Research for comparison and definition on the granularities of urban geospatial data

In this paper,the author presents six critical spatial levels on urban geospatial data with,the diameter of Spatial data polygon's average equal-area circle as Characteristic scales of granularity,and builds a mathematical model of space granularities and spatial level,then grades the granularities of each spatial level.Taking the research precision of urban problem as selective condition,the author explores a method of choosing proper spatial level according to the grade of granularities.