"Fade to white background" effect

By Aileen Buckley, Mapping Center Lead

Buffer vignettes symbolize the interface between two areas. They are often used to show the land-water interface by gradually fading blue at the coast into white or vice versa. You can also use them to fade the map out into a white background. These types of vignettes are created using buffers that are symbolized in a special way.

Note — as described this only works on white backgrounds. See the two examples at the end to see how the data frame’s background can be coordinated with the buffer vignette for different effects on along coastlines.

Create buffers for the vignette

  1. In ArcToolbox, click Analysis Tools.
  2. Click Proximity toolset.
  3. Click Multiple Ring Buffer.
  4. Double click the tool.
  5. Set the input features that constitute the perimeter of your study area.
  6. Call the output feature class bufferVignette.
  7. To make 16 rings that decrease in size from 5 miles to one mile, enter these distances in ascending order: 5, 9, 13, 16, 19, 22, 24, 26, 28, 30, 31, 32, 33, 34, 35, 36. The last buffer is used to fill in the rest of the data frame as you will see below. Use the Plus sign to add each new number. (The numbers you use are scale dependent—it’s really more a matter of measuring so use the Measure tool to determine the width of the buffer and then divide that distance using the proportions shown above as an example.)
  8. Make sure you set the Buffer units to Miles.
  9. Click OK.
  10. Rename the new layer Buffer Vignette in the Table of Contents and move it below the State Outline and above the County Outline.

Adding fields to a table

  1. Right-click the Buffer Vignette layer in the Table of Contents and click Open Attribute Table.
  2. Click Options in the table to which you want to add a field.
  3. Click Add Field.
  4. Type the name of the field. Use Xpar.  This is the abbreviation for “transparency”.
  5. Click the Type dropdown arrow and click the field type. Use long integer.
  6. Click OK.

Calculating the transparency level

  1. Right-click the layer or table you want to edit and click Open Attribute Table.
  2. Right-click the Xpar field heading that you want to make a calculation for and click Calculate Values.
  3. Click Yes when you see the dialog box. You can make calculations without being in an editing session; however, in that case, there is no way to undo the results.
  4. Use the Fields list and Functions to build a calculation expression. Enter this expression: 100-((100 * [distance])/36). This will calculate transparency values that are a function of the distance so that the buffers farther away are less transparent.
  5. Click Save.
  6. Name the calculate statement Xpar_values.cal. Click Save.
  7. Click OK.

Creating the universe polygon

Notice that you can see outside the extent of the last buffer. What you need to do to get rid of the rest of the image is to create one additional polygon in the buffers layer that will extend just outside the data frame. There are MANY ways to skin this cat — here is but one.  If you have others that work for you, share them with us in the Comments at the bottom.

Adding the Editor toolbar

  1. In ArcMap, click the View menu.
  2. Point to Toolbars.
  3. Click Editor. The toolbar is added.

Editing the buffer layer

  1. Click the Editor menu and click Start Editing.
  2. Choose the CA_buffer layer to edit it.
  3. Use the Zoom In tool on the Layout toolbar to zoom in closer to the data frame with the buffer in it.
  4. Use the Zoom In tool on the Standard toolbar to zoom in closer to the edges of the buffer layer.

Creating a polygon feature by digitizing

  1. Click the Current Task dropdown arrow and click Create New Feature.
  2. Click the Target layer dropdown arrow and click a line or polygon layer. This is the CA_buffer  layer.
  3. Click the Tool Palette dropdown arrow and click the Sketch tool.
  4. Click on the map to digitize the feature’s vertices. You want to create a polygon in the shape of a box with four vertices around the edge of the buffered state — get close to the edge of the data frame, and if you get a warning that you are out of bounds, just make the box a little smaller.
  5. When finished, right-click anywhere on the map and click Finish Sketch. The polygon is created on your map.

Now we will make the vertices to exact locations.

Moving a vertex by specifying x,y coordinates

  1. Click the Current Task dropdown arrow and click Modify Feature.
  2. Click the Edit tool and click the polygon you just digitized.
  3. Click to select the vertex you want to move. Start with the one in the upper left.
  4. Position the pointer over the vertex until the pointer changes.
  5. Right-click and click Move To.
  6. Type the x,y coordinates where you want to move the vertex. Use coordinates that are just outside the area of display for your map.
  7. Right-click any part of the sketch and click Finish Sketch. The feature is reshaped.

Calculating the transparency level of the universe polygon

  1. In the Table of Contents, right-click the CA_Buffer layer that you want to edit and click Open Attribute Table.
  2. Select the records for the polygon you just digitized.
  3. Right-click the field heading for the Xpar field that you want to change the value for.
  4. Type a value to set to the field. Use 0 (that’s zero!)
  5. Click Editor on the Editor toolbar and click Stop Editing.

Symbolizing the buffers

  1. Right-click the CA_Buffers layer that you want to draw with a single symbol in the Table of Contents and click Properties.
  2. Click the Symbology tab.
  3. Click Features. Because Single Symbol is the only option, ArcMap automatically selects it.
  4. Click the Symbol button to change the symbol. Select White.
  5. Click Outline color and select No color.
  6. Click OK on the Symbol Selector dialog box.
  7. Click Advanced. Click Transparency.
  8. Select Xpar as the field that you will use to vary the feature transparency based on field values in percent.
  9. Click OK.

Here are a couple more examples of what can be done with buffer vignette layers on coastlines:

Fade White - Figure 1

Above, the map background color is white and the buffers are blue.

Fade White - Figure 2

Here the map background color is blue and the buffers are white.

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Leave a Reply

5 Comments

  1. pakobalaban says:

    Dear Dr. Buckley,
    Great tip for cartographers, only one problem…
    Your steps regarding the universe polygon is wrong. the area of the map which we want the transparancy to be 100% should be cliped out from the universe polygon. with your steps it will simply cover the whole map and everything will look white….
    Thank you again for your tip….
    Pakrad

  2. lilrm01 says:

    Hi
    Having spent some time looking into this finishing touch I also believe that users of this site could benefit from a revised set of instructions under the following headings…

    Clipping the universe polygon

    1. Click the Editor menu and click Start Editing.
    2. Click the Editor menu and click Clip.
    3. Select the outermost buffer ring to clip universe polygon. Clip options: Buffer distance is 0 and discard the area that intersects.

    Symbolizing the buffers

    1. Right click the name of the buffer layer in the Table of Contents to see its properties.
    2. In the Layer Properties dialog under the Symbology tab, select Quantities then Graduated colors. Select field value: Xpar. Set the color for the buffer class farthest from land to the blue that will be used for the water outside the coastal area, and set the color for the class nearest to land to white.
    3. Click Outline color and select No color.
    4. Select the first and last classes together using the control key, then right-click on the color patch in the display and choose Ramp Colors. This applies a blue to
    white color ramp to all of the vector buffers using the two classes you specified as endpoints.
    5. Click OK on the Symbol Selector dialog box.
    6. Click Display. Set Transparency to suit e.g. 30%. Result will create a softer blend between buffer rings.
    7. Select Xpar as the field that you will use to vary the feature transparency based on field values in percent.
    8. Click OK.

    Hope it helps!

  3. abuckley says:

    I will update this blog entry soon and add a comment here to link to the new entry.

  4. guillaumephoenix says:

    Clear and useful. Thanks.