How do you measure light levels in a space?

Goni is our response to a problem faced by designers of all types around the world; how do you measure light levels in a space without carrying huge, expensive kit with you?  By using the tools available within an iPhone our Goni software can capture light levels and create a 3d light map of a space, which can then be imported into standard lighting design programs; it enables lighting designers in particular to create instant 'snapshots' of a found environment, collecting ambient light levels during what can be small windows of opportunity on a site visit.  It can alternatively be easily set up to monitor light levels throughout the day and night.