Waze map editors use the term basemap to refer to roads imported from external sources that have never been edited and for areas that contain them.
Background
A basemap (or base map) is a collection of reference data intended to provide visual orientation to users of a map, so that further details can be added and displayed on it in a meaningful way. It may include data on imagery, topography, roads, political boundaries or other things, depending on the purpose of the map. In many countries, Waze has licensed and imported data on roads and other features from various sources to serve as its basemap, and this is the foundation upon which users and map editors build to create a usable navigation system.
Depending on the data source used to import roads for each particular country, basemap roads require various updates from map editors in order to provide efficient navigation and useful display. This can involve confirming directions, turns, and names, adjusting geometry and connectivity, removing extraneous nodes and segments and setting road types, locks, elevations and other road attributes. Because they require specifial cleanup from editors, and because they contain unique features relative to roads created and edited by users, map editors often refer to these unedited roads and areas that contain them simply as basemap.
Basemap roads in the United States
Waze imported TIGER data from the US Census Bureau to serve as its basemap in January, 2009. TIGER data provided somewhat accurate names, locations and cities/states for roads, but it did not include road directions, allowed turns, distinctions between road types beyond Street , Private Road or Unpaved , or any navigation history. Because this data was designed for location of people and places and not for navigation, it contained many odd angles and extraneous geometry and junction nodes when added to the Waze map.
Basemap roads in the USA have unknown direction and soft restricted turns by default, but Waze is designed so that users add data to roads as they drive over them. When enough users drive over a road of unknown direction from node A to node B onto another segment, Waze will automatically set the direction to one way (A→B) and will set the turn from node B onto the other segment to soft enabled. If enough users drive from B to A on this same segment, Waze will then set the road to two way, but the turns will still be unconfirmed. These directions and turns remain guesses and are affected by various routing penalties until set by an editor. Once a segment is edited and its turns are confirmed, penalties no longer apply to enabled turns, and any restricted turns and forbidden directions become absolute and will not be routed.
Editing basemap roads
It's easy to tell when the basemap roads were imported in an area, because most road segments will have the same creation date. If a road segment has that date but does not have an updated date listed in its information, it is an unedited basemap road that needs to be updated. Additionally, features like unknown direction, unconfirmed turns, excess nodes and segments that don't match imagery are clues that a road has not been edited much from its basemap state, even if it has been updated by someone. Editors should watch for and fix the following things when editing basemap roads: