Thoughts - Mapping Malta and Marine Shoreline Classifications
Malta - DigitalGlobe Image from Google Earth (1-50,000)
The first part of this post is called "Mapping Malta". Not necessarily a big island, but the shoreline has been quite a challenge to digitize. I am about 3/4's finished with the first pass using DigitalGlobe's imagery from Google Earth as my base and the digitizing capabilities of GE to map the shoreline. In the process, I have mapped moles, groins, breakwaters, quays, piers, slipways, ramps and a few dry docks. Thanks to DigitalGlobe's fantastic imagery, my shoreline mapping challenge is greatly magnified. But that's okay. Once this shoreline is finished, it will be a WOW!
Malta - DigitalGlobe Image from Google Earth (1-6,250)
Malta - DigitalGlobe Image from Google Earth (1-3,125)
Malta - DigitalGlobe Image from Google Earth Detail Shoreline (1-2,500)
The three detailed shoreline images above are extracted from the southern side of Malta. The coast appears to be made up of a base rock layer that sea and air manages to split apart and gradually weather these rocks into pebbles after many, many years. The rocks on the last images are very large. The rectangular-shaped boulder is over 17-meters by 17-meters! If that rock were in the sea, alone, it would be an island. Based on my mapping criteria, it is part of the shoreline. How should I classify this portion of the Malta shoreline? Rocky? That doesn't do it justice. Big Rocky? Better. Lots of Really Big Rocks Scattered Within 100-Meters of the Unfragmented Shoreline? Now, I like that name. I will work on the nomenclature to transform "wordy" into a succinct EVS label.
Malta - Landsat Image N-33-35_2000 Detail Shoreline (1:2,500)
I couldn't leave this post without giving you Landsat ETM+ 2000's comparable image of the same shoreline area. Digital Globe's HiRes imagery is amazing, from a mapper's perspective. The most accurate global shoreline freely available, NGA's Prototype Global Shoreline (PGS), approximately tracks the Landsat ETM+ shorelines. It is an impressive effort that will be useful in a wide variety of projects. But when you compare it to Digital Globe's derived shorelines - Forget about it! As you would expect.
Enjoy!
Labels: DigitalGlobe, EVS, Global Shorelines, Landsat, Malta, NGA, PGS
