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boundary

Vertex coordinates of polyshape boundary

Description

example

[x,y] = boundary(polyin) returns the x-coordinates and the y-coordinates of each boundary of a polyshape. The vectors x and y contain the list of coordinates for each boundary, delimited by NaN. The boundary function automatically appends the first vertex coordinates of polyin to the end of x and y to close the polygon.

[x,y] = boundary(polyin,I) returns the coordinates of the Ith boundary of a polyshape.

Examples

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Create a polygon containing two boundaries, and display the vertex coordinates of both boundaries. The list of vertices for the boundaries are delimited by NaN.

x1 = [0 1 2];
y1 = [0 1 0];
x2 = [2 3 4];
y2 = [1 2 1];
polyin = polyshape({x1,x2},{y1,y2});
plot(polyin)

[x,y] = boundary(polyin)
x = 9×1

     0
     1
     2
     0
   NaN
     2
     3
     4
     2

y = 9×1

     0
     1
     0
     0
   NaN
     1
     2
     1
     1

Input Arguments

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Input polyshape, specified as a scalar.

Data Types: polyshape

Boundary index, specified as a scalar integer or vector of integers. Each element of I corresponds to a single boundary of the input polyshape.

Data Types: double | single | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Output Arguments

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x-coordinates of polyshape boundaries, returned as a column vector. When returning multiple boundaries, boundary places NaN values between each boundary's set of coordinates.

Data Types: double

y-coordinates of polyshape boundary, returned as a column vector. When returning multiple boundaries, boundary places NaN values between each boundary's set of coordinates.

Data Types: double

Introduced in R2017b