Abstract: Quantitative measurement for map information is one of the basic research issues in the field of theoretic cartography. It is recognized as an indicator for evaluating the efficiency of both map design and map generalization as well as the practical value of a map. Taking a typical map, contour map as example, this paper develops a methodology for measuring the information content of the contours in a map in a hierarchy. Existing methods of measuring the information content of a map are first summarized, which are almost based on Shannon information theory. Then, the sources of contour map information and its nature is discovered. It is found that the information of a contour map is able to be described into three levels, namely, element level, neighborhood level and global level. At the element level, it means the information of a contour line; at the neighborhood level, it refers to the information of basic geomorphic unit; and at the global level, the distribution information of whole geomorphology in a contour map is indicated. Moreover, all levels of information are measured from the nature of information source, i.e. variability and diversity. Finally, some practical examples are provided to illustrate the proposed methods in this paper.