Smart data compression
Smart Data Compression is a compressed GIS data format; the files have the file extension sdc . All types of feature and attribute data are stored together in sdc files. It was developed by the company ESRI for their ArcGIS package. The SDC format is used by ESRI for the products ArcGIS StreetMap, ArcIMS Route Server, RouteMAP IMS, ArcGIS Business Analyst and ArcMobile SDK.
The compression rate ranges from 8 to 20 times the size of the original data volume. ESRI uses this format, for example, to make free data accessible on its homepage and to ensure that it can be accessed quickly on the Internet.