船舶导航场景海事航标（灯塔）数据
收藏资源简介：
船舶导航应用中，用户可根据其当前经纬度位置来查找所处海区的所有灯塔数据，可以帮助用户进行航线规划，确定船舶位置和航向，使船舶沿航道和预定航线安全航行，保障船舶航行安全。灯塔数据中的坐标和半径为geom数据，主要对geom数据进行加工处理，数据存储为WKT格式，一部分描述空间几何对象的类型和坐标系信息（例：LINESTRING (x1 y1, x2 y2, ..., xn yn)），另一部分则是空间几何对象的坐标点的序列，系统通过坐标类型的枚举匹配识别出当前WKT的对象类型，然后根据对象类型对其包含的空间信息进行二次处理，根据点、线、面、多线、多面等情况进行处理后生成经纬度列表数据list，根据射线法判断两个面是否相交，射线法主要思想是从一个点（通常是多边形的重心）发出一条射线，然后计算这条射线穿过多边形的边数。如果穿过的边数为奇数，则这个点在多边形内部；反之则在多边形外部，最后将list划分至对应的海区，船舶在导航过程中，根据其当前经纬度位置来判断所处海区，并将海区中所有的海事航标在海图上显示。
In ship navigation applications, users can retrieve all lighthouse data in the current sea area based on their current latitude and longitude coordinates. This functionality assists users in route planning, determining the ship's position and heading, enabling safe navigation along designated waterways and pre-planned routes, and safeguarding overall ship navigation safety. The coordinates and radius within the lighthouse dataset belong to geom data, with the primary processing target being the geom data, which is stored in Well-Known Text (WKT) format. A portion of the WKT string describes the type and coordinate system information of spatial geometric objects (e.g., LINESTRING (x1 y1, x2 y2, ..., xn yn)), while the other part consists of the sequence of coordinate points of the spatial geometric object. The system identifies the type of the current WKT object through enumeration matching of coordinate types, then performs secondary processing on the contained spatial information. After processing scenarios including points, lines, polygons, multi-lines and multi-polygons, a latitude and longitude list (list) is generated. Next, the ray casting algorithm is used to determine whether two polygons intersect. The core principle of this algorithm is to emit a ray from a reference point (usually the centroid of a polygon), then calculate the number of polygon edges that the ray crosses. If the number of crossed edges is odd, the reference point lies inside the polygon; conversely, it lies outside the polygon. Finally, the generated latitude and longitude list is divided into corresponding sea areas. During the ship's navigation process, the ship's current sea area is determined based on its real-time latitude and longitude coordinates, and all maritime navigation aids within that sea area are displayed on the nautical chart.
