The NETDRAW Procedure

Example 9.6 Nonstandard Precedence Relationships

This example illustrates the use of the LAG= option to indicate nonstandard precedence relationships between activities. Consider the widget manufacturing project described in the earlier examples. Some of the precedence constraints between the activities may be nonstandard or have a nonzero lag value. For example, the activity 'Init. Prod.' may not be able to start until 2 days after the completion of the activity 'Facility.' The Network data set is displayed in Output 9.6.1. The variable lagdur indicates the type of relationship between the activities specified in the variables task and succ.

The following statements invoke PROC NETDRAW with the LAG= option. The resulting network diagram is shown in Output 9.6.2.

pattern1 v=e c=green;

title h=3 'Widget Manufacture';
title2 h=2 'Nonstandard Precedence Constraints';

proc netdraw graphics data=widglag;
   actnet / act=task
            htext=3 boxht=3 arrowhead=2
            xbetween=7 ybetween=9

Output 9.6.1: Network with Nonstandard Precedence Constraints

Widget Manufacture
Network Data Set

Obs task days succ lagdur
1 Approve Plan 5 Drawings  
2 Approve Plan 5 Study Market  
3 Approve Plan 5 Write Specs  
4 Drawings 10 Prototype  
5 Study Market 5 Mkt. Strat.  
6 Write Specs 5 Prototype  
7 Prototype 15 Materials ss_9
8 Prototype 15 Facility ss_9
9 Mkt. Strat. 10 Test Market  
10 Mkt. Strat. 10 Marketing  
11 Materials 10 Init. Prod.  
12 Facility 10 Init. Prod. fs_2
13 Init. Prod. 10 Test Market  
14 Init. Prod. 10 Marketing  
15 Init. Prod. 10 Evaluate  
16 Evaluate 10 Changes ss_6
17 Test Market 15 Changes ff_3
18 Changes 5 Production  
19 Production 0    
20 Marketing 0    

Output 9.6.2: Network Diagram with Nonstandard Precedence Constraints

Network Diagram with Nonstandard Precedence Constraints