Module 6 GIS 6005
This week Module 6 has introduced us to proportional symbol and bivariate mapping. During this module we learned to explore data and determine what method is best used to present the data particularly when there is more than one variable and there is a link or potential link between the data.
We started off with proportional symbol mapping. Proportional symbols are good way of simplifying data on maps and making it easier to understand. Unfortunately proportional symbols take a good amount of effort to get just right. Symbol size, shape and color are all vary important when using proportional symbols.
Our task was to make a proportional symbol map that demonstrates job losses and gains in the US between 2007 and 2015. When working with this kind of data we know we are going to encounter negative values. ESRI ArcPro is unable to symbolize negative values. In order to overcome the inability of ArcPro to symbolize negative values we had to create extract negative values from our original dataset and create a new feature class with negative values converted into positive values by utilizing the field calculator. By creating a second feature class we could represent negative values as a proportional symbol. When showing two feature classes with the same data it is important to keep parameters for your symbology equal or the reader could be misled. My final proportional symbol map below.