Placing labels on maps is a hard problem. Although quite a bit of work has been done on how to place labels so that they don’t overlap, not much work has been done on how to place labels in an aesthetically pleasing manner. In an effort to understand what’s in production already I decided to make a brief comparison of Google Maps and Microsoft’s Live Maps.

The two maps compared are for the Redmond, Washington area where I lived for the past year. You can compare them yourself by opening Google’s and Microsoft’s versions of the same area. I was looking at them on a relatively large monitor, so you may need to scroll around a little bit to see the same things.

1. Initial Impressions. Microsoft uses a subdued color scheme which reminds me of Eduard Imhof’s maps. The parks could be slightly greener, but otherwise it’s very nice. Google’s color scheme is more saturated and, to my eye, not as clean. On the other hand, Microsoft’s map is noticeably blurry, apparently caused by too much anti-aliasing. The small, unlabeled roads in Google are too strong, they distract from the rest of the map. The unlabeled roads in Microsoft are lighter which looks better. However, some of their labeled roads are also very light! It’s often unclear with which street the label is associated. As a general rule: if the street is labeled it should be dark, if not, it should be very light or not rendered at all.
2. Label Selection. One of the most noticeable differences is the types of labels shown at this zoom level. Microsoft labels a lot of streets, but only one park out of dozens. Google’s map labels almost all the parks and only labels the largest streets. Park names are useful as landmarks, but it they can’t be nearly as useful as street names. Why waste screen space on them?
3. Label Clutter. Since Microsoft shows so many street labels, it can suffer from unsightly cluttering, although labels never actually overlap. Notice how the meeting of “NE 85th St” and “116th Ave NE” at right angles looks awkward. Also the coincidence of the top of the ‘E’ in “124th Ave NE” with the edge of the freeway is distracting. Also notice the lack of any alignment and the seeming arbitrary top-to-bottom vs. bottom-to-top reading of the vertical text.
4. Label Layout. Microsoft seems inconsistent in placing street labels adjacent to or directly over the road. Google always places the text over the street.
5. Text Layout. In both maps, the street label text follows the path of the street. This leads to some very strange text, especially on Microsoft’s map. “Sammamish” is really one word. An obvious solution would be to smooth the path so this doesn’t happen. The rotation and baseline of a label’s text should change smoothly over the label. A related problem is that of character spacing. Notice that the ‘i’ has almost disappeared from the word “Sammamish”.
6. Label Contrast. Both maps render a background behind the text to make the label stand out from the map. Google’s is a nearly opaque white border (or yellow, for main roads). Microsoft uses a much more subtle mask. Visually, I prefer Microsoft’s approach. However, I did notice that in many places Microsoft’s mask would obscure the road, making the label appear unassociated with anything on the map. Google neatly avoids this problem by making the text border the same color as the road (yellow), this provides more visual continuity to the road even when obscured by the label.
7. Labeling Areas. Labeling of areas doesn’t work very well as you zoom into the area. For example, city labels remain even after you have zoomed so that the city fills up almost the entire screen. It appears that the city label is identifying a specific intersection, rather than an entire area. I’d be interested to see how traditional maps deal with this problem.