摘要
地图符号化将抽象的空间数据转换为可见的地图,其结果以栅格结构存储,进行地图输出时受限于栅格数据量。压缩符号化后的栅格数据来降低计算机资源开销是提高地图输出效率的一种有效途径,据此本文提出利用游程编码表达地图符号的方法,建立面向符号的游程编码数据结构,利用直接的游程运算取代栅格运算来完成地图的各种操作,并在此基础上完成地图输出。该方法减少了数据冗余,直接的游程运算提高了运算粒度,可以满足高分辨率地图输出对处理效率和内存开销的要求。
Map symbols make abstract spatial data visible, in which process the result is preserved in map document in the form of grid data. Obviously, map exporting is restricted by the amount of raster data. Thus, it is an effective approach to compress the symbolization data for the sake of reducing memory consumption. Accordingly, a run length coding approach was proposed to express map symbol in the paper. First, symbol oriented data RLE structure was established to represent previous map symbols. Then, grid operation with directly run length calculation was substituted to achieve various operations. The advantages of the approach in speed and memory consumption would make it highly suitable for dealing with highly precise map output.
出处
《测绘科学》
CSCD
北大核心
2012年第3期110-112,共3页
Science of Surveying and Mapping
基金
江苏高校优势学科建设工程资助项目
关键词
计算机制图
地图输出
游程运算
游程编码
computer cartography
map output
run length operation
run length encoding
