I have created a new iPhone application - Site Survey - which uses the iPhone camera and standard size targets to measure distance from iPhone to target. Once target is fixed heights and widths can be measured on the same plain. Accurate for measurements of over 30 metres - 100 feet. Very useful for finding out the height of a tree or hedge, the dimensions of a room, height of a building or the size of a garden plot. Please try and all reviews welcome. For Site Survey website - description and video - www.sunmoresystems.com Rob Dewhurst