GS utilizes a central GIS theme based on ESRI (ArcView) software objects. These create powerful GIS capabilities within GS that link its well database to "real world" GIS formats where it can be integrated with virtually any other spatial information such as maps, seismic lines, cross sections, raster logs, etc. Many vector and raster formats are supported; ArcView "Shape" files, CAD formats (DXF, DWG, DGN), GeoTIFF, JPEG, ERDAS, and MrSID image compression. There are options for layering all this spatial data to create advanced maps, along with spatial and logical queries on map layers. The opening GS menu is simple and intuitive, and is very easy to learn.