Abstract: In order to meet the requirement of updating other scale topographic maps with 1:500 topographic map, a method of automatic downsizing and updating at the same scale level and across scale level based on topographic map database is proposed.Through the design of topographic map template and transition template, defining the conversion rules of comprehensive feature elements, developing automatic downsizing software module, customizing the task of automatic downsizing and updating, automatically downloading the topographic map data by using the survey update range line in the database for downsizing and updating, Which realize the goal of successively downsizing and updating large-scale topographic map to obtain various scale topographic maps.The technical method proposed in this paper has been verified in the updating of urban basic geographic information database of Changsha city, which provides technical experience for rapid acquisition of diverse geographic information data by downsizing.

Key words: topographic map database, automatic downsizing, update stock in, surveying update range line, cross scale, task customization