EVS-Islands

Gavdos and Gavdopoula Islands - Map

Ever since I began using the Prototype Global Shoreline (PGS) map files in place of World Vector Shoreline (WVS), I find reason to compare it to my Enhanced Vector Shorelines (EVS), which makes up the shorelines of all of my maps.

Gavdos Island - Map (Detail EVS vs. PGS)

The PGS shoreline is the dark blue line and the EVS shoreline tracks the island shape. This map is shown at 1:10,000 scale. At this scale the PGS does not closely track the Landsat shoreline. It is a problem with the parameters of the original mapping algorithm used by EarthSat when they constructed the PGS shoreline. At a scale of 1:125,000 the PGS and EVS appear to track each other with a great deal of precision. It is when you zoom into the finer scales that PGS tracks less and less precisely.

PGS needs to become the ultimate global shoreline map file. It is derived from Landsat 2000 imagery. Consequently, it should track shorelines as consistently and precisely as possible. Although it is close, "no cigar" yet. PGS should track shorelines as consistently and precisely as EVS is able to do. Will it ever?

More about this topic later.

Posted by Mr Minton at 7/13/2006 09:03:00 AM | Permalink | Comments | links to this post

Why do I make maps of islands? Most likely because I would like to make a protracted visit to an island. An island is off the beaten path. An island can provide a simpler lifestyle. All of these are good reasons, but my reason is still being determined. However, according to an article published in the Mirror.co.uk, the No. 1 best place to live in the world is ... Vanuatu. The South Pacific still offers a strong allure.

Posted by Mr Minton at 7/13/2006 06:26:00 AM | Permalink | Comments | links to this post

Nukuoro Atoll - Detail of Southern Motus with Names

Nukuoro Atoll - Detail of Northeastern Motus with Names

There are 46-named motus on Nukuoro Atoll. All of these names are found in the previously cited Atoll Research Bulletin #107 (see above post for link). You will need to select the image which will take you to my Flickr account, select "All Sizes" and you will be able to read all of these labels.

Posted by Mr Minton at 7/11/2006 11:37:00 PM | Permalink | Comments | links to this post

Nukuoro Atoll - Image (N-56-00_2000)

Nukuoro Atoll - Map

Nukuoro Atoll - Shuttle Image (ISS013-E-28610)

Nukuoro Atoll (3˚50'N., 155˚00'E.) consists of more than 40 islets, about 3.6m high, standing on the E side of the barrier reef. Nukuoro, an island covered with palm trees and tropical plants, is the center of activity. A small pier is situated on the lagoon side of Nukuoro, which is reported to be unsafe, even for small vessels. There is a radio station on the island.

Nukuoro Passage, 27 to 37m wide, leads into the lagoon be-tween the reefs fringing the islands of Kaujema and Shenukdei. The passage is deep and is marked by tree branches stuck into the reef, but is fronted by a bar, with a least depth of 8.2m. Numerous coral patches, some of which dry, are scattered throughout the lagoon.

Caution.—The sea is usually high at the bar and becomes choppy when the tidal currents are strong. These currents sometimes attain a velocity of 6 knots on the ebb. In 1978, the passage was reported to have sufficient depth for small boat operations, but it is very narrow and has an uncharted bend of 45˚. The passage should only be attempted at slack water, by small vessels with local knowledge, under the most favorable of conditions.

In 1985, a vessel reported that anchorage within the vicinity of the passage was impossible.

(SD Pub-153)

I have located one excellent source, Atoll Research Bulletin #107. It is a discussion of the place names found on Nukuoro Atoll. It turns out that the language of the approximately 900 people living on the island is unique to the island. This scholarly discussion will give you insights into not only the peculiarities of the Nukuoro-ian language, but also contains a map with names for all of the 46 motus.

And finally my inspiration for doing this map, NASA Earth article about Nukuoro Atoll. I used this image to fine-tune my map. This image shows the reef as a sandy bottom. Landsat ETM+ displays the reef in their classic blue color. Since the shuttle image dates to very recent, my suspicion is that the reef is sandy. It appears to be above water, as well. I depict it as EVS Reef Shallow.

Posted by Mr Minton at 7/11/2006 08:58:00 PM | Permalink | Comments | links to this post