Comparison: More on SWBD and EVS Shorelines
Comparison: SWBD and EVS - Landsat Image (1:4,000)
Comparison: SWBD and EVS - Map (1:4,000)
My EVS mapped shoreline was digitized using the Landsat image. The datum used during construction of the EVS shoreline was WGS-84. This is the same datum used during the construction of the SWBD Shoreline.
Now for the shorelines. The EVS shoreline tracks the Landsat imaged shoreline, as precisely as possible, using on-screen digitizing and considering each pixel depicts 14.3 meters of image information. The EVS Reef Shoreline layer tracks the shallows, with breaking surf, near the island's above-water shore.
SWBD uses SRTM data. When they processed their vectors, they elected to keep pixel shapes as squares. I am sure they had an option to create the shoreline vectors using an anti-alias pixels (interpolate) that would have smoothed pixel square corners. It is a "black box" function, a software engineer's mathematical solution. I consistently use this feature to prep my imagery prior to digitizing. I know for certain the shorelines do not look like the "stairs" SWBD depicts. I prefer the "smoothed" image created by the anti-alias pixel method.
Some of the SWBD vectors lineup closely with EVS shorelines, but definitely not in this case. SWBD shoreline vectors are an interesting solution, but they definitely do not replace the precision displayed by an EVS shoreline.
