1. A method for enhancing local contrast of an image in a GIS (Geographic Information System) application, the method comprising computing column-wise sum for all pixels in the 0 th row up to extent of a Wallis window for the 0 th row; storing the computed column-wise in memodata 1 ; computing column-wise sum of squares for all pixels in the 0 th row up to extent of the Wallis window for the 0 th row; storing the computed column-wise in memodata 2 ; computing new pixel colours of the 0 th row using horizontal memoization; computing column-wise sum for all pixels in next row incrementally, on incrementing the row; computing column-wise sum of squares for all pixels in next row incrementally, on incrementing the row; and computing new pixel colours of each row using horizontal memoization, till all rows are completed.