Introductory Example

The TRANS Procedure

Introductory Example

Consider the SAS data set in Figure 6.1. The SAS code used to create the data set can be found in Example 6.1.

Uncapacitated Transportation Network

Obs	Atlanta	Chicago	Denver	Houston	Los_Ange	Miami	New_York	San_Fran	Seattle	Washingt	supply	city
1	50	75	89	8	27	39	64	100	50	8	.
2	20	58	121	70	193	60	74	213	218	54	10	Atlanta
3	58	20	92	94	174	118	71	185	173	57	150	Chicago
4	121	92	20	87	83	172	163	94	102	149	90	Denver
5	70	94	87	20	137	96	142	154	189	122	27	Houston
6	193	174	83	137	20	223	245	34	95	230	80	Los_Ange
7	60	118	172	96	233	20	109	259	273	92	26	Miami
8	74	71	163	142	245	109	20	257	240	20	80	New_York
9	213	185	94	164	34	259	257	20	67	244	25	San_Fran
10	218	173	102	189	95	273	240	67	20	232	7	Seattle
11	54	59	149	122	230	92	20	244	232	20	15	Washingt

Figure 6.1: Introductory Example Input Data Set

The first observation provides the number of units demanded at each destination node. The supply variable provides the number of units supplied at each source node. If you exclude the first observation and the supply variable, the remaining values are the cost of shipping one unit between nodes. For example, the per unit transportation cost between Miami and Houston is 96. The transportation problem is solved when the minimum total cost flow between supply points and destination points that satisfies the demand is found. PROC TRANS solves this problem and produces a SAS data set containing the number of units to ship between each supply point and demand point. It does not produce any output but does report the minimum cost on the log. See Example 6.1 for the results.

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