ginput

Identify axes coordinates

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Syntax

[x,y] = ginput(n)
[x,y] = ginput
[x,y,button] = ginput(___)

Description

example

[x,y] = ginput(n) allows you to identify the coordinates of n points. To choose a point, move your cursor to the desired location and press either a mouse button or a key on the keyboard. Press the Return key to stop before all n points are selected. MATLAB® returns the coordinates of your selected points. If there are no current axes, calling ginput creates a set of Cartesian axes.

example

[x,y] = ginput allows you to select an unlimited number of points until you press the Return key.

example

[x,y,button] = ginput(___) also returns the mouse button or key on the keyboard used to select each point.

Examples

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Identify four points in a set of axes using ginput. To select each point, move the cursor to your desired location and press a mouse button or key.

[x,y] = ginput(4)

x =

    0.3699
    0.4425
    0.5450
    0.6130


y =

    0.6690
    0.5605
    0.4719
    0.6025

Plot the points.

plot(x,y);

Identify five coordinates in a set of axes using ginput. To select each point, move the cursor to your desired location and press a mouse button, lowercase letter, uppercase letter, number, or the space bar. Return the mouse buttons or ASCII numbers of the keys used to select each point.

[x,y,button] = ginput(5);
button

button =

     3
   104
    32
    51
    82

In this case, the coordinates were identified using the right mouse button (3), the lowercase letter h (104), the space bar (32), the number 3 (51), and the uppercase letter R (82).

Create geographic axes and identify the latitude and longitude coordinates of four points. Then, plot the points that you identify.

geoaxes
[lat,lon] = ginput(4);

Use the hold on command and the geolimits function to maintain the map limits. Plot the identified points.

hold on
geolimits('manual')
geoscatter(lat,lon,'filled','b')

Input Arguments

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Number of points to identify, specified as a positive integer.

Output Arguments

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First components of the identified coordinates, returned as a scalar or column vector.

  • If the current axes are Cartesian, the values are x-coordinates.

  • If the current axes are geographic, the values are latitudes. Positive values correspond to north and negative values correspond to south.

If you choose points outside the axes limits, values are still returned relative to the axes origin.

Second components of the identified coordinates, returned as a scalar or column vector.

  • If the current axes are Cartesian, the values are y-coordinates.

  • If the current axes are geographic, the values are longitudes. Positive values correspond to locations east of the origin and negative values correspond to locations west of the origin.

If you choose points outside the axes limits, values are still returned relative to the axes origin.

Keys or mouse buttons used to identify points, returned as a scalar or column vector. Mouse buttons are indicated by 1 for the left button, 2 for the middle, and 3 for the right. Double-clicks are indicated by two values. The first value is 1 for the left mouse button, 2 for the middle, and 3 for the right. The second value is 1.

Keys on the keyboard are indicated by their corresponding ASCII numbers. Taps on a screen are indicated by 1.

For example, call ginput, click using the middle mouse button, double-click using the right mouse button, and then press Enter. The output button is a vector containing 2, 3, and 1.

[~,~,button] = ginput
button =

     2
     3
     1

See Also

Functions

Introduced before R2006a

MATLAB Documentation

Support