Sunday, April 2, 2017
Dot Density- GIS3015
This week's lab was Dot Density mapping. Dot mapping is widely used when raw data has been collected and the map is intended for illustrating the lack of uniformity in the data/phenomena. Each dot represents a certain amount and placed where the phenomena is likely to occur or has previously occurred. The class mapped 2000 census data for populations throughout south Florida. In addition to simply placing dots on the map (1 dot symbolizes 14,000 people) we used a mask feature to show patterns more effectively. The mask feature allowed us to specify that the dots were only placed where there is urban land. Many of the dots were initially on water and places that it's highly unlikely there was truly anyone living there! To give a reference of location we were instructed to chose 3 major cities and map those, as well. I think that in addition to reference, the end user could use these major cities and make inferences based on dot density and the relationship between population and major cities.
The masking feature takes up an enormous amount of processing and we were warned to be patient. I noticed in the class discussion board that a lot of people were having trouble with ArcMap crashing, so I decided to build my map on a UWF campus computer instead of using the server at home. This helped a lot and I only had ArcMap crash once white it was masking and drawing all the data for surface water. I chose the blue background color because it shows the edges of Florida really well. The varying greens for the basemap and surface water are especially aesthetically pleasing.