In WWDC 2014 session 708 Apple gave a introduction about indoor positioning. The indoor positioning is a area which cannot be covered using GPS as the signals are not expected to be accurate enough inside steal and concrete structure.So the the available signals were WiFi and beacons using BLE.
In order to get the venue mapped we have to setup/overlay the venue layout over the geographical map and manage the conversions between Geographic coordinate systems (Latitude/Longitude), floor plan PDF coordinate systems (x,y), and MapKit coordinates.There is a footprint application code available at apple developer.
But before you jump to get your house mapped and start tracking your cat you have to get your venue indoorpositioning enabled by apple.
You can signup at Apple Map Connect
But there are few prerequisite as apple is known to keep it self class apart.You must qualify in order to get your venue indoor positioning enabled . At the time of writing of the blog they were
1.Venue should be Accessible to common public. (your home goes out. look for estimote sdk)
2.Annual Visitors in excess of 1 million per year.(Your gym goes out here)
3.Availability of complete,accurate, and scaled reference maps.
4.Enabled with WiFi throughout
5.Associated app is authorized by venue owner.
Apple has also launched a survey app Indoor Survey.
As for a small venue beacons remain the best bet with Estimote providing decent indoor maping