Overlay Description Format
Overlay maps are described in a JSON formatted file. When you submit an overlay file, they are compiled into Platform Data Extension API layers and stored as a separate map with the layers containing the map changes.
Contents of an Overlay Description File
An overlay description file consists of a JSON array with JSON objects. Each JSON object describes a single map modification operation.
opfield is a mandatory field that specifies the type of operation:
op : create– Creates a new road link
op : override– Changes the attribute values of an existing link attribute (such as allowed vehicle types), or add a restriction (condition) to a link (like a truck weight limit).
The other fields of an operation are specified below.
Overlay Create Object
You can create a new link between two existing links. Currently, you can specify the link geometry and their corresponding attributes. All other link attributes are copied from an existing neighboring link. The existing links are always cut at the point where the new link is inserted.
shape– An array of shape points where each shape point is an array of two elements, latitude and longitude, in WGS-84 degree
Currently, the first and last point must each fit within 5 meters tolerance onto existing links. These points must not both end up on the same link.
layer– The Platform Data Extension API layer, in which to insert the link or new restrictions
Currently, only the LINK_ATTRIBUTE_FCN layer is supported.
data– The map of attribute/value pairs
Currently only VEHICLE_TYPE and TRAVEL_DIRECTION are supported. For more information on Layers, Indexes, and Attributes see the Platform Data Extension API documentation.
Overlay Override Object
shape– An array of shape points where each shape point is an array of two elements, latitude and longitude, in WGS-84 degree. The geometry must be an approximate match of the existing link's geometry; shape points can be ommitted. If the geometry denotes a path of several connected links in the map, then the attributes of all these links are changed.
layer– The Platform Data Extension API layer in which the link attributes need to be changed. Currently, the LINK_ATTRIBUTE_FCN and TRUCK_RESTR_FCN layers are supported.
data– The map of attribute/value pairs. Currently, for layer LINK_ATTRIBUTE_FCN, only VEHICLE_TYPE and TRAVEL_DIRECTION are supported. For layer TRUCK_RESTR_FCN, the attributes VEHICLE_TYPES, WEIGHT_RESTRICTION, HEIGHT_RESTRICTION, LENGTH_RESTRICTION, WIDTH_RESTRICTION, MAX_WEIGHT_PER_AXLE, NUMBER_OF_AXLES, KPRA_LENGTH, HAZARDOUS_MATERIAL_TYPE, HAZMAT_PERMIT_REQUIRED are supported. For more information on Layers, Indexes, and Attributes see the Platform Data Extension API documentation.