Shorelines Derived from Continuous Video-Imagery at the NASA-Kennedy Space Center, Florida From August 2011 to July 2012

Step 1, camera installation: A video camera (Prosilica Digital Camera GC2450 model number: 02-2171A, 2448x2050, Gig-E, 2/3 inch CCD, equipped with a Fujinon HF16HA-1B lens) was installed inside a protective case at the Eagle 4 building near the northern boundary of the NASA-KSC (28.643436 latitude, -80.624078 longitude). The case was used to protect the camera from potentially destructive environmental conditions (for example, excessive humidity, extreme weather events, etc.). The video camera was installed at an elevation of 13.5 m and was secured onto a rail of the Eagle 4 guard tower using stainless hose clamps. See CameraSetupFront.jpg and CameraSetupBack.jpg in the SupplementalFiles.zip for photos of the camera setup. A region extending 1-km to the south of the camera was established as the region of interest for the video image observations. The ground footprint of one pixel at the edge of this range is 1.2 m in the cross-shore direction and 10.0 m in the longshore, with pixel footprint decreasing with distance closer to the camera (Holman and others, 2007). Pixel footprints beyond this range were deemed too large to resolve shoreline features of interest, thus constraining the region of interest.

Step 2, timex image product collection: During every daylight hour of camera operation, a timex image product was created by averaging pixel color intensity for all frames collected during a 10-minute time interval at 2 Hz. The camera collected 1200 frames every hour. The raw imagery, saved in uncompressed Tag Image File Format (TIFF), is unavailable in this data release due to sheer data volume and network restrictions. One timex image per day was used for analysis. For an example of a timex image, see 1271944801.Thu.Apr.22_14_00_01.GMT.2010.nasadvt1.c1.timex.jpg within SupplementalFiles.zip. The timex selected for each day was the product that was created when the tide level was closest to MHW at this location (0.23 m), based on observed water levels from a nearby NOAA station (NOAA, 2018). This was done to introduce consistency with the GPS-derived shorelines, which were extracted as the MHW contour. Each day’s MHW timex product was rectified to a horizontal map and converted to a local coordinate system, with the camera centered at the origin, using the established photogrammetric techniques outlined in Holland and others (1997). An example of the timex product converted to a world coordinate system (WGS84 UTM 17N) is available in the SupplementalFiles.zip as 1271944801.Thu.Apr.22_14_00_01.GMT.2010.nasadvt1.c1.plantimex.jpg. Additional timex products can be obtained through official request to the process contact below.

Step 3, converting from the local coordinate system to a world coordinate system: The local coordinate system was converted to the World Geodetic System of 1984 Universal Transverse Mercator 17R (WGS84 UTM 17R) coordinate system using the following method in Matlab R2010a: - param.x0 = 536739.921; % UTM coordinate of local x0, m - param.y0 = 3168540.207; % UTM coordinate of local y0, m - param.rx = -33.6777; % deg rotation - param.UTM ='17R'; % UTM zone [la,lo,utmz] = ll2utm(-80.640365, 28.585132,23) Please note that WGS84 UTM 17R is a distinct grid zone within the Universal Transverse Mercator coordinate system. Each UTM zone is segmented into 20 latitude bands. Each latitude band is 8 degrees high, and is lettered starting from the letter "C" at 80 degrees South. Each zone is lettered onward in the alphabet in 8 degree increments (omitting letters "I" and "O"). The combination of a zone and a latitude band defines a grid zone. In a grid zone, the zone number is written first (for example, 17), followed by the latitude band (for example, R). The grid zone serves to delineate irregular UTM zone boundaries and enhance positional accuracy. For the shoreline data (.txt) included in this data release (Williams and others, 2021), all data points were converted into UTM grid zone 17R from the local coordinate system using the conversion above. For more information on UTM grid zones, please refer to https://apps.dtic.mil/sti/pdfs/ADA247651.pdf. When trying to convert the shoreline data (NASA-KSC_shorelines.txt) into a GIS file (such as a shapefile [.shp]), please note that the data is projected to grid zone WGS84 UTM 17R. Most GIS programs (for example, Esri's ArcGIS desktop applications) will only allow users to project data into grid zone UTM 17N. The re-projection of the data in a GIS program from WGS84 UTM 17R to WGS84 UTM 17N should not produce any significant positional inaccuracies to the data.

Step 4, deriving shoreline position: The shoreline was manually identified as the wet-dry line within the region of interest of each available timex product between August 8, 2011 to July 24, 2012 (352 days). However, timex products were not available for roughly half of this timeframe due to camera malfunctions, adverse weather conditions, and/or a lack of daylight during the timing of MHW. Data gaps were filled by linear interpolation of shoreline positions at each alongshore position using methods described in Fairley and others (2009), implemented in Matlab (R2017) and written to text files with at least 3 decimal place precision for the horizontal data. For more information on this method, please see Fairley and others (2009).