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DCL:GRPH2:UDPACK: Contour Routines: Explanation of Subroutines

8.2.8 RUDLEV

1.

Function

Determines the interval of the contour level set by UDGCLA, UDGCLB, and UDSCLV. 

2.

Call

RUDLEV(NLEV)

3

Explanation of Parameters

NLEV	(I)	Specifies which contour interval to check. (the NLEVth contour interval.)
RUDLEV	(R)	The value of a floating-point function that gives the contour interval.

4.

Notes

(a)

Internally, the values of the (NLEV)th and (NLEV+1)th contour levels are checked by  UDQCLV (see Section 8.2.5), and the difference (the (NLEV+1)th value minus  the (NLEV)th value) is returned. Note that the values of the contour levels inquired by UDQCLV are not necessarily in ascending order.

(b)

Two or more contour levels must be set. Also, NLEV must be larger than 1 and smaller than the total number of contour levels set. When this condition is not satisfied, RUDVAL gives an alert message and 0 is returned.