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closestBoundary

Get nearest boundary to location

Since R2023a

    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.

    example

    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

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    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

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    Signed distance map, specified as a signedDistanceMap object.

    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.

    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.

    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.

    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

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    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.

    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