Method for performing color gradation optimization on DEM shading map to highlight ancient dam

The invention discloses a method for carrying out color gradation optimization on a DEM (Digital Elevation Model) shaded map to highlight an ancient dam, which comprises the following steps of: generating an initial DEM shaded map, superposing a digital contour line topographic map, determining an altitude range of a target ancient dam, carrying out color gradation optimization processing, and displaying the ancient dam. The color gradation optimization comprises the steps of properly expanding the altitude range of a target ancient dam and taking the altitude range as an optimization range, customizing the color gradation, generating an optimized DEM shaded relief map and completing details, and the custom color gradation comprises the steps of enriching basic colors, setting more grades in the optimization range, and setting less grades in altitude ranges lower than and higher than the optimization range. The method is used for solving the problem that the target ancient dam cannot be highlighted generally