海洋基础地理数据基准纬线设定方案研究

The Research of the Standard Parallel Solution About Chart Based Data

在建设海洋基础地理数据库时,数据编制常用墨卡托投影,其投影参数对数据质量有较大影响。为使要素的密度均匀,数据的误差可控,同时适应海图产品生产实际,以纬度小于75°为研究区域,分析墨卡托投影的长度变形及不同基准纬线对制图综合指标对应实地距离的影响,统计分析目前出版海图产品基准纬线设定现状,以此为依据分比例尺级别拟定基准纬线方案,为基于数据库的海图数据编制与产品生产提供参考依据。

Mercator is one of the most common projection in marine charting, in which there is no length deformation on the standard parallel.However,the length deformation is very large in the fields away from the standard parallel. When compiling chart based data, the length of the field corresponding to the cartographic generalization parameters affected by Mercator projection is very significant. And these will affect the density and accuracy of chart datain different latitude locations.In order to make the features in uniform density and control data error,this article analyzes the influence on difference between chart showing and real distance caused by the different standard parallel and the length deformation of different fields. According to this to set cartographic generalization parameters. And based on the principle of control the length deformation, the article makes the standard parallel solution about chart based data when building marine geographical database.