Color Between the Map Lines

Creating a custom map’s roads, rivers, and areas is often a balance between importing GIS data and drawing features with Illustrator tools like the Pen tool. When data is missing for areas like parks, school districts, or tourism zones, mapmakers must rely on Illustrator’s creation tools to fill in the blanks.

custom map of Clovis, New Mexico

Adobe Illustrator Shape Builder tool iconAmong Illustrator’s newest tools is the Shape Builder. Introduced with CS5, this tool behaves like a “live” pathfinder cursor that also caries a paint palette in its back pocket. It only needs paths like crisscrossing roads or intersecting boundaries to create and color new shapes in the space between paths. The Shape Builder can save time compared with drawing features with the Pen tool or using the Pathfinder panel.

1. Create a Parks Layer. The Shape Builder tool consumes paths as it makes new shapes so you shouldn’t rely on artwork from other layers you want to preserve. Instead, duplicate paths from other layers. If your map is like the example map above, city parks are mainly bounded by streets. So start by duplicating the Streets layer and renaming the duplicate layer “Parks.”

Not all city parks are bounded by streets. Some use streams, property lines, or other geographic features to define their boundaries. You’ll need to get these other paths into your Parks layer to use later when creating the parks.

For example, if a park is bounded by a stream, open the Streams layer, select the stream that borders the park, and duplicate its path (Copy and Paste-in-Front). In the Layers panel, drag the pasted path into the Parks layer. For a park with boundary that isn’t formed by a line in your map data or artwork, simply draw the boundary path using the Pen or Pencil tool. You don’t have to be precise about starting or ending points of the path; the path can cross other lines. When finished, select all of the paths on the Parks layer and paint them with the same stroke color. This will help cleanup after you finish creating the parks.

Adobe Illustrator selected map line

2. Set Options for the Shape Builder Tool. Before creating the parks, set some of the Shape Builder tool options by double-clicking its icon in the Tools panel or pressing Shift-M. In the Shape Builder Tool Options dialog, enable Gap Detection and choose a Gap Length. This helps connect the tool create a shape when the paths you select don’t intersect or overlap perfectly. Also, choose one of the Pick Color options (Color Swatches or Artwork) and make sure Cursor Swatch Preview is enabled. By enabling these coloring options, you extend the Shape Builder tool to serve as a paint palette so you can choose colors for the new shapes you create.

Adobe Illustrator Shape Builder options dialog

3. Select Paths and Create Park Shapes. Now you’re ready to select paths and make  shapes. If your Parks layer doesn’t contain a lot of paths, lock all other layers in the Layers panel and then choose Select > Select All. (The more paths selected, the slower Shape Builder will run creating a park shape.) Or choose the Selection tool and drag to select paths that surround the park area you will create. Don’t worry about selecting only the paths adjacent to the park. Just select a wider area around the park.

Adobe Illustrator selected map lines

With the paths selected, move the Shape Builder tool and hover over a city block where the park is located. You’ll see that a coarse pattern highlighting the area below the cursor. Because you enabled the tool’s color options previously, you can set the color fill of the shape you will create. Use the keyboard’s Up and Down arrow keys to select different color group swatches or move the Left and Right arrow keys to select a particular swatch. Hint: Open the Swatches panel when using the Shape Builder tool. It helps you see color groups or swatches as you navigate colors using the arrow keys.

Now click inside the city block, or, if a park extends across several city blocks, click and drag over the blocks. The result is a new park shape. Continue working across the map until all parks have been created.

Adobe Illustrator Shape Builder map area

4. Clean Up the Parks Layer. Your Parks layer comprises the color-filled shapes created by the Shape Builder tool and all of the leftover paths. You’ll want to discard the leftovers so the Parks layer only contains the park shapes. With all layers locked except the Parks layer, select a non-park path and choose Select > Same > Appearance. Press the Delete key or choose Edit > Clear to remove everything from the Layers path that isn’t a park.

5. Turn the Parks Layer into GIS Data. If you use Avenza MAPublisher plugins to import and process GIS data, you may want to convert the Parks layer into data you can manipulate or export later. Because the Parks layers started as line features (streets), you’ll need to change the Parks artwork into MAPublisher Area features. (With the first click of the Shape Builder tool, all MAPublisher feature data and attributes were deleted, leaving the artwork as non-GIS Illustrator graphics.) To turn the Parks artwork into GIS data, be sure the MAP Views panel is open (Window > MAPublisher >MAPublisher MAP Views). Now drag the Parks layer down into the Non-MAP Layers half of the panel. Verify that you want to remove MAPublisher data. Then drag the Parks layer back up into the MAP View and choose Area as the Feature Type in the Undefined Layer dialog box. Your parks are now GIS data. From here you can perform GIS operations like naming each park or assigning classes like “playground” or “softball” to parks using the MAP Attributes panel.

MAPublisher remove map data warning

MAPublisher define layer dialog

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Creating parks from streets and other lines demonstrates one of the functions of the Shape Builder tool. You can find more information about the Shape Builder tool in the The Adobe Illustrator CS6 WOW! Book. Also, there are many tutorials online covering the Shape Builder. We recommend Mordy Golding’s Real World Adobe Illustrator tutorial here.

Article copyright © 2013 by Cartagram, LLC

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