Route point setting device and route point setting program

1. A route point setting device that sets route points on a flight route from a predetermined first point to a predetermined second point, the route point setting device comprising:

a grid divider that divides map information into a plurality of cells in grid form on a horizontal plane, the map information including at least the first point and the second point;

a cell route setter that sets a cell route including consecutive cells from the first point to the second point on the map information subjected to the grid division by the grid divider;

a calculator that calculates a bending angle of the cell route at each cell on the cell route; and

a route point setter that performs comparing the bending angle at any cell calculated by the calculator, with the bending angles at two cells adjacent to the any cell and respectively ahead of and behind the any cell on the cell route, and setting the any cell as a cell route point in a case where the bending angle θ n at the any cell satisfies an expression

θ n−1 ≧θ n <θ n+1

where, in a direction from either one of the first and second points to the other point, θ n−1 represents the bending angle at the cell adjacent on a start point side to the any cell on the cell route, and θ n+1 represents the bending angle at the cell adjacent on an end point side to the any cell on the cell route, the any cell including all cells on the cell route.

2. The route point setting device according to claim 1 ,

wherein the route point setter performs the comparing of the bending angle at each cell, sequentially following the cell route, having started at either one of the first point and the second point, and

wherein, in a case where the bending angle of the cell where the comparing is being performed has consecutively been smaller than the bending angle at the immediately previous cell for a predetermined number of times or more, the cell where the comparing is being performed is set as the route point.

3. The route point setting device according to claim 1 ,

wherein the calculator calculates, for any cell on the cell route, two vectors that each are a vector from the any cell to a cell backwards by a predetermined number of cells on the cell route and a vector from the any cell to a cell forwards by the predetermined number of cells on the cell route, and calculates an angle formed by the two vectors as the bending angle.

4. The route point setting device according to claim 2 ,

wherein the calculator calculates, for any cell on the cell route, two vectors that each are a vector from the any cell to a cell backwards by a predetermined number of cells on the cell route and a vector from the any cell to a cell forwards by the predetermined number of cells on the cell route, and calculates an angle formed by the two vectors as the bending angle.

5. A route point setting program stored on a non-transitory computer readable medium that sets route points on a flight route from a predetermined first point to a second point, the program causing a computer to perform:

a grid dividing function of dividing map information into a plurality of cells in grid form on a horizontal plane, the map information including at least the first point and the second point;

a cell route setting function of setting a cell route including consecutive cells

from the first point to the second point on the map information subjected to the grid division by the grid dividing function;

a calculating function of calculating a bending angle of the cell route at each cell on the cell route; and

a route point setting function of performing comparing the bending angle at any cell calculated by the calculating function, with the bending angles at two cells adjacent to and respectively ahead of and behind the any cell on the cell route, and setting the any cell as a route point in a case where the bending angle at the any cell satisfies an expression

θ n− 1≧θ n<θn+ 1

where, in a direction from either one of the first and second points to the other point, θ n−1 represents the bending angle at the cell adjacent on an end point side to the any cell on the cell route, and θ n+1 represents the bending angle at the cell adjacent on a start point side to the any cell on the cell route, the any cell including all cells on the cell route.