’s assignment we were asked to create a dot map (also known as a dot density or frequency map).  We were asked to import the South Florida shapefile into AcrMap 10.3 which only showed the 23 counties of the state. We then imported an excel spreadsheet that contained population data for the counties; we then join the files by county names. We also added urban land and surface water shapefiles and locations of some major cities.  We were also asked to add a north arrow, legend, scale bar and title to the map.

Dot maps can be represented as one-one, which would be better for smaller geographical areas or one-many, which is better for larger geographical areas.

Dot / Density maps can only use conceptual or raw data. When using dot mapping, some criteria should be considered: when you have discrete data occurring at points, when you want to compare distributions of related phenomena, and when you want to portray variations or patterns in density.

There are some advantages to dot maps that are very easy concepts to understand: for example, they are effective for showing variations of phenomena that exist in large quantities. This type of map is most commonly used in the agricultural maps.

There are also some disadvantages: it is hard to estimate density, and the map reader could interpret the dot to represent a single occurrence.  This type of map should not be used for large scale maps or when your data is continuously distributed.

This was a good and at the same time a frustrating assignment. On the good side, I liked bringing  in and joining two different file types to create one larger data file to pull the data from. On the frustrating side were the dots and trying to get them to fall in the proper place. There where many times the dots were all over the map, therefore I had to go over the lab instructions several times before they finally fell in to place.