Distance Matrix is the matrix of distances between stations in a station set. The distances can be real geographic distances between station coordinates or crow fly distances (i.e. direct distances over earth).
Road Distance Matrix
Road Distance Matrix is the distance matrix in which the values are retrieved from underlying GIS system automatically as real world distances according to minimum road network map. Therefore, the values in Road Distance Matrix reflects the real distances from one station to another station by traveling on the road network.
Crow Fly Distance (CFD) Matrix
Crow Fly Distance (CFD) Matrix is the distance matrix in which the values are retrieved from underlying GIS system automatically as minimum distances over earth surface without traveling on road network. Therefore, the values in CFD are not the actual world travel distances by road network. It can be considered as a minimum flight distance matrix.