It has traditionally contained external data such as ArcInfo Shapefiles and MapInfo MIF/MID files. This data can be converted to Map Module Features for various purposes such as inclusion in a conceptual model to create a mesh/grid, or for inclusion in a simulation. SMS includes two separate ways of working with or managing external GIS vector data. The first uses internal SMS functionality to select, edit and convert GIS data to other data types in SMS. The second includes a link to ArcObjects to allow direct management of the GIS data. This option is described below. Starting with SMS version 12.0, the GIS module was modified to be consistent with the Groundwater Modeling System (GMS) and the Watershed Modeling System (WMS). With this merging of functionality, the GIS module is used to manage all external geographical data including: When opening a file recognized as a GIS data type, SMS will create an entry in the project explorer for that object. The object may contain any combination of the following: In addition to data type, the data source for a GIS object may be static (a single file) or dynamic (a link to a web site). The icon, displayed to the left of the entry of the tree indicates what type(s) of data reside in that object and whether the object is static or dynamic. By right-clicking on a GIS object in the project explorer, the popup menu shows the applications for the specific data type contained in the selected object. To interpolate from a DEM or image with elevation data, right-click on the object and select Interpolate | <,target>, (where <,target>, defines the object the values are being interpolated to such as a scatter set, grid or mesh). The principal application of this is to assign geometric elevations or depths to the geometry. Another application is to assign spatial attributes based on land use attributes, land cover attributes, or another set of values on the DEM. This is currently available in the ADCIRC menu under the Nodal Attributes command. Selecting the land use coverage to populate a specific nodal attribute will average the values over the area of interest. These commands create new geometric entities in the SMS project such as a scatter set or feature objects. To convet from a DEM (image with elevation data), right-click on the object and select Convert | <,target>, (where <,target>, defines the object being created such as a scatter set or grid. These commands allow manipulating the DEM objects themselves and are accessed by right-clicking on the GIS object. This command uses the selected arcs or nodes in the active coverage to edit the elevation of cells in the DEM. To use the command: Shapefiles can be visualized in SMS as well as be converted to feature objects or scatter data. This can be done by using either the Shapes → Feature Objects or Polygons → TIN command in the Mapping menu. It is important to check for bad polygons when converting shapefile data. These may be polygons with zero area or with duplicate nodes. This problem can be fixed by using the Clean command in the Feature Objects menu. If using the Clean option does not fix the problem initially, try increasing the tolerance until all problematic feature objects are removed. SMS includes the option to use ArcObjects to incorporate much of the ArcGIS/ArcMap/ArcView® functionality directly. Any ArcGIS® supported file (coverages, shapefiles, geodatabases, images, CAD, grids, etc.) can be opened, then used with the ArcGIS® Display Symbology properties to render the GIS data, and then display it in SMS. Most of the same functionality that exists with licenses of ArcGIS® is also available without a license and a license is NOT required for most applications. Source.