DriveWorks SDK Reference
3.5.78 Release
For Test and Development only

Map Query
SW Release Applicability: This tutorial is applicable to modules in NVIDIA DRIVE Software releases.

Result Buffers

Maps module functions that return an array of elements write the returned elements into a fixed size buffer that is passed in as an argument. There are Buffer structs for various map elements:

A Buffer struct must be initialized before being passed to the function:

  • buffer: pointer to the fixed size array
  • maxSize: size of the fixed size array
  • size: current number of valid elements in the array

Query Functions

Road Segments

Road Segments provide access to all the map data.

The dwMaps_getRoadSegments() function returns copies of Road Segments that overlap with a bounding box of longitude and latitude coordinates.

To retrieve pointers to Road Segments owned by the system instead use dwMaps_getRoadSegmentPointers(). This has the advantage of reduced memory footprint vs creating copies of dwMapsRoadSegment.

For convenience, there are a few more specific query functions:

Lane Dividers

dwMapsLaneDividerBuffer* laneDividers,
uint32_t typeFilter,
const dwMapsBounds* bounds,
dwConstMapHandle_t mapHandle);

dwMaps_getLaneDividers() returns all Lane Dividers that overlap with a bounding box of longitude and latitude coordinates, filtered by their type. A logical combination of type flags can be used to specify which Lane Dividers are returned.


uint32_t typeFilter,
const dwMapsBounds* bounds,
dwConstMapHandle_t mapHandle);

dwMaps_getFeatures() works the same way as dwMaps_getLaneDividers().

Closest Lane

dwStatus dwMaps_getClosestLane(
const dwMapsLane** closestLane,
dwMapsGeoPoint* closestPoint,
const dwMapsGeoPoint* p,
dwBool onlyDrivable,
dwBool ignoreHeight,
dwConstMapHandle_t mapHandle);

dwMaps_getClosestLane() returns the closest Lane, and the closest point on it, to a given query point p. When the onlyDrivable flag is set to true, non-drivable lanes are not considered. ignoreHeight can be set if the height of the input point is unknown or inaccurate. In that case, the distances are compared, after projecting all points to height 0.

The maps module also provides a map tracker that allows a robust selection of the current lane when driving along a road. It also incorporates orientation and logical connections and thus can give a better result than just picking the closest lane.

For more information see Map Access Sample .