closestBoundary

Get nearest boundary to location

Since R2023a

Syntax

boundary = closestBoundary(map)

boundary = closestBoundary(map,location)

boundary = closestBoundary(map,location,frame)

[boundary,isValid] = closestBoundary(map,location,___)

boundary = closestBoundary(map,cornerLocation,matSize)

boundary = closestBoundary(map,cornerLocation,matSize,frame)

Description

boundary = closestBoundary(map) returns the locations of the closest obstacles boundary for each cell of the specified signed distance map map.

boundary = closestBoundary(map,location) returns the closest boundary locations for the specified xy-locations locations in world coordinates.

boundary = closestBoundary(map,location,frame) returns the closest boundary locations for the specified locations locations in the coordinate frame frame.

[boundary,isValid] = closestBoundary(map,location,___) returns isValid, indicating which of the specified locations locations are within the map bounds.

boundary = closestBoundary(map,cornerLocation,matSize) returns the closest boundary locations for a subregion of the signed distance map, map. The subregion starts in the minimum corner location cornerLocation in the world coordinate frame with a given map size matSize.

boundary = closestBoundary(map,cornerLocation,matSize,frame) returns the closest boundary locations for a subregion of the signed distance map, map. The subregion starts in the minimum corner location cornerLocation in the coordinate frame frame.

Note

When specifying a corner location and map size, closestBoundary determines the closest boundary locations using the distances between cell centers within the rectangular query region.

Examples

Find Closest Boundary in Signed Distance Map

Create a signed distance map with a width of 40 cells and a height of 20 cells.

map = signedDistanceMap(40,20);

Update the map occupancy with an identity matrix.

setMapData(map,[1 10],eye(20),"grid");
show(map);

Find nearest boundary for each corner cell of map.

queryIJ = [1 1; 20 1; 1 40; 20 40];
nearestCornerIJ = closestBoundary(map,queryIJ,"grid")

nearestCornerIJ = 
nearestCornerIJ(:,:,1) =

     1
     6
    16
    20


nearestCornerIJ(:,:,2) =

    10
    15
    25
    29

Find nearest XY boundary cell for cells in the first 5-by-5 quadrant in the top-left.

nearestQuadrantXY = closestBoundary(map,[0 5],[5 5])

nearestQuadrantXY = 
nearestQuadrantXY(:,:,1) =

    9.5000   10.5000   10.5000   11.5000   11.5000
   10.5000   10.5000   11.5000   11.5000   12.5000
   10.5000   11.5000   11.5000   12.5000   12.5000
   11.5000   11.5000   12.5000   12.5000   13.5000
   11.5000   12.5000   12.5000   13.5000   13.5000


nearestQuadrantXY(:,:,2) =

   19.5000   18.5000   18.5000   17.5000   17.5000
   18.5000   18.5000   17.5000   17.5000   16.5000
   18.5000   17.5000   17.5000   16.5000   16.5000
   17.5000   17.5000   16.5000   16.5000   15.5000
   17.5000   16.5000   16.5000   15.5000   15.5000

Input Arguments

map — Signed distance map

signedDistanceMap object

Signed distance map, specified as a signedDistanceMap object.

location — World or local coordinates, or grid locations

N-by-2 matrix

World or local coordinates, or grid locations, specified as an N-by-2 matrix. N is the number of locations. The format of the rows depends on the value of the frame argument:

• "world" — [x y] coordinates in the world frame.

• "local" — [x y] coordinates in the local frame.

• "grid" — [row column] location in the grid frame.

cornerLocation — Minimum corner location of output matrix

two-element vector

Minimum corner location of output matrix, specified as a two-element vector of coordinates in the form, [x y]. The location is in world or local coordinates if the frame argument is set to "world" and "local", respectively. When frame is "grid", the coordinates are in the form [row column] and cornerLocation is the top-left corner of the world frame.

matSize — Subregion map size

two-element vector | [x y]

Subregion map size, specified as a two-element vector [x y] in world or local coordinates. Location is in world or local coordinates if the frame argument is set to "world" and "local", respectively. When frame is "grid", cornerLocation is the top-left corner of the world frame.

frame — Coordinate frame

"world" (default) | "local" | "grid"

Coordinate frame, specified as one of these options:

• "world" — Specify coordinates in the world frame.

• "local" — Specify coordinates in the local frame.

• "grid" — Specify grid locations in the grid frame.

Data Types: char | string

Output Arguments

boundary — Nearest boundary point

L-by-1-by-2 array | M-by-N-by-2 array

Nearest boundary point, returned as an L-by-1-by-2 array for point queries and an M-by-N-by-2 array for subregion queries. L is the number of locations queried. M and N are the dimensions of the map or specified map subregion.

isValid — Points in boundary

L-element vector

Points in boundary, returned as an L-element vector, where L is the total number of queried locations. Each element is a 1 (true) if the point is within the boundaries, and 0 (false) if the point is outside boundaries.

This output is only returned for point queries.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2023a