Comparison - WVS, EVS, PGS and GEVS
4-Vector Shorelines (WVS, EVS, PGS and GEVS)
Let me begin by advising that you left-click on the image and then select "All Sizes" to see this image in it's full size. This shows 4-vector shorelines. They all have their benefits. WVS is the least defined of the four. It was built from 1:250,000 Tactical Pilotage Charts and Nautical Charts. Much of the data was pre-satellite. It is good for work above 1:250,000 scale.
The PGS is shoreline data extracted from Landsat ETM+ 2000 imagery. It is a very recent entry into precise shorelines. Once the obscured shorelines are resolved it will be an exceptional vector map file of the world.
EVS is my designation for shorelines created from Landsat ETM+ 2000. I have demonstrated in previous posts that althought the PGS is a wonderful world map file it does not match to precision of EVS maps. My hand-drawn maps are some of the best made for many islands throughout the world.
Now for GEVS (Google Earth Vector Shorelines), they are a tremendous improvement over EVS shorelines. Because much of the imagery is 1-meter resolution, the shoreline plots are extremely precise. I still haven't figured out on how to incorporate other layers of information I typically digitize. As I work with GEVS I am sure I will develop a system that will allow me to capture additional layers of information, besides shorelines.
All 4-vector shoreline files work for different purposes. My island maps will still make great use of the Landsat ETM+ 2000 imagery. At times, I will execute mapping projects using 1-meter imagery. Ain't mapping fun? So many choices.
OT: Comparison
