地图边界提取的递归算法

A Recursive Algorithm for Extracting Boundary Data of Digital Map

通过一个递归算法完成对数字图像中地图边界的顺序跟踪提取,再转化成相应的经纬度坐标后,就可以应用于气象绘图软件GrADs、Vis5D、Surfer及MICAPS系统中进行底图的制作。利用这个方法,对于无法获得地图边界点经纬度坐标(如城市的行政区界线)时,能够直接从数字图像中完成所需信息的提取,以满足密集气象监测网和高空间分辨率的天气要素的图形化要求。应用于气象绘图和业务系统中,可解决缺少地图边界点经纬度数据时的地图绘制问题,并给出了应用示例。

By means of a recursive algorithm, the tracking and extracting of the boundary data from the digital image of a map is realized, and then after converted into the corresponding longitude and latitude coordinates, these data can be applied to the meteorological plotting software GRADS, VisSD, Surfer and MICAPS to plot the background map. With the method, the extracting of the needed messages from the digital image can be realized directly for the difficult-to-acquire longitude and latitude coordinates of boundary points of the map （such as the district boundary lines of a city）, so to meet the needs of the intensive meteorological monitoring network and the visualization of high spatial resolution meteorological elements. Solved the problem about the lack of the longitude and latitude coordinates of boundary points of a map, the method can be used in meteorological plotting and to various operation systems. An application example is given.