# Least Cost Path and Distance: Cost Distance Raster Gives the Total Cost Accumulated by Optimal Route (Especially for GATE-Geospatial 2022)

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A cost raster defines the cost or impedance to move through each cell. The cost distance measure is based on the node-link cell representation. The process for finding the least accumulative cost path is an iterative process based on Dijkstra՚s algorithm.

## Deriving the Least Accumulative Cost Path

Easy to calculate cost between two cells

The cumulative cost from cell to cell is the sum of 1.0 and 3.5, the costs of two lateral links. The cumulative cost from cell to cell is the sum of 4.2 and 2.5, the costs of a diagonal link and a lateral link

The cost distance for each link (c) and the least accumulative cost distance from each cell (d) are derived using the source cells (a) and the cost raster (b) .

The least cost path (a) and the allocation raster (b) are derived using the same input data in above figure.

## Improvements for Cost Distance Measure

Measures presented assume an isotropic surface. Cost surface not uniform. Terrain changes in slope, elevation, aspect. New variables suggested providing more realistic analysis.

### New Variables

Surface distance calculated from elevation raster. It can measures actual ground distance. They have vertical and horizontal factors.