| 摘要 |
PROBLEM TO BE SOLVED: To automatically and efficiently extract an upstream area in the case of defining a certain position as an origin concerning a sewerage mapping system for managing data in mesh. SOLUTION: Concerning the data of departure mesh 71, tracing is performed from an origin 73 to an upstream side boundary node (inflow node). When there are plural nodes on the upstream side, they are temporarily preserved in an internal stacker and the respective nodes are successively traced. Next, an adjacent mesh with the inflow node of departure mesh 71 as an outflow node is found and while using a prepared inflow/outflow table, the inflow node on the upstream side of outflow node is found. Similarly, upstream side meshes are successively traced until the upstream side inflow nodes are eliminated. When there are plural inflow nodes on the upstream side, they are temporarily preserved in a boundary stacker and the respective nodes are successively traced. |
