林业专题图位图数据的处理方法

THE MANIPULATING METHOD OF FORESTRY THEMATIC MAP BIT DATA

为了进一步完善林业专题图系统,实现常用专题图的快速显示,文章研究了位图数据在计算机的显示缓冲区中的组织结构。通过对显示缓冲区寄存器的正确控制,完成对位图数据的读写操作,读操作存贮该位图数据并形成磁盘数据文件;写操作将所形成的磁盘数据文件直接写入显示缓冲区,恢复屏幕图形。程序用 Microsoft C 5.0和 Microsoft 宏汇编5.0语言编写。运行结果表明,用专题图系统程序输出一幅复杂的专题图需20～30min,而用文章所述的方法恢复一幅相应的专题图不超过5s。

In order to develop the forestry thematic mapping system and realize faster displaying of common thematic maps,the organization structure of bit data was studied in computer video random access memory.This bit data can be directly read and written by contolling registers correctly,the data form into disk file by reading manipulation and the file's data can be written into video random access memory to recover video graph when used.The program has been written using Microsoft C5.0 and MASM5.0 language.The running result proves that thematic mapping system's program will spend 20～30 minutes to output a complex thematic map,but it only spend 5 seconds to recover the corresponding graph by using the method put forward in this paper.