Plots circular data (P.W. Goedhart & R.W. Payne).

### Options

`PLOT` = string tokens |
Information to be plotted (`counts` , `kerneldensity` , `lines` , `mean` , `rose` ); default `coun` , `mean` , `rose` |
---|---|

`TITLE` = text |
Title for the graph; default `*` i.e. none |

`SEGMENT` = scalar |
Width of sectors (in degrees) into which to group an `ANGLES` variates before plotting; default 20 |

`MSEGMENT` = scalar |
Defines the centre (in degrees) of the sectors; default 0 |

`BANDWIDTH` = scalar |
Bandwidth to use for the kernel density estimate; if this is unset, the value h_{0} suggested by Fisher (1993, page 26) is used |

`NGRID` = scalar |
Defines the number of grid points for the kernel density estimate; default 180 |

`WINDOW` = scalar |
Window for the graph; default 3 |

`SCREEN` = string token |
Whether to clear screen before displaying the graph (`keep` , `clear` ); default `clea` |

### Parameters

`ANGLES` = factors or variates |
Directional observations to be plotted |
---|---|

`GRID` = variates |
Saves the grid (in degrees) on which the kernel density is estimated |

`DENSITY` = variates |
Saves the kernel density estimate |

`SAVEBANDWIDTH` = scalar |
Saves the calculated bandwidth h_{0} when `BANDWIDTH` is unset |

### Description

`DCIRCULAR`

plots data values that consist of directional observations recorded as angles between 0 and 360 degrees. The data values are supplied by the `ANGLES`

parameter, in either a variate or a factor. With a variate, the observations are grouped for plotting into sectors of width specified (in degrees) by the `SEGMENT`

option, with centres defined by the `MSEGMENT`

option. The sectors are centred at `MSEGMENT`

, `MSEGMENT+SEGMENT`

, `MSEGMENT+2*SEGMENT`

, and so on. The default value for `SEGMENT`

and `MSEGMENT`

is 20 and 0 respectively. If `ANGLES`

is set to a factor, its levels define the midpoints of the sectors and these must be in clockwise order.

The graph contains a circle with marks at every 10 degrees, and labels at 0, 90, 180 and 270 degrees. The representations of the observations are determined by the settings supplied for the `PLOT`

option as follows

By default `PLOT=counts,mean,rose`

.

The options `TITLE`

, `WINDOW`

and `SCREEN`

allow you to define a title for the plot, specify which window to use, and indicate whether or not to clear the screen beforehand. Parameters `GRID`

, `DENSITY`

and `SAVEBANDWIDTH`

can be used to save the grid (in degrees), kernel estimate and bandwidth h_{0}. The latter is saved only when `BANDWIDTH`

is unset.

Options: `PLOT`

, `TITLE`

, `SEGMENT`

, `MSEGMENT`

, `BANDWIDTH`

, `NGRID`

, `WINDOW`

, `SCREEN`

.

Parameters: `ANGLES`

, `GRID`

, `DENSITY`

, `SAVEBANDWIDTH`

.

### Method

`DCIRCULAR`

uses Genstat’s standard graphics and calculation commands. The underlying methodology is described by Fisher (1993).

### Action with `RESTRICT`

If `ANGLES`

is restricted, only the unrestricted units are plotted.

### Reference

Fisher, N.I. (1993). *Statistical Analysis of Circular Data*. Cambridge University Press, Cambridge.

### See also

Procedures: `CASSOCIATION`

, `CCOMPARE`

, `CDESCRIBE`

, `DYPOLAR`

, `RCIRCULAR`

, `WINDROSE`

.

Commands for: Graphics.

### Example

CAPTION 'DCIRCULAR example',!t(\ 'Directions chosen by 100 ants in response to an evenly illuminated',\ 'black target placed at 180 degrees (see Fisher 1993, page 61).');\ STYLE=meta,plain VARIATE [NVALUES=100] Direction READ Direction 330 290 60 200 200 180 280 220 190 180 180 160 280 180 170 190 180 140 150 150 160 200 190 250 180 30 200 180 200 350 200 180 120 200 210 130 30 210 200 230 180 160 210 190 180 230 50 150 210 180 190 210 220 200 60 260 110 180 220 170 10 220 180 210 170 90 160 180 170 200 160 180 120 150 300 190 220 160 70 190 110 270 180 200 180 140 360 150 160 170 140 40 300 80 210 200 170 200 210 190 : DCIRCULAR [TITLE='Directions chosen by 100 ants.'] Direction