Adds points interactively to a spatial point pattern (M.A. Mugglestone, S.A. Harding, B.Y.Y. Lee, P.J. Diggle & B.S. Rowlingson).

### Options

`PRINT` = string token |
What to print (`summary` , `monitoring` ); default `summ` , `moni` |
---|---|

`WINDOW` = scalar |
Which graphics window to use for the plot; default 1 |

### Parameters

`OLDY` = variates |
Vertical coordinates of each spatial point pattern; no default – this parameter must be set |
---|---|

`OLDY` = variates |
Horizontal coordinates of each spatial point pattern; no default – this parameter must be set |

`NEWY` = variates |
Variates to receive the vertical coordinates of the original points and added points |

`NEWX` = variates |
Variates to receive the horizontal coordinates of the original points and added points |

### Description

`DPTREAD`

uses the `DREAD`

directive to add points to a spatial point pattern. The coordinates of the existing points must be supplied using the parameters `OLDX`

and `OLDY`

. These points will be plotted on the current graphics device using `DPTMAP`

with a pen setting of `SYMBOLS=1`

. The `WINDOW`

option may be used to specify the graphics window to use for the plot.

`DREAD`

is not always available, and its operation may vary slightly from one system to another. The Users’ Note supplied with Genstat explains how to read points and terminate input on specific devices. The usual method for reading points is to click the left mouse button at the required position. The usual way to terminate input is to click the right mouse button. The points read using `DREAD`

will be echoed using a pen setting of `SYMBOLS=2`

. The coordinates of the new spatial point pattern containing the original points and any points which have been added may be saved using the parameters `NEWX`

and `NEWY`

.

Printed output is controlled using the `PRINT`

option. The settings available are `monitoring`

(which prints the coordinates of the points to be added) and `summary`

(which prints the coordinates of the new pattern consisting of the original points and any that have been added under the headingss `NEWX`

and `NEWY`

). The default setting is for both `monitoring`

and `summary`

.

Options: `PRINT`

, `WINDOW`

.

Parameters: `OLDY`

, `OLDX`

, `NEWY`

, `NEWX`

.

### Method

A procedure `PTCHECKXY`

is called to check that `OLDX`

and `OLDY`

have identical restrictions. `DPTMAP`

is used to draw a map of the original point pattern. The `DREAD`

directive is then used to read the coordinates of points to be added. Finally, the coordinates for the original points and added points are combined in new variates using the `EQUATE`

directive.

### Action with `RESTRICT`

If `OLDX`

and `OLDY`

are restricted, only the subset of values specified by the restriction will be included in the calculations.

### See also

Procedure: `DRPOLYGON`

.

Commands for: Graphics, Spatial statistics.

### See also

Procedure: `DRPOLYGON`

, `PTREMOVE`

.

Commands for: Graphics, Spatial statistics.

### Example

CAPTION 'DPTREAD example'; STYLE=meta CALCULATE x,y = URAND(347659,0; 50) DPTREAD OLDY=y; OLDX=x