BUILDING A POST-SANDY DATABASE OF GROUND LEVEL PHOTOMOSAICS OF THE BLOCK ISLAND BLUFFS USING GOOGLE DRIVE, SPREADSHEET MAPPER AND GOOGLE EARTH

The objective of our research was to compile ground-based photographs of the bluff shorelines of Block Island, RI following Superstorm Sandy. Superstorm Sandy made landfall in New Jersey 213 km (194 mi) south west of Block Island on October 29, 2012. Significant wave heights during Sandy exceeded 9 m (31ft) at a buoy southeast of Block Island (with the largest individual waves > 14 m (47 ft). Coupled with a1.5 m (5 ft) storm surge, Sandy caused extensive erosion along parts of the island. Photos were taken from the beach at >400 sites along the entire perimeter of Block Island. Spatial location of the photographs was recorded using a Trimble Juno Global Positioning System (GPS) with ~5 meter accuracy. Following the field collection, the photographs for each field station were combined into a mosaic using editing tools and automated processes within Adobe Photoshop CS10. Of the >400 stations, ~155 stations have been completed along the island’s bluff shoreline.

The mosaics are then served on the web, and the URL of each photo is linked to the GPS position of the photograph in a Spreadsheet Mapper Excel Template stored on a Google Drive. This spreadsheet is linked to a Google Earth *.kml file, and serves as a virtual-tour of each field site. The advantage of this technique is that once the mosaics are served on the web, only the *.kml is downloaded (< 10 kB). Individual mosaics are called up when a user clicks on a field site in Google Earth.

Our hope is that by presenting the data in this manner it will be accessible for outreach and as a scientific tool to document bluff erosion on the island. This work is part of a wider project to examine bluff erosion on Block Island at various timescales. The heterogeneity of the bluffs, ranging from Cretaceous-Tertiary aged Coastal Plain strata to Late Wisconsinan glacial till and stratified deposits produces a complex response to storm events.

These photographs are currently being compared to field measurements and remote sensing datasets, and stations can be reoccupied to photograph the bluffs following a future storm event to evaluate changes to the bluff. The overall technique remains a relatively low-effort way of sharing images for a field site, providing a low-cost (free), easily downloadable virtual fieldtrip.