Patent ID: 11954410
Assignee: DREXEL UNIVERSITY
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 9:
10. A method using a Haag Shokoufandeh Marching (HSM) algorithm that returns a watershed boundary, the method comprising:
accepting as input a grid cell v* and a D8 graph G, wherein the D8 graph G vertices are labeled with discovery time and finish-time, wherein within a structure of the D8 graph G, every grid cell is connected with eight neighboring grid cells associated with a respected grid cell, wherein the HSM algorithm marches around a watershed identifying valid edges and returning to an original starting location, wherein marching the HSM algorithm includes identifying a valid march direction based on a current march location of the HSM algorithm, wherein an abstraction of a flow direction grid G is created based on a pour point of the watershed, wherein the abstraction denotes at least one lattice point of each grid cell of the watershed, wherein a modified nested set (MNS) is applied to the abstraction of the flow direction grid G, wherein a Boundary Point (BNP) function returns a Boolean value for two grid cells in front of the current march location, and wherein based on previous march step and outcome of combinations of the BNP function calls, the march is extended.