If you want to add an ESRI shape (.shp) file to the map view, then you must select a Shape overlay.
Shape File and Item - In the file browser dialogue you can select from the available items in the .shp file.
Parameters for Points - This section allows you to customize the way point .shp themes are displayed.
Parameters for Lines and Polygons - This section allows you to customize the way line and polygon themes are displayed.
Units - The ESRI .shp format does not include information on whether the length units are SI or Imperial. So, this combobox allows you to select the length units from a range of SI and Imperial length units.
