centroid

Centroid of polyshape

collapse all in page

Syntax

[x,y] = centroid(polyin)
[x,y] = centroid(polyin,I)

Description

example

[x,y] = centroid(polyin) returns the x-coordinates and the y-coordinates of the centroid of a polyshape.

example

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

This syntax is only supported when polyin is a scalar polyshape object.

Examples

collapse all

Open Live Script

Compute the centroids associated with a multiregion polygon.

Create a polygon containing two solid regions, and then compute its centroid. 

x1 = [0 1 2];
y1 = [0 1 0];
x2 = [2 3 4];
y2 = [1 2 1];
polyin = polyshape({x1,x2},{y1,y2});
[x,y] = centroid(polyin);
plot(polyin)
hold on
plot(x,y,'r*')
hold off

To compute the centroid of each region separately, specify the boundary indices of each region in the second argument.

[x,y] = centroid(polyin,[1 2]);
plot(polyin)
hold on
plot(x(1),y(1),'r*',x(2),y(2),'r*')
hold off

Alternatively, you can compute the centroid of each region by first separating the regions into separate polyshape objects. Use the regions function to create an array of polyshape objects, where each element of the array is a polyshape defining one of the triangular regions.

polyarray = regions(polyin)
polyarray = 
  2x1 polyshape array with properties:

    Vertices
    NumRegions
    NumHoles


[x,y] = centroid(polyarray)
x = 2×1

     1
     3


y = 2×1

    0.3333
    1.3333


Input Arguments
collapse all

                    
Input polyshape, specified as a scalar, vector, matrix,
                        or multidimensional array.

                
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
collapse all

                    
x-coordinate of the centroid of a
                            polyshape, returned as a scalar, vector, matrix, or
                        multidimensional array. If the input is an array of
                            polyshape objects, then x contains
                        the x-coordinates of the centroid of each
                            polyshape.

                

                    
y-coordinate of the centroid of a
                            polyshape, returned as a scalar, vector, matrix, or
                        multidimensional array. If the input is an array of
                            polyshape objects, then y contains
                        the y-coordinates of the centroid of each
                            polyshape.

                
See Also
 |  | 
Introduced in R2017b

    




























MATLAB Documentation





Support