visual variable造句

( 4 ) finally , it expatiates the design of map symbols and representation methods for thematic maps , and then explains the importance of the dynamic symbols and representation method in electronic atlas and analyzes visual variables " influence on symbol design , and at last specializes the choice of representation method with real examples and realizes the thematic mapping system based on mapx control
( 4 )阐述了《军官地图集》电子版中专题地图的符号设计和表示方法的设计。说明了动态符号和表示方法在电子地图集中的重要作用，分析了各个视觉变量对符号设计的影响，叙述了《军官地图集》电子版中表示方法的选择并以实例表述，实现了基于控件的专题地图制图系统。
It's difficult to find visual variable in a sentence. 用visual variable造句挺难的