基于规则库和网格算法的土地利用现状图自动数字注记

Automated Numeric Placement for Land Utilization Map Based on Rule Database and Grid Algorithm

图形自动注记可极大地提高制图的工作效率。针对土地利用现状图数字注记的特点,本文从地图认知角度出发,建立注记自动配置的规则库,提出面状要素自动注记的一种新的算法——网格法。该算法最大的优点是容易实现、效率高,可方便地解决注记压盖冲突等问题。通过开发一个程序实例,对图斑要素进行了自动数字注记,实验表明95%以上的图形注记效果都较为理想。

Automated placement helps greatly improve the efficiency of cartography. Annotation of map can be divided into name, numeric, illustrative annotation. Almost all researches care about name placement. But numeric annotation has some difference from name, which for example is of fixed length and must be fetched from field value of background feature and so on. According to the character of numeric annotation of land utilization map, rule database is proposed, with which the program can be configured dynamically. And a new Grid Algorithm for region automated placement is put forward which can solve the conflict of overlap between labels, and be applied to program more easily and efficiently. Furthermore, down-lead label of little parcel, update of numeric annotation together with its related parcel, are also discussed. Based on this nile database and grid algorithm, an application of automated numeric placement for land utilization map is developed, which is proved to be effective for above 95 percent of parcels in utilization map.