Piping diagram creation method and piping diagram creation device

A piping diagram creation method for creating a piping diagram of a pipeline connecting a plurality of intersections specified on a map between a start point and an end point and passing through a control point selectively specified between the respective intersections, the method comprising:

• a first step of selecting fittings to be disposed at the respective intersections;
• a second step of determining a number of straight pipes required, presence or absence of cut pipes, and a length of the cut pipes, based on a distance between the respective intersections and a length of the straight pipes;
• a third step of generating virtual pipelines on which the straight pipes and the cut pipes determined at the second step are allocated between the respective intersections, each of the virtual pipelines being identified by characteristic evaluation data expressed as a sequence of numbers with an assembling angle θi, i is a number of assembling portions, of assembling portions of the respective straight pipes and cut pipes constituting the virtual pipeline and an adjustment margin Lj, j is a number of cut pipes, of the cut pipe length as variables that are settable within a predetermined allowable range;
• a fourth step of calculating an evaluation value of each of the virtual pipelines generated at the third step based on
• a first characteristic value identified by a difference value between a total number of intersections and control points and a number of intersections and control points each having an error at or below a predetermined threshold, the number of intersections and control points being a continuous count from a start point, the error being defined as an amount of misalignment between the virtual pipeline and each intersection and between the virtual pipeline and each control point,
• a second characteristic value identified by the error at one of the intersections or the control point that first exceeds the threshold,
• a third characteristic value identified by an average value of the errors at the intersections and the control point having the errors at or below the threshold, and
• a fourth characteristic value identified by a proportion of a number of assembling portions with the assembling angle θi of other than 0 degrees, within a range from the start point to the intersections and the control point having the errors at or below the threshold;
• a fifth step of selecting one virtual pipeline from the virtual pipelines based on the evaluation value;
• and
• a sixth step of generating a pipeline assembling diagram based on characteristic evaluation data of the virtual pipeline selected at the fifth step.