Abstract:The DLG warehouse data is one of the main basic surveying and mapping achievements, and the DLG warehouse data has been constantly updated. Because many departments require the mapping data with DWG data format, thus, it is very necessary to realize the automatic conversion from DLG warehouse datas to mapping datas. Polygon elements are important parts of DLG datas. Realizing autofilling of regional symbols of polygon is the key part of automatic conversion from DLG warehouse datas to mapping datas. In this paper, an autofilling method of polygon symbols has been put forward. This method takes many complex graphics into account and solves autofilling symbols of the small area polygon. It is proved this method can achieve the automatic conversion of polygon elements from DLG warehouse datas to mapping datas.