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CostMap2D

Description

The Cost Map 2D Service provides a mechanism to report obstacles, hazardous terrain, and no-go zones using an overhead 2D cost map. The cost map is represented by a list of cells, broken into a specified number of rows and columns, which in turn corresponds to the width and height (respectively) of the map in meters. Each cell within the map specifies a cost value, and in some cases, a confidence value. The cost is a relative measure of occupancy or effort to traverse the cell, such that a value of zero (0) means no occupancy or no effort, while a maximum cost value means a cell is non-traversable. The center point of the cost map may be specified in global or local coordinates, depending on the particular implementation, as defined by [AS6009]. The map may also be rotated around the coordinate frame's Z-axis by the specified rotation value. Cells within the list must be sequenced such that the most northwest point (i.e. most forward left), relative to the non-rotated coordinate frame, is the first element. Subsequent elements represent cells in an easterly direction, until the end of the row is reached. At that point, the next row starts again on the west side of the map. * DIAGRAM HERE * To add support for client-specified no-go (exclusion) zones, this service should be co-located (hosted on the same component) as the Global or Local Operating Zone Service. Note that the cost of each cell is described across a range providing a low value (no cost, free cell) and a high cost (no-go, lethal cell). The interpretation of these values, as well as values in between, is not defined by the Standard, as it is expected to be vehicle- and implementation-specific. As a result, users are cautioned against using these values across multiple systems. For example, what may be considered high cost for a small, low traction ground vehicle may be trivial to a larger, more capable system.

Messages

The CostMap2D service uses the following messages.

Internal Events

  • None