Marginalia Design
In addition to a legend, your maps will often contain other supporting graphic elements such as a scale bar and north arrow. Similar principles apply—you should make your design as simple as possible while still supporting the reader’s understanding of the map. Commercial GIS software such as ArcGIS permits you to easily add accurate scale bars to your map. These will automatically match your map’s scale, and dynamically update if you re-scale your map within your layout. When it comes to visual design, however—be wary of GIS defaults. You will typically have to make manual simplifications to these elements, scale bars in particular.
Figure 2.7.1 shows examples of default scale bar designs inserted into a map layout in ArcGIS, alongside illustrations of their appearance after manual adjustment.
Like making a legend, the first question you should ask yourself before designing a north arrow for your map is: do you need it? Depending on the map projection you use, the direction which points north may not be consistent across your map—in this case, a background grid may be more appropriate. Most maps do use a north arrow, however, and if you do use one, similar conventions to scale bar design exist. Aim to make your design as simple as possible without sacrificing comprehensibility.
Student Reflection
View the two scale bars in Figure 2.7.3. In general, as described in Figure 2.7.1, the top scale bar is considered better design. Can you think of a map for which the scale bar at the bottom would be more suitable? Why would it be?
