Must be an iphone app. There's no such app for android phones.
Just my humble opinion, but you don't need a fancy app that you need to input data for length and width. A level is a level, whether it's liquid filled or electronic. There are several level apps available for android phones, I would imagine there's quite a few for iphone as well. That's all you need. They use the motion sensors in smart phones to emulate a liquid filled bubble level. They're actually pretty good as long as you calibrate them on something that's known to be level. I calibrate my smart phone level app on our pool table. The pool table is leveled with a Starrett machinist's level. As I said. Just my opinion. Hope it's helpful info.
Just looked again and realized you purchased your app. For the length and width data. I'd program in your length of 24' or 288", whichever measurement the app accepts. Width is 80" or equivelent. How to do it?? Don't know. Good luck with it.
Harley Ultra Classic (Geezer Glide) Rider, Retired US Army Paratrooper, fisherman, shooter. Proud to have served, proud of those that still do, or have done so with pride.
2005 National Dolphin 34'