LOW COST, ULTRA HIGH SPATIAL AND TEMPORAL RESOLUTION MAPPING OF INTERTIDAL ROCK PLATFORMS
Intertidal ecosystems have primarily been studied using field based sampling; remote sensing offers the ability to collect data over large areas in a snapshot of time which could compliment field based sampling methods by extrapolating them into the wider spatial and temporal context. Conventional remote sensing tools (such as satellite and aircraft imaging) provide data at relatively course, sub meter resolutions or with limited temporal resolutions and relatively high costs for small scale environmental science and ecology studies. In this paper, we describe a low cost, kite based imaging system and photogrammetric pipeline that was developed for constructing highresolution, 3D, photo realistic terrain models of intertidal rocky shores. The processing pipeline uses automatic image feature detection and matching, structure from motion and photo textured terrain surface reconstruction algorithms that require minimal human input and only a small number of ground control points and allow the use of cheap, consumer grade digital cameras. The resulting maps combine colour and topographic information at sub centimeter resolutions over an area of approximately 100m, thus enabling spatial properties of the intertidal environment to be determined across a hierarchy of spatial scales. Results of the system are presented for an intertidal rock platform at Cape Banks, Sydney, Australia. Potential uses of this technique include mapping of plant (micro and macro algae) and animal (e.g. gastropods) assemblages at multiple spatial and temporal scales.