Overlays can be thought of as transparent sheets on which any graphical data is placed. The term Overlay is used to describe a view of a dataset. A dataset can be:

  • a read-only graphical file (e.g. an NTF, DXF, or BMP file)
  • a user dataset (BDS file)
  • a database (IDB file)
  • stored within the SIS Workspace Definition (SWD) (internal dataset or index dataset)
  • data retrieved from a spatial database, e.g. Oracle, PostGIS, Microsoft SQL Server 2008.
  • an internal binary geometry dataset

TIP: For a full list of datasets that can be included as overlays, see also Dataset Formats.