土壤专题图中采样点点位标识模型的构建

DEVELOPMENT OF SOIL SAMPLING POINT LABEING MODEL FOR THE MATIC SOIL MAPS

采样点图在直观展示已采集样点分布同时,也为确定补充采样点的位置提供了参考。制图时,通常以采样点编码在地图图面标识各个采样点,但由于受空间地理位置影响,采样点标识常呈无序排列,当地图中采样点密度及地图幅面较大时,读图时难以查找目标采样点。为实现制图后的采样点标识呈有序排列,构建了"土壤专题图中采样点位标识模型(Soil Sampling Point Labeling Model for Thematic Soil Maps:SAMPLA)",该模型主要有读图视区划分模型;土壤采样点位归属读图视区判定模型;土壤采样点顺序标识模型等3个子模型组成。基于Arc GIS 10.0,采用C#语言进行计算机编程,实现了SAMPLA。用1∶50 000国家标准分幅和县级地图的土壤采样点对模型进行验证,验证结果表明,模型可适用于不同类型分幅地图、不同比例尺,有助于实现规范化、批量化制图,提高了读图效率;但是读图视区划分方案对标识结果有一定影响;其他行业专业领域,如环境科学、水科学、地质科学等在制作类似于土壤采样点的点位图层时也可采用此模型。

Sampling site maps not only show intuitively distribution of the sampling sites where soil samples have been collected, but also provide reference for researchers to determine where supplementary soil samples should be taken. Traditionally, in soil mapping, codes were used to label each sampling point in the map for identification. However, as affected by their spatial geographic locations, it is impossible to label the sampling sites in sequence, thus making it very hard to locate a required sampling site in the map, especially when it has too many sampling sites located densely or is too large in format. To realize orderly labeling of sampling points, a ＂ Soil Sampling Point Labeling Model for thematic soil maps （SAMPLA）＂ was developed, consisting of three sub-models, i.e. map reading vision zone division model, soil sampling site attribution map reading vision zone determination model and, sampling point sequential labeling model. With the aid of ArcGIS 10.0 and Human Machine Interaction（HMI） design, SAMPLA was translated into a computer program with the C# programming language, and tested with soil sampling points in the 1：50 000 national standard map sheets and county-level maps. Results show that the model is applicable to maps different in type and scale, helps realize standard- ized mass mapping, and improves map reading efficiency. But labeling was slightly affected by the map reading vision zone division program. However, besides in soil sciences, SAMPLA can also be used in other scientific fields, such as environ- mental science, water science, and geological science, for making sampling point distribution maps.