By dropping “points” on a map within the Survey App, you indicate your position within the venue as you walk through. As you do so, the indoor Survey App measures the radio frequency (RF) signal data and combines it with an iPhone’s sensor data. The end result is indoor positioning without the need to install special hardware…
This information is coming from a tweet by Steve Stroughton-Smith who noticed the app on his iOS device while in the App Store.
the app is intended for use by businesses using the Apple Maps Connect service, which allows them to add and edit entries appearing in Apple Maps. Apple Maps entries cover everything from gas stations to stores, restaurants and hotels.
The idea would be that, once you walk into a store, for example, Apple Maps would be able to direct you to the section or department you need.
The app may well have been developed using technology created WiFiSLAM, a company Apple acquired back in 2013. The tech uses WiFI signals to track the location of smartphones within buildings, and is a good match for the functionality described by Indoor Survey.