系列比例尺地形数据库信息量比较——以1∶250000和11∶000000居民地为例

Comparing the amount of information for multi-scale national topographic database

合理度量地理信息信息量可为信息的生产者、质量控制者和用户描述、评价、选用相关产品提供相关技术依据。本文在总结了已有地形数据库信息量量测研究现状后,选择一幅国家11∶000000地形数据和对应范围内的16幅1∶250000地形数据中的居民地要素层,全面分析评价了该要素层的统计信息量,几何信息量和专题(属性)信息量及其在不同比例尺之间的关系。实验表明,对地形数据库中的要素层采用全面评价的方法是可行和必要的,在各比例尺的居民地的信息量之间存在一定的数量关系,同时也部分验证了在地图缩编时为保持信息量最大化所要采取的必要措施的理论依据。

Reasonably measuring the amount of information can provide technique foundations for describing, evaluating, and choosing products by producers, quality controllers of information and users. In this paper, existing measures for map information were analyzed. An experiment was conducted by selecting a sheet of 1：1 000 000 map and 16 sheets of 1：250 000 maps covering the same area from national topographic database and the assessed feature was point residential layer. The authors completely evaluated statistical information, geometric information, and thematic （attribute） information entropy. Results shows that entirely evaluating the amount of information for features is necessary and feasible, and it can reflect the distribution and thematic （attribute） characteristics for features in topographic database. At the same time it is necessary to provide combination of various information capacities for completely evaluating a topographic map.