Ask A Cartographer

Aerial Photo Map Design

March 04 2010 | 0 comments
Categories: Cartographic Design, Labeling, Symbology

Do you have any design suggestions for creating maps that show aerial photos as a background? Frequently we are asked to create maps that include contours, roads, parcels, and trails with an aerial photo background. Do you have any suggestions for colors, transparency, and styles that combines all these elements together into a nice readable map?

Thanks

Mapping Center Answer:

Here are some recommendations for labeling and symbology on image maps.

Labeling:

Labeling features on an image map is challenging because the image itself can have so many different colors. Therefore, the trick is to design your labels in such a way that they can be seen no matter what is in the background. In essence, you need to bring the labels to the foreground of the map.

In popular commercial online map services, you see a common pattern for labeling. The labels use a variation in hue depending on what feature they represent (park labels-green, street labels-white, cultural feature labels-pink, etc.), but the background mask (or halo) of the label is typically black or another dark color. The problem with this combination is that when the labels are placed on an area of the image that is predominantly dark, the overall legibility of the label is compromised.

With that said, there are a couple of things to consider when designing your labels:

  1. The font: We recommend that you use not only a san serif font, but one that has round edges at the ends of the letters. The reason is because often times, you use a halo around your text on image maps. If each letter has round edges, the halo fits around the text better which increases legibility.
  2. Colors: What I have found most effective is to use a bright color (higher in saturation) for the label and a darker version of the same color (lower in value) for the halo. This really helps the text pop out. And the size of the halo doesn't have to be too big. Actually, you want it to fit as tightly as possible around the text so you aren't obstructing the view of the image around the label. However, check the halo size to make sure that the counters (open spaces in the letters themselves) are still filled in.

Symbology:

In your example, you are symbolizing roads and contours. One of the first things I notice is the difficulty in seeing the imagery, and hence, the information below the contours and the roads.

Because imagery already has so much detail, we don't want to add too much extra detail to the map. You can still symbolize your roads by type using color and size, but instead of orange you might try white or a light gray (for minor roads) and instead of pink, you might try yellow or orange (for major roads). I would also recommend that you apply transparency to the roads so the underlying information from the image is still visible. You can try a similar approach with your contour lines. Try using a thinner line weight and applying transparency.

Some other resources that you may find useful are:

If you would like to post a comment, please login.

Contact Us | Legal | Privacy |