EVS-Islands

What is EPIP?

Enhanced Vector Precision Island Polygons - Using Landsat ETM+ ortorectified image mosaics as my base images, I digitize various layers of information, most typically from islands. I use Landsat ETM+ because: 1) It is free. 2) It is typically cloud-free. 3) It is consistent in quality. 4) It covers the earth. 5) It is virtually copyright free. This is the degree of precision over 8,000 South Pacific island polygons have been digitized to. This level of digitizing precision over such a broad expanse (South Pacific) is quite an accomplishment. What does this level of digitizing precision entail? What are the layers of information being captured?

Atoll Digitizing - First Layer Vegetation (Hi-Lo)

The first layer I digitize is vegetation. Working at a scale of between 1:25,000 to 1:15,000, I carefully digitize layer outlines. Working with the vegetation layer, I have been known to make a number of vegetation classifications. For the purposes of EPIP, I make one classification - Vegetation (Hi-Lo). This broad classification focuses primarily on land vegetation. I am reasonably certain I digitize some patches of reef vegetation as well.

Atoll Digitizing - Second Layer Island Polygon

My second layer of information is the island polygon. As the name implies, this should be any above-water land feature. When digitizing an atoll made up of many small motus located on a complex reef that is often awash the difference between above-water, reef awash and below-water can get fuzzy. It is within this layer that I am certain I include reef features that are either awash or just below water. In this layer, I prefer to digitize too much as opposed to too little. Perhaps the next generation of Landsat imagery will allow for a clearer land vs reef determination. Until then, I'll digitize in as consistent a manner as possible.

Atoll Digitizing - Third Layer Reef Shallow

This is another layer that I have used a number of classification. For the purposes of EPIP, whatever is visible (shade of blue) that I have not classified as a island polygon, makes up my Reef Shallow layer. This layer on the outer reef edge is typically defined by waves and/or a faint blue area along the shore. The inner reef shore also contains this blue area in varying shades and thicknesses. All of these blue areas are classified as Reef Shallow for the puposes of EPIP.

Atoll Digitizing - Fourth Layer Reef Deep

The final layer is Reef Deep or the central lagoon. It is basically everything within the atoll that isn't an island polygon or reef shallow. A crude classification, but it works well for EPIP.

I do all of my digitizing using Global Mapper. It is: 1) dependable 2) fairly inexpensive 3) simple to use 4) produces consistent product and 5) is serviced by Mike, absolutely the best customer service/owner of a product.

Atoll Digitizing - EPIP's Four Atoll Layers

And there you have it, EPIP's four atoll layers in all their glory. I'll share a few of my recently completed atolls with you. North is up and I realize they are unfinished maps without lat/lon, titles, north arrow and such, but they make the point, EPIP is a quality product.

Tahanea Atoll - EPIP (1:200,000)

Motutunga Atoll - EPIP (1:100,000)

Tunake Atoll - EPIP (1:50,000)

Tepoto Atoll - EPIP (1:25,000)

Enjoy!

Labels: atoll, EPIP, EVS Precision, French Polynesia, Global Mapper, Landsat ETM+, Tuamotus

Posted by Mr Minton at 7/16/2008 08:55:00 AM | Permalink | Comments | links to this post

Reao Atoll - ISS004-E-12987, 12988, 12989 Images (1:100,000)

Reao Atoll - Other Precision Map - Source ISS004 Images (1:100,000)

This is my finished shoreline map of Reao Atoll FP. The imagery covering this atoll is of sufficient detail that other layers of information can be digitized, if I wish. For now I just want to complete shorelines within the Tuamotus at EVS precision or better.

Enjoy!

Labels: atoll, EVS Precision, ISS Image, Pacific Ocean, Polynesia

Posted by Mr Minton at 6/21/2008 08:53:00 AM | Permalink | Comments | links to this post

View Larger Map

Zoom In to See Pukaruha and Reao Atolls

Reao Atoll FP - ISS004-E-12987, 12988, 12989 Images Modified (1:75,000)

For whatever reason Landsat ETM+ does not have a mosaic that covers Reao Atoll. Google Earth has Landsat imagery, but no imagery for this area at the NASA site where I download my Landsat ETM+'s. As I am making all of my maps without using DigitalGlobe imagery, because one day I might want to sell my shorelines, I must locate other imagery sources. The International Space Station (ISS) is a source of sometimes excellent imagery. And, in fact, ISS004 has 3 cloud-free, highly detailed images covering Reao Atoll, my current target project.

I downloaded, modified their sizes, constructed a "whole atoll" mosaic, rotated the image to align it with my base island shoreline vectors (NGA PGS vectors) and georectified this image using 7 GCPs.

