Abstract: The relation between the concept of remote sensing/GIS uncertainty and the uncertainty of information theory is discussed,to enable quantitative evaluation of the measurement of information and uncertainty of remote sensing and GIS data.The formulation for calculating information content of GIS graphics data is inferred based on the definition of uncertain degree in information theory.With this formulation,the information of geometric position and attribute can be measured in the unit of bit.Furthermore,the information of any geographic target in GIS is measurable by considering the doubtfulness of geometric position and attribute.Besides GIS vector data,the information of remote sensing raster imagery is also discussed.