Sand Areas for the Undeveloped Areas of New Jersey's Barrier Islands, Extracted from Orthoimagery, March 9, 1991, to July 30, 2013

Assessing the physical change to shorelines and wetlands is critical in determining the resiliency of wetland systems that protect adjacent habitat and communities. The wetland and back-barrier shorelines of New Jersey changed as a result of wave action and storm surge that occurred during Hurricane Sandy, which made landfall on October 29, 2012. The impact of Hurricane Sandy will be assessed and placed in its historical context to understand the future vulnerability of wetland systems. Making these assessments will rely on data extracted from current and historical resources such as maps, aerial photographs, satellite imagery, and lidar elevation data, which document physical changes over time. This USGS Data Series publication includes several open-ocean shorelines, back-island shorelines, back-island shoreline points, sand area polygons, and sand lines for the undeveloped areas of New Jersey's barrier islands that were extracted from orthoimagery (ortho aerial photography) dated from March 9, 1991 to July 30, 2013. This data-set consists of polygons that represent the sand areas found in orthoimagery taken on the date specified in the filename and in the "Date_" field in the feature attribute table. Orthoimagery of New Jersey were acquired in digital format from U.S. Department of Agriculture (USDA), U.S. Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), and New Jersey Geographic Information Network (NJGIN). Prior to processing, the images were trimmed to remove the bulk of the areas that were not going to be analyzed. Using ERDAS Imagine 9.3, the images were classified into 40 classes that were coded as either sand or not sand. Due to varying conditions within the imagery, the coding occasionally varied from one area to another. Using ArcGIS 10.2, the resulting coded raster data-sets were converted to polygons and edited. The following list provides additional details about the orthoimagery used. The sand areas for each date and area is in a separate data-set (shapefile) named nj_sandpo_<range of dates>_<area name>.shp. The orthoimage date for each polygon is included in the shapefile attribute table's "Date_" field. Date Type Source Resolution 19910309-19910313 Pan USGS, DOQQ 1 m (meter) 19950325-19950407 CIR USGS, DOQQ 1 m 20020218-20020411 CIR NJGIN 1 m* 20060805-20060613 Natural USDA, NAIP 1 m 20070318-20070415 Natural NJGIN 1 m* 20080808-20080826 Natural USDA, NAIP 1 m 20100703-20100726 Natural USDA, NAIP 1 m 20120314-20120416 RGBI NJGIN 1 m* 20130707-20130730 Natural USDA, NAIP 1 m Pan - Panchromatic (1 band, gray scale) CIR - Color Infrared (infrared, red, green) Natural - Natural Color (red, green, blue) RGBI - Natural Color and Infrared (red, green, blue, and infrared) DOQQ - Digital Orthophoto Quarter Quads NAIP - National Agriculture Imagery Program *Resampled from 1-foot resolution imagery then smoothed using a 3 pixel by 3 pixel focal mean.