DPTREAD procedure

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
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.