Shapefiles are a type of spatial data that consists of dimension less points, lines, or polygons. Their significance depends upon the context in which they are used or displayed. Vector themes can be attached to a FlamMap project as Auxiliary Themes to depict roads or streams that overlay the visible grid theme providing reference and familiarity with the landscape. Shapes files can also be created from vector outputs generated by FlamMap runs or Farsite Simulations.
Shapefiles actually consist of a minimum of three separate files;
a spatial information file (.SHP),
an index file (.SHX),
a dBASE file with attribute information (.DBF).
Typically when opening and saving shapefiles only the .SHP file is listed, but FlamMap manages the required .SHX and .DBF files behind the scenes. There are also many other optional shapefile extensions such as .FBN, .FBX, .SBX, .PRJ, etc that you may see associated with shapefiles created outside of FlamMap. It is important to remember all the file extensions when moving shapefiles or when you get into the mood to clean up your hard drive.