Reao Atoll FP - Other Precision Mapping on ISS Images - Finished Motus (1:40,000)

Reao Atoll FP - Other Precision Mapping - Finished Motus (1:40,000)

Once I had a georectified image, my digitizing could proceed. I decided to map motus first, thus the title of this post. Motu mapping is quick, repetitive and gives one a sense of completion. Each motu is actually a small island. Reao Atoll will ultimately be made up of a 100 or more islands. The two above images show the results of about 2-hours worth of digitizing. I always strive for EVS precision, Landsat ETM+ resolution or better. This imagery allows me to exceed EVS precision. For mapping quality purposes, I label it as Other precision and label it's Source attribute as ISS-Hi Res. I have completed 58 Other precision island polygons. Let's look at the challenges one encounters as they map motus.

Reao Atoll FP - Other Precision - Digitizing Motu (1:10,000)

First, I am working at 1:10,000 scale. At this scale, I am able to maintain sharp feature clarity. In addition, this resolution allows me to make consistent shoreline determinations that will work with the scale of my finished map, between 1:50,000 to 1:25,000. My mapped shorelines consist of actual or suspected (based on color) above-water features. Sounds easy enough to consistently identify, but it isn't. After mapping a few thousand motus, I have learned to make a color(s) to shoreline decision and rigourously adhere to that definition. In imagery, color is god.

In the Reao Atoll image, the motu shorelines are identified as a white sand color. Having studied enough hi-res 1-meter imagery of reefs and motus, I know that between motus are features called hoas. These serve as channels allowing water to flow in and out of the lagoon. Eventually, these hoas fill up with coral rubble and sand, vegetation takes root and motus join motus to form a continuous land ring around a lagoon. Given enough time, the lagoon quite often fills in and, sea level cooperating, a flat island forms where an atoll once stood. Using my white sand color as my motu shoreline, I began digitizing.

Reao Atoll FP - Other Precision Mapping - Finished Motu (1:10,000)

If I do a good job, my project consists of a series of motu shorelines. The digitizing is monotonous, eye-straining and lately, my feet hurt because my chair is uncomfortable. But the finished map is what I work for. I'll share it with you when I've finished. Until then...

Enjoy!

Labels: atoll, DigitalGlobe, digitizing, Global Mapper, ISS Image, Landsat ETM+, motu

Posted by Mr Minton at 6/20/2008 07:58:00 AM | Permalink | Comments | links to this post

Nukutavake Atoll - EVS Precision Map (1:25,000)

The second map is the new and improved version of my EVS Precision island maps. Not only have I made better use of the text fonts found in Marplot, but I've added a North Arrow. Also, and most important, I've adjusted the colors. I promise that any of you creating a large body of original maps will find yourselves constantly tweeking the colors. This particular color pallet is probably version 101. Seriously, colors are the ultimate subjective layer of information one places on a map. Quite often they reflect your moods. If you are having a bad day, wierd colors result and a good day leads to peaceful earth-tone pastels.

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Nukutavake Island (Noukoutawake) is a small island, of coral formation, located about 8 miles NW of Pinaki. It is about 3 miles long in an E-W direction, and is wooded except at its E end. There is a radio station on the island.In May, June, and July the population of this atoll moves to Vairaatea, and in August, to Pinaki to harvest copra.

(SD Pub-126)

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Group: Centre East Group Archipelago: Tuamotu Archipelago Country: France - French Polynesia - Tuamotu Is. Region: Oceania 18 Lat: 19.28º S Long : 138.78º W Area: 4.5 sq. km Altitude: ? m Depth to nearest land: 3000 m Nearest island: 14.5 km @ 143° (Atoll Pinaki) Group: 980 km Nearest continent: South America Distance: 5400 km Isolation Index: 108 ISLAND TYPE: low coral Natural Protection Indicator: 2 CLIMATE: tropical CATASTROPHIC THREATS: cyclones Threat Indicator: 1 ECOSYSTEMS: Coconuts; fringing reef Number of Ecosystems - Terrestrial: 1 Marine: 1 Percent shoreline: Coral Reef: 99% Mangrove: 0% HUMAN OCCUPATION: Uninhabited, ? Population: 0 Density: 0.0 persons/sq. km Major Human Activities: coconut plantations Percent population in agr/mining/fishing: 17% Human Threat Indicator: 1 Gross Domestic Product: $ 7236 per capita Economic Pressure Indicator: 4 DATA RELIABILITY: Data Rel. Indicator: 1 HUMAN IMPACT INDEX HI: 5 CONSERVATION IMPORTANCE INDEX CI-Terrestrial: 5 Low CI-Marine: 4 Low Last updated: 27/02/89

