Meeting 03 - Cartography 101

Meeting Goals

This course meeting has an emphasis on the following goals:

1. Apply gestalt principles to map reading and map design
2. Design ggplot2 maps with both figure and ground layers
3. Revise ggplot2 maps to use different color ramps
4. Employ different break algorithms to “bin” data together on a map

Before Class

Tasks

Please complete the tasks listed on the syllabus, and see Blackboard for the entry ticket link.

During Class

Agenda

1. Exercise 1 - Discussing Map Layers and Cartographic Choices
2. Exercise 2 - Complicating Our ggplot2 Maps
3. Break
4. Lab-03 and one-on-one meetings

Exercise 1 - Discussing Map Layers and Cartographic Choices

To illustrate some of the points about gestalt principles and color in the meeting prep video, please consider the following questions as a group after taking a look at this map of Ozark National Senic Riverways, a National Park Service resource in southern Missouri.

1. What do you think are the ground layers?
2. What do you think are the figure layers?
3. How is the gestalt principle of nearness used?
4. How is the gestalt principle of similarity used?
5. What do you think is the hierarchical organization of layers?

Exercise 2 - Complicating Our ggplot2 Maps

To apply some of our gestalt principles, and also introduce some tools for working with color, we’re going to add some complexity to the way we’re been using ggplot2 for mapping. Our goal is to load some data saved in several shapefiles and then:

1. Create a map using ggplot() and several instances geom_sf()
2. Manually alter color of layers
3. Illustrate using viridis and RColorBrewer to create palettes for thematic maps
4. Use a custom function to create map breaks

All of the materials are available in our meeting GitHub repo.

After Class

The Lab-03 instructions are available in module-1-cartography or can viewed online here. You’ll need to create a new .Rproj for it in your assignments repository and then create a static map of St. Louis showing the extent of owner occupied housing in the city. This map should include the Mississippi River and local highways as ground layers, and include map breaks as well as a viridis or RColorBrewer palette of your choice.