ArcGIS Spatial Analyst provides several distance mapping tools for measuring straight-line (Euclidean) distance and distance measured in terms of other factors such as slope, current road infrastructure, and land use.
Calculating the accumulated cost of travelling, or mapping distance, can provide the user with additional data with which to make decisions. For example, the accumulated least cost of travel to a number of processing mills can be calculated while taking into consideration obstacles to travel. Road and waterway costs can then be assigned to restrict travel.
Euclidean distance and cost distance are two main ways to perform distance analysis in ArcGIS Spatial Analyst. The Euclidean distance functions measure straight-line distance from each cell to the closest source. Not only can you determine allocation, but you can also calculate the distance and direction to the closest source.
The cost-weighted distance function modifies Euclidean distance by equating distance with the cost to travel through any given cell. For example, it may be shorter to climb over the mountain to the destination but faster to walk around it. The cost allocation function identifies the least costly source cell based on accumulated travel cost. The cost direction function provides a road map identifying the route to take from any cell to the nearest source.
Using the cost distance functions, you can create distance and direction rasters and compute the least-cost or shortest path from a chosen destination to your source point. The path distance functions add additional factors beyond the cost surface to account for actual travel distance over the terrain.