This post will cover two options dealing with map appearance: image type and map layers.
There are two image types possible for regular maps – street map and satellite imagery. In the Maps interface, these are controlled by a clickable box in the lower left which will say either “Satellite” or “Map” (it always shows the opposite of what is currently displayed). Technically, what Maps currently calls “Satellite” is more like Classic Maps’ “Hybrid” view, in that both satellite imagery and street map symbols are displayed; there does not appear to be any way to get a pure satellite image without map symbols.
Map view is set using option !3m1!1e0, although since this is the default setting it can be omitted. Satellite view is set using option !3m1!1e3. Multiple options are not possible; if you tried using !3m2!1e0!1e3 or !3m1!1e0!3m1!1e3, Maps would only apply the last one specified.
There are six different map layers that I have identified – traffic, transit, bicycling, terrain, images, and flights.
Layers are specified using the following format:
The layer values are:
2 = Transit (i.e., bus lines, light rail, etc)
3 = Bicycling (i.e., bike paths)
4 = Terrain
5 = Images (i.e., where Street View is available)
6 = Flights
So, if you wished to specify the terrain and traffic layers, the option set could look like:
Note that not all layers are compatible with each other. Traffic is not compatible with bicycling, transit, or images, and bicycling is also not compatible with transit or flights. If you specify a set of layers that includes one or more incompatibilities, Maps will resolve these from last to first, like this:
!1e3 is Bicycling – included
!1e1 is Traffic – incompatible with Bicycling; omitted
!1e2 is Transit – incompatible with Bicycling; omitted
!1e4 is Terrain – compatible with Bicycling; included
If multiple layers are specified in the URL, after resolving incompatibilities and rendering what it can, Maps will alter the URL to only include one layer (specifically, the last layer in the list which is not the Images layer) and will display the box on the left side which includes the options or notes for that layer.
There are two exceptions to the above rules that I have noticed.
- If the Bicycling and Flights layers are both specified, then even if the Bicycling layer comes after the Flights layer in the URL, Maps will not display the Bicycling layer. However, the layer box will still display the Bicycling layer information if that layer was last in the URL.
- If the Images layer is specified anywhere in the URL list and is not omitted due to compatibility rules, the layer box will show the Images layer information.
A few final notes:
- The Flights layer currently does not appear to display any flight-related information. It might need to be associated with personal flight information from the user’s Google+ account, or perhaps it is functionality that is under development; I just don’t know.
- Transit will display transit routes but only in limited areas; apparently not much transit information is available in the Google Maps system at this time.
- There is apparently no way to specify a day and time for the Traffic layer; only live traffic is available via the URL. You can, of course, select “Typical Traffic” in the Maps interface, but if you had more than one layer up the non-traffic layer(s) will be lost when you do this.