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Nukutavake (aka Queen Charlotte Island) is an atoll located in the eastern part of the Tuamotu Archipelago at 138°48’ west longitude by 19°17’ south latitude. It is 1,125 kilometers (699 miles) from Papeete. British Captain Samuel Wallis was the first European to discover this atoll in 1767. This is a unique atoll because although it is flat and of coral formation, it has no lagoon. While some accounts claim there are no signs of there ever having been a lagoon, other accounts claim that what was once a lagoon has been entirely filled in by sand and limestone particles from the external coral reef. Part of the atoll is covered by dense vegetation, while the rest has a coconut tree plantation covering some 800 hectares (1,977 acres). Nukutavake is 5.2 kilometers (3.2 miles) long. Its width ranges from 450 meters (1,476 ft.) to 1.3 kilometers (0.81 miles) in the director of the village. The atoll covers an area of 360 hectares (890 acres).

The village, located in the northeastern part of the atoll, has some streets and a main road from the coast and the coconut plantation. There is an aerodrome 800 meters (2,625 ft.) south of the village, linking the atoll to the outside world. There is a whaleboat dock opposite the village that allows for transferring people and cargo from and to cargo ships that anchor offshore. The 1996 census recorded a population of 196 persons. The atoll is the administrative center for a district made up of the associated districts of Vahitahi and Vairaatea.

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This island was mapped quickly. Not carelessly, but quickly. It took about 1-hour to digitize and create the map. Another 30-minutes to post and comment.

Also, the discovery of the additional island information from the web site of the President of French Polynesia (what a job!) will enhance the information associated with this island. I did send him an email to present my website. However, no reply as yet.

Enjoy!

Labels: atoll, EVS, Global Mapper, island, Landsat, map, Marplot, Pacific, Polynesia, Tuamotus

Posted by Mr Minton at 2/03/2008 09:45:00 AM | Permalink | Comments | links to this post

Nikumaroro Atoll - Landsat Image S-01-00_2000 (1:31,250)

Nikumaroro Atoll - Marplot Map (1:31,250)

A year ago I thought this was a solid mapping effort. I had used both Landsat and the ESA Ikonos image (04-2001) as base images from which I constructed my map. My color choices were still not finalized, but the composition and layout were satisfactory. How things have changed in a year!

Nikumaroro Atoll - ESA Ikonos Image (04-2001)

Nikumaroro Atoll - Marplot Map (1:30,000)

With this new revision, I worked exclusively off of the ESA Ikonos image (04-2001). Using Global Mapper, I georectified the image and digitized all of the layers of information from it. I selected my layers and colors within Marplot where I assembled my "nearly" complete map. I viewed it in Irfanview. Satisfied with my preliminary efforts, I moved the map into ImageForge, a freeware drawing program, to add all of my fancy stuff - Legend, Title box, modified Lat/Lon grid, North Arrow. I previewed the map once more using Irfanview. Satisfied with the mapping effort, I uploaded the image into Flickr and posted it into Blogger. As a result of this time, effort and skill all of us ended up with this exquisite map of Nikumaroro Atoll.

View Nikumaroro Atoll on Google Maps

Enjoy!

Labels: Amelia Earhart, atoll, EVS, Flickr, Gardner Island, Global Mapper, Ikonos, ImageForge, IrfanView, Kiribati, Landsat, Marplot

Posted by Mr Minton at 7/13/2007 01:34:00 PM | Permalink | Comments | links to this post

Nikumaroro Atoll - Marplot Map (1:30,000)

This is my third time posting this. I received an e-mail from a representative of TIGHAR, a group that has visited this atoll searching for clues to the whereabouts of Amelia Earhart. He asked that I post the following information to discourage visits to the island. The only way one is allowed to visit is with permission of Kiribatian authorities. Read on.

"The best landing place, marked by a white pyramidal concrete structure, is about 0.3 mile S of the village. A boat channel has been cut through the reef in a 054˚ direction and in line with the concrete beacon. Landing should be attempted just after HW when there is less surf than on a rising tide. With a SE wind, landing can be effected in the lee of the wreck at any stage of the tide."

(Sailing Directions Pub-126)

Comment from Pat Thrasher at TIGHAR: The beacon is long gone. It was cleaned off by a storm in 1990 or so. The wreck is gone except for the shell of the triple expansion steam engine. No lee.

BUT. It is completely, utterly ILLEGAL for anyone to land there at all. It is a protected area, bird sanctuary, and about to become a World Heritage Site. No fishing, no landing, no nothing, except as sanctioned by the government of the Republic of Kiribati. We have permission and will have a Customs officer with us. No equipment may be landed without strict adherence to environmental concerns about introduction of insects, bacteria, molds, etc.

Nikumaroro is a sensitive archeological and cultural site. I hope you will discourage landings rather than promoting them with information about when and where to make them!

Nikumaroro Atoll KR

Nikumaroro Atoll (Gardner Island) (4˚40'S., 174˚31'W.) is a wooded, wedge-shaped atoll lying about 137 miles W of Orona Atoll (Hull Island). The atoll is surrounded by a fringing reef, which dries at LW, extending about 0.2 mile offshore. The NW and SE extremities of the reef appears to be extending. Depths off the atoll, which is steep-to except at its NW and SE extremities, average 366m, 0.3 mile from the reef. Nikumaroro Atoll (Gardner Island) encloses a lagoon into which there is no navigable passage. With the exception of two breaks, a large one on the W side and a narrow one on the S side, the land rim of the atoll entirely surrounds the lagoon.

The lagoon is encumbered with coral heads, but seaplanes have landed successfully.

A conspicuous stranded wreck lies close W of the N extremity of the atoll. The wreck was reportedly breaking up.

Tides—Currents.—Off the atoll the set is W, and varies in direction and strength with the prevailing wind. Close inshore, the current follows the trend of the land to the W. There is a deserted village on the W side of the atoll, about 1 mile S of the N extremity, off which anchorage may be obtained by small vessels, very close inshore. Two small beacons N of the village indicate the approach.

Directions.—The best landing place, marked by a white pyramidal concrete structure, is about 0.3 mile S of the village. A boat channel has been cut through the reef in a 054˚ direction and in line with the concrete beacon. Landing should be attempted just after HW when there is less surf than on a rising tide. With a SE wind, landing can be effected in the lee of the wreck at any stage of the tide. The reef is extremely slippery and wide, and the landing is not recommended if any equipment is to be landed or brought off. (SD Pub-126)

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This is a redo of a previous post dated 2/25/2006. I wanted to bring in my current colors and include the standard images and maps (1:200,000, 1:100,000, 1:50,000 and 1:25,000). In addition, I wanted to show the Ikonos image that was used to help in digitizing the vectors that makeup this map.

If you have difficulties reading the Flash presentation, go directly to my Flickr account and check out the set of images with the same name as the title of this post.

Enjoy!

Labels: Amelia Earhart, atoll, EVS, Gardner, Ikonos, island, Kiribati, Landsat, map, Marplot, Pacific

Posted by Mr Minton at 7/02/2007 09:55:00 PM | Permalink | Comments | links to this post

Basis Motu on Chuuk Atoll

Pacific Biodiversity Information Forum has made available a collection of photographs taken throughout the Pacific by Dr Angela Kepler and Dr Cameron Kepler. I counted 2943 photos on their website. It should be noted, they make all of these photos available copyright free. It is truely a photographic treasure of islands and island life. I will include a few of my favorites below.

Falalu Motu on Chuuk Atoll

What a story! This is the small island many of us pictured ourselves upon, managing to survive after the shipwreck. Now that we are older and wiser we know that anything short of an afternoon spent on an island of this size is too long of a time.

Homestead on Oroluk Atoll

This homestead is the only habitation on this motu within Oroluk Atoll. The family fishes, grows food and lives a very simple life. This is the island I wouldn't mind being stranded on.

Starbuck Island Interior

I always knew that Starbuck Island was one of the dry islands within the Pacific, having the misfortune to be located where rain doesn't fall. I wouldn't mind visiting for a day and leave. This island would not provide a great deal of sustanence for us big humans.

Tribulus Stickers on Sandals

And finally, one of my favorites. This is one of the realities contrasting with our image of a balmy, beautiful tropical isle - stickers! I've heard the stories of bugs that bite, stickers that stick, reefs that cut and food, strange to our western tastes. This picture is a reminder that these islands, we love so much, have a tough edge to them. Hopefully, the worst that you will encounter on your next visit to a tropical island paradise is Tribulus Stickers on your sandals.

Enjoy!

Labels: atoll, fauna, flora, island, Pacific Biodiversity Information Forum

Posted by Mr Minton at 6/28/2007 04:56:00 PM | Permalink | Comments | links to this post

Egmont Islands BP

This is going to be my last project for awhile. I need a break for a few weeks from the demands of creating unique maps, researching and posting information about my projects. I have been spending way too much time with my PC and not enough time with the people I love.

Enough said.

Now about Egmont Islands. I feel this map is exquisite. It marks the first time I've mapped coral heads. They were a challenge to digitize and map, but ultimately they turned out nice. The vegetation layers were approximately mapped. