The North-West Corner Method (NWCM) is a simple and straightforward approach used to find an initial feasible solution for a transportation problem in operations research. It is called the North-West Corner Method because it starts allocating supply from the top-left (north-west) corner of the transportation table.
Steps to Apply the North-West Corner Method:
-
Start at the North-West Corner (Top-Left Cell) of the cost matrix.
-
Allocate as much as possible to this cell, either:
-
The minimum of supply and demand for that row/column.
-
If supply is exhausted, move down to the next row.
-
If demand is met, move right to the next column.
-
-
Repeat the process for the next available cell until all supply and demand constraints are met.
Example:
Given Transportation Table
D1 | D2 | D3 | Supply | |
---|---|---|---|---|
S1 | 4 | 3 | 2 | 30 |
S2 | 2 | 5 | 3 | 40 |
S3 | 3 | 4 | 6 | 50 |
Demand | 20 | 50 | 50 | 120 |
Step-by-Step Solution:
-
Start at S1-D1 (North-West Corner):
-
Allocate 20 (as demand for D1 is 20).
-
Reduce S1 supply to 10, D1 demand becomes 0.
-
Move right to D2.
-
-
Move to S1-D2:
-
Allocate 10 (remaining S1 supply).
-
Reduce S1 supply to 0, D2 demand becomes 40.
-
Move down to S2.
-
-
Move to S2-D2:
-
Allocate 40 (as supply for S2 is 40).
-
Reduce S2 supply to 0, D2 demand becomes 0.
-
Move right to D3.
-
-
Move to S3-D3:
-
Allocate 50 (remaining supply for S3).
-
Demand for D3 becomes 0, and supply for S3 becomes 0.
-
Final Allocations Table:
D1 | D2 | D3 | Supply | |
---|---|---|---|---|
S1 | 20 | 10 | 0 | 30 |
S2 | 0 | 40 | 0 | 40 |
S3 | 0 | 0 | 50 | 50 |
Demand | 20 | 50 | 50 | 120 |
Advantages of North-West Corner Method:
✔️ Simple and easy to use
✔️ Requires no complex calculations
✔️ Provides a basic feasible solution quickly
Disadvantages of North-West Corner Method:
❌ Ignores transportation costs (May not be the most cost-efficient solution)
❌ May require further optimization using the MODI method or Stepping Stone Method