Blank screen.
The measurement uses Pythagoras’ theorem to calculate the height of the measured object and therefore needs to know the height of the camera above ground in order to accurately measure the distance from the base of the building.
It should be noted that the equation relies upon the horizontal distance to the base being the same at the top and bottom of the target, the top must be perpendicular to the bottom. For instance, no accurate measurement could be made of Nelson’s column, the target at the top is further away horizontally than the plinth at the base. This would not prevent you doing a number of measurements but it does make it more difficult. Neither would have been possible as the App failed to display and all I got was a blank screen.