Designing a Basemap

Table of Contents

  1. Designing a Basemap
  2. Setting Up Your Workspace
  3. Download Data from the DataSF Website
  4. Refreshing a Folder in the Catalog Tree
  5. Changing the Map Projection of the Data Frame
  6. Changing the Map Size and Position
  7. Preparing the Layout
  8. Adjusting Line Weight and Color
  9. Cartographic Typography
  10. Skill Drill: Practicing Cartographic Typography
  11. Skill Drill: Choose a Map Theme
  12. Skill Drill: Finalizing the Poster

Adjusting Line Weight and Color

In this chapter, you learned about visual variables, the graphic representation of information using visualization techniques that clarify symbols and features from one another. Among the visual variables to consider for this activity are hue, saturation, and value, the three dimensions that characterize color.

For more information on the three dimensions of color, read the related section in Chapter 2.

When choosing a basemap color pallet, keep the map purpose and audience in mind. The goal of a basemap is to provide context for the primary data or theme. In this instance, the basemap will serve as the background for your choice of one out of two themes. You can choose the historical fire damage from the 1906 earthquake as the theme, or you can pick sea level rise and flooding. Whether it is fire damage or flooding, you want your theme communicated to the map reader clearly and effortlessly.

For this activity, I recommend choosing either a light color scheme or a dark color scheme for the basemap. Either one should have colors with low saturation, low value, or both. For example, a light color scheme might use light greys and pastels for the basemap features. A dark color scheme might use medium to dark greys instead. Your goal is to provide context without competing with your thematic data.

Start by arranging the layers in the Table of Contents using the following order from top to bottom:

  • neighborhoods
  • muni routes
  • streets
  • trees
  • buildings
  • parks
  • shoreline

You will work from the bottom up, starting with the shoreline layer. It will lay the foundation for the remainder of the map design. On the Table of Contents, click the colored rectangle under the shoreline layer. When symbol selector opens, choose a something neutral for the Fill Color. Set the Outline Color to No Color. For most of the polygon layers, you will want to remove the outlines.

An image of the shoreline symbol selector window
You can make quick edits to feature symbols and colors directly from the Table of Contents. Click to view the image in a larger size.

Repeat these steps for the parks, buildings, and trees, one at a time. Try to maintain your chosen color scheme throughout the process. You will need to remove the outlines for each of these layers. If necessary, use the Zoom In tool on the Layout toolbar to get a closer look at the details.

An image of the four SF foundational baselayers
The shoreline, parks, buildings, and trees make up the foundation of the basemap. This example uses a light color scheme. Click to view a larger sized image.

For linear features, such as the streets, you need to adjust both the color and the line weight. Turn on the streets layer. In the Table of Contents, click the symbol for the streets. By default, ArcMap sets the line width to 1.00. For this map, 1.00 is a little too heavy. Change the width to 0.75. Change the color to something that matches your chosen color scheme.

An image of the SF streets symbol selector window
The streets, MUNI routes, and neighborhoods serve as accents on the basemap. Click to view a larger sized image.

Repeat these steps for the MUNI routes. Because the MUNI routes are on top of the streets, you may want to choose a different width and color. The goal is for the map reader to distinguish between the two linear features while keeping both features relatively low in the visual hierarchy.

An image of the MUNI routes
This example uses a slightly thinner line weight and a lighter color for the MUNI routes.

You may be wondering why the neighborhoods layer is on top of the stack in the Table of Contents. For this map, the neighborhoods layer serves as an accent. Turn on the neighborhoods layer. Because the neighborhoods layer is on top, you also need to make the layer transparent. Open the neighborhood properties and navigate to the Display tab. Change the transparency to 90%.

An image of the neighborhoods display tab
The higher the number, the more transparent the layer will be. Click to view a larger sized image.

Remove the Fill Color. Change the Outline Width to 5.00. Choose an Outline Color that works with your chosen color scheme. It should be different enough so that these lines on the map will not be confused with the road layers.