Smart Data Compression

Smart Data Compression (SDC) is a compressed GIS dataset format developed by Esri. It is used for vector format data only and stores all types of feature data and attribute information together as a core data structure. The SDC format is used in Esri products such as ArcGIS StreetMap, ArcIMS Route Server, RouteMAP IMS, ArcGIS Business Analyst, and the ArcMobile SDK.

Compression ratios range from 8x to 20x depending on the data source and structure. SDC data is optimized for rapid map display, accurate routing, and high-performance geocoding.

Smart Data Compression is a proprietary format. The FAQ for Esri's RouteServer IMS notes that additional datasets for that application must be prepared by an Esri subsidiary at additional cost. The SDC technology was developed (like other Esri technology) by Data East, LLC, in Russia. Tele Atlas and NAVTEQ provide North American commercial street datasets in SDC format. This data was prepared using the Data Development Kit Pro (DDK Pro), which Esri licenses to select vendors.

SDC and ArcMap Products

SDC data can be created in a limited fashion in Esri ArcMap for the use as basemaps in mobile units. The tool to accomplish this is found under the Mobile Tools, and is called Create Mobile Basemap. This tool allows users to create basemaps for their mobile devices that can then be edited in the field. There are some limitations to an SDC file created this way. The main limitation is that the file has a 4 GB cap. It is not recommended to approach this cap as then further edits cannot be done in the field, and other problems may arise.

Suggestions for Creation of SDC Data

When creating SDC data there are several things users should be aware of to avoid hitting the size cap mentioned above. Users should try to keep their maps as simple as possible, including only the layers that are necessary. In ArcMap users should also avoid using definition questions, selection layers, joined tables and other advanced ArcMap behaviors. The length and size of the attribute tables should be monitored as well. If files have a large amount of attributes in their tables this can rapidly increase the size of the file and lead to the cap being hit.