用于等高线图到数字高度图（Digital Elevation Map)转换的转换算法是很多应用都需要的算法，为了提高这一转换的精度与效率，一个相应的算法－区域内插法被特别提出来，该算法利用了等高线图固有的特性，即“图象被等高线分割成多个区域，每个区域内的边界只有两个等高线值”的特性，该算法可以在计算机上快速实现，经过与现有的象限搜索法的实验比较，由于它更好地利用了等高线图结构上的特点，致使其在提高速度的同时，精度上较象限搜索法也有很大的提高，因而具有很强的实用价值。

Algorithms to reconstruct digital elevation map(DEM) from elevation contour is widely used in many applications. In the process of designing a 3D terrain visualization program, where only elevation contour map is available, a new method, region intra interpolation algorithm, was proposed. It utilizes the structural features of elevation contour images, that is, image is partitioned into many regions by elevation contours and each region is only bound to at most 2 elevation values. Therefore each point inside this region can be calculated as a linear interpolation from the two boundary values. The problem then turns into finding the two shortest distances to its bounding elevation contours. Fast realization is also given out, and this speed up also achieved by special design utilizing elevation contour structures to save time on searching for the closest points. Compare with current algorithm like Quadrant Search algorithm, which is design based on a model of random distributing of known value, it shows good performance on both speed and accuracy.