Elevation automatic sparsing is an important job while dealing with elevation points In AutoCAD topographic map downsizing,and which method we adopt to proceed it will be discussed here.

For satisfing all kinds of needs,the different map scale was needed,and the map generalization is one of the apporachs that was widly adopted in the application areas.

By discussing the problems needed to solve by aerial survey large-scaled topographical maps editor program,and the necessity of developing software was provided,the making idea,using method and practice use efficiency of program were introduced mainly,and it pointed out that the work efficiency was improved obviously by using this program.

On making a thorough investigation and study,the mathematics model of new topographic map code and map range are set up.