Mapping numerical data associated with geographic locations is a task all GIS practitioners will eventually face.  One method of presenting such data is by using proportional symbols.  Learning how and when to use proportional symbols was the goal of this week’s lab. 

Some of the more specific objectives of the lab were:

-Getting familiar with using the Query Builder in ArcMap to isolate data

-Using both ArcMap and Adobe Illustrator (AI) to create proportional symbol maps

-Learning how to calculate symbol sizes by means of mathematical scaling

-Practice working with custom symbol templates in ArcMap and AI

-Creating circular labels in AI

The deliverables for the lab were proportionally symbolized maps of wine consumption for Western European countries using 2010 data.  Map 1 covered all Western European countries while Map 2 focused on seven specific countries.

For Map 1 I found it challenging to decide what orientation I wanted to the page to be.  I settled on portrait because of the mostly north/south spread of the countries based on using the Europe Lambert Conformal Conic projection.  Determining an appropriate number of symbol classes was also daunting but I decided that 7 classes gave an accurate representation of the data as opposed to using the 9 classes included in the instructions.  Because of the number of countries I chose to use a verdant tone color scheme so that each nation was easier to see with its associated symbol.  I think the contrast offers the viewer more information.  I chose circular symbols because I didn’t think the wine bottle image displayed consistently for all classes.

Map 2 used the same data set but was limited to seven countries and was created entirely in AI.  I chose an orange color to separate the seven countries from the surrounding nations displayed in a light gray.  A light blue background served as the water.  Label scaling, placement and creation were the most trying aspects to completing this map.  After working through the scaling routine a few times it became easier.  Placement of labels was interesting since not all the symbols fit neatly within the country’s borders.  I challenged myself and created the circular labels and am glad I did.  It’s a useful skill and adds a professional feel to the map.

Proportional symbols can be used to effectively convey map data in an easily digestible format for viewers.  This mapping technique is another valuable tool in the cartographer’s bag of tricks.