Is it possible to get the height (Z location) of an iOS device based on sensor data? I've continuously added the accelerometer data up to infer the location but it results in a cascading error, and the inferred location of the phone "drifts" when the phone is placed still. I want to build an app where users measure the height of something by first zeroing the phone on the floor and then raising the phone to the height of the object, like placing it on the table.

A few versions of iOS ago, the stitching algorithm for panoramas was updated, which produces results that in my opinion look less good for what I'm using the panoramas for. I was exploring developing a custom panorama app but couldn't find the API for taking panoramic photos, much less stitching them. Is there an API in AVFoundation or elsewhere to use for capturing a panoramic photo and stitching it?