nearestvertex

Query nearest polyshape vertex

Syntax

[vertexid,boundaryid,ind] = nearestvertex(polyin,x,y)

[vertexid,boundaryid,ind] = nearestvertex(polyin,P)

Description

[vertexid,boundaryid,ind] = nearestvertex(polyin,x,y) finds the vertex of a scalar polyshape object that is nearest to each 2-D query point. The coordinates of the query points are specified in x and y. The output contains three vectors:

• vertexid contains the row number in polyin.Vertices corresponding to the nearest vertex for each query point.

• boundaryid contains the boundary index of polyin corresponding to the nearest vertex for each query point.

• ind contains the nearest vertex index in the boundary boundaryid for each query point.

[vertexid,boundaryid,ind] = nearestvertex(polyin,P) specifies the query points as a 2-column matrix P whose first column contains the x-coordinates and whose second column contains the corresponding y-coordinates.

Examples

Nearest Vertex

Create a polyshape object and compute the nearest vertex of the polyshape to the query point (2,1.8).

P = [1 1; 3 1; 2 2];
polyin = polyshape(P);
[vertexid,boundaryid,ind] = nearestvertex(polyin,2,1.8);

Plot the polyshape and the query point in black.

plot(polyin)
hold on
plot(2,2.5,'k*')

Now plot the nearest vertex in red. The vertexid value enables you to index into the row of polyin.Vertices corresponding to the nearest vertex, accessing its coordinates.

plot(polyin.Vertices(vertexid,1),polyin.Vertices(vertexid,2),'r*')
hold off

Input Arguments

polyin — Input polyshape

scalar

Input polyshape, specified as a scalar polyshape object.

x,y — Input coordinates

scalars | vectors

Input coordinates of 2-D query points, specified as scalars or vectors. x and y must have the same length.

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

P — Input vertices

2-column matrix

Input vertices of 2-D query points, specified as a 2-column matrix. The first column of P contains the x-coordinates and the second column contains the corresponding y-coordinates.

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

Output Arguments

vertexid — Vertex ID

scalar | vector

Vertex ID, returned as a scalar or vector. vertexid contains the row number in the input polyshape corresponding to the nearest vertex for each query point. vertexid is the same length as the query point vectors or array.

Data Types: double

boundaryid — Boundary ID

scalar | vector

Boundary ID, returned as a scalar or vector. boundaryid contains the boundary index of the input polyshape corresponding to the nearest vertex for each query point. boundaryid is the same length as the query point vectors or array.

Data Types: double

ind — Index

scalar | vector

Index, returned as a scalar or vector. ind contains the nearest vertex index in the boundary boundaryid for each query point.

Data Types: double

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• Dynamic memory allocation must be enabled for code generation.

Version History

Introduced in R2018a