Abstract: A data structure of the voxel data VD according to this example is a map data structure which is a data structure of map data to be referred to by an information processing device 1, and includes position information indicating a position of a structural object and attribution information indicating whether or not the structural object is a floating object on a water surface. If the attribute information indicates that the structural object is a floating object on a water surface, the attribute information is used by the information processing device 1 to identify the position of the structural object by using the position information as relative position information relative to a position of the water surface.

Abstract: In the information processing device, the point cloud data acquisition means acquires point cloud data generated by a measurement device provided on a ship. The water-surface reflection data extraction means extracts data obtained by measuring a position which is a predetermined distance away from a shore and which is within a predetermined distance from a measurement position of the measurement device, as a water-surface reflection data measured by reflection at a water surface. Then, the water-surface height calculation means calculates a water-surface height based on the water-surface reflection data.

Abstract: In the information processing device, the object detection means detects an object based on point cloud data generated by a measurement device provided on a ship. The positional relationship acquisition means to acquires a relative positional relationship between the object and the ship. The display control means displays, on a display device, information related to the positional relationship in a display mode according to the positional relationship.