XploRe Help : SPKRmultcontours

Keywords - Function groups - @ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Library:	spatial
See also:	SPKRsurfls SPKRsurfgls SPKRexpcov SPKRgaucov SPKRsphercov SPKRtrmat SPKRprmat SPKRsemat SPKRcorrelogram SPKRvariogram

Quantlet:		SPKRmultcontours
Description:		draws multiple contour lines of a spatial object of type "trmat", "prmat", or "semat"

Reference(s):

Venables, W. N., Ripley, B. D. (1999): Modern Applied Statistics with S-Plus, Third Edition, Springer, New York

Link:

Tutorial: Spatial statistics

Usage:	`res = SPKRmultcontours(disp, pos1, pos2, obj, start, end, step)`
Input:
	`disp`	display, in which the contour lines should be shown
	`pos1`	scalar, row of the display
	`pos2`	scalar, column of the display
	`obj`	list, (of type "trmat", "prmat", or "semat") calculated by SPKRtrmat, SPKRprmat, or SPKRsemat
	`start`	scalar, starting value for contour lines
	`end`	scalar, ending value for contour lines
	`step`	scalar, step width between two contour lines
Output:
	`res`	n x 2 matrix, contains all points at all levels of the contour lines

Example:

; loads the spatial statistics library library("spatial") ; reads a spatial data set topo = read("topo.dat") ; calculates a polynomial regression surface of order 2 myres = SPKRsurfls(2, topo) ; calculates a 30 x 30 grid within [0, 6.5] x [0, 6.5] ; using trend surface myres mygrid = SPKRtrmat(myres, 0, 6.5, 0, 6.5, 30) ; creates a display and draws contour lines in the range ; 750 through 975, using steps of width 25 disp = createdisplay(1, 1) cont = SPKRmultcontours(disp, 1, 1, mygrid, 750, 975, 25)

Result:

A plot of multiple countour lines is drawn and the
corresponding points are returned.

Author: J. Symanzik, 20000725 license MD*Tech