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Part IV: Create a (Graphic) Mask Layer

Because we deleted some/all of the Clipping Paths (which we had to do in order to Un-Group the Grouped layers) some of the map data probably now extends beyond the edges of the original data frame. In Illustrator, the data isn't actually cropped to the frame, but instead is simply "masked" by a layer that covers the area outside of the data frame. A Clipping Mask (in the simplest sense) is just a shape (like the border of your map frame) that is used to virtually 'clip' the display, so that anything within the shape is shown and anything outside of the shape if hidden (masked).

Since we have lost these masking ("clipping") layers, we will have to recreate them or come up with another method of masking the areas outside of our frame that we don't want shown. The "Illustrator" way to do this would be to create a new Clipping Mask layer, and you are welcome to do this if you like (using Adobe help files and tutorials). But doing so has some downsides and for our purposes a simple graphic mask would work just as well. To do this (create a simple graphic mask) we will add a new Layer to our file. In that layer we will create four rectangles (or whatever shape you like) that frame the map. These new polygons will mask (cover up or hide) the portions of the data we don't want to show).

Creating a New Layer

Now that we’ve removed the Clipping Layers some of the map data will show beyond what was the extent of your map frame. This will show up in your final printed product unless you remove or mask (cover) it. Rather than using a Clipping Layer (which we could recreate if we wanted to) we will simply create a mask to hide the artwork that you do not want to show.

  1. Create a new layer:
  • At the bottom of the Layers Panel are 5 icons:
    • Locate Object
    • Make / Release Clipping Layer
    • Create new sub-layer
    • Create new layer
    • Delete selection

 

 

  • Click the Create new layer icon
  • Double-click on the newly created layer to rename it Mask
  • Drag the Mask layer to the top of the Layer list (click, hold and drag it to the top)
  1. Lock other layers: Before we begin editing the Mask layer, lock the other layers so that they can’t be selected, moved, changed or deleted inadvertently
  • Click on the grey box beside the eyeball icon to lock each layer (a padlock icon appears)
  • Note you can click on the top lock icon and drag down the list to quickly lock all of the layers

Adobe Illustrator Tools – Create Polygons to Use as a Graphic Mask

On the left side of your screen is the Tools panel. The Tools panel contains tools for selecting items, adding text, erasing features, changing colors, etc. Hover over the different tools to see the tool tips for an idea of what the different tools do. Refer to the Help section if you want to try some of these out… near the bottom of the Tools panel is are the Fill and Stroke tools. The “Fill” is the color of an object (like the fill of a polygon). The “Stroke” is the outline of the object. The Fill and Stroke tools are used to set the colors of the currently selected object’s fill and/or outline, or to specify the colors of new objects to be added. Note that clicking on either the Fill or Stroke icon will bring it to the foreground. Double-clicking either the Fill or Stroke icon will open the Color Picker. Using the Color Picker you can choose a color or specify a color by number.

 

 

3. Double-click the Fill icon (the upper left icon of the two paired icons) to open the Color Picker for the Fill

  • In the Color Picker choose a color (preferably a light color, possibly white)
  • Click OK (the Fill icon should now be the chosen color)

4. Single-click the Stroke icon (the lower right icon of the two) – do not open the Color Picker (click OK to close it if you opened the Color Picker by mistake)

  • With the Stroke icon selected, click the ‘None’ icon just below the Stroke icon in the Tools Panel (a small box with a red line through it)
  • The Stroke icon should now have a red line across it (and no color shown)

5. Now, with the color set for the Fill and No Stroke specified, choose the Rectangle Tool from the Tools Panel (a rectangular icon)

6. Using the Rectangle Tool draw a box beside your data frame

  • Starting at the top left corner of the page, draw a box that goes from the top of the page to the bottom of the page and from the left edge of the page to the left edge of the data frame
  • If you need to adjust the size of your box use the Selection Tool (a black arrow) to click and drag the edges or corners of your box
  • Don’t worry (for the moment) about covering up things like the page neatline, title, scale bar, etc. – we’ll fix that in a moment

7. Repeat this process to create 3 more rectangular boxes (as part of the same Mask layer): one each for the top, bottom and right side of the page, covering everything on the page except for the map frame itself

8. Now we need to move the map elements above the Mask layer (in the Layer list) so that they are visible again

  • Identify by turning layers (or sub-layers) On and Off which layer contains the Title (assuming the title is outside of the map frame and thus currently being covered by the mask)
  • Move (click and drag) this layer to the top of the Layer list (above Mask) so that the title is now visible even when the Mask layer is on
  • Repeat this process to identify whatever other layers (or sub-layers) contain elements that are outside of the map frame (page border, map credits, etc.) and likewise move these above the Mask layer
  • Be sure to also move the layer with the data frame border above the mask
  • Some elements may be combined with other layers that are part of the map
  • You can move just the map element sub-layers as needed
  • You’ll need to un-lock the layers before you can move a sub-layer

 

 

The newly created Mask layer (above)  

The same map with title and map elements moved above the Mask in the Layer list (below)

 

 

(Note: In the example above an ocean fill has also been added… which we’ll do shortly…)

9. SAVE your .ai file (optionally using Save As and creating a new version…)