Thoughts - Kaukura Atoll's 16 EVS Layers
Kaukura Atoll's EVS Layers
This post is all about EVS layers of information. You might want to pause it between slides and read my notes below the first time through. The next time, view it at a faster speed. So lets discuss the various layers used on this island.
The first 3-slides are for orientation purposes. Kaukura Atoll is located in the Tuamotus. It is a medium sized atoll.
Slide 4 - EVS Ocean Mask - I always place the atolls onto an ocean mask. Marplot has either a white or black background. Both not very practical to display an island on.
Slide 5 - EVS Shoreline - My shorelines were extracted from Landsat imagery. This layer is one of my core layers. It is the reason I make maps in the first place.
Slides 6 & 7 - EVS Land Island & EVS Airfield - The Land Island fills out the island giving it some land to view. If the island I am mapping is high, often this is the only additional land layer I will include, since I do not include elevations.
Slides 8 thru 13 - EVS Vegetation Layers - Althought the identification of vegetation from Landsat is relatively easy, to determine the density of that vegetation is difficult. My EVS Vegetation layers are as consistently identified as I am able to visually do. One of the difficult layers is the EVS Vegetation Wetlands. These tend to show up as a darker shade of green on the base image.
Slides 14 & 15 - EVS Land Bare & Land Sand - These layers define vegetation free areas. Land Bare is darker colored whereas Land Sand is most often white to shades of white.
Slides 16 thru 20 - EVS Reef Layers - The challenge with reefs is to determine depth of water based on what is visible. The reef that is lighter in color I classify as EVS Reef Shallow. As the color of the reef gets darker, I attempt to delineate logical divisions between various depths. My final reef is called EVS Reef Deep which is the darkest area within the lagoon.
These are some of the decisions I have to make as I construct my maps of islands. I strive for consistency and as clean and sharp a delineation as possible between layers.
Enjoy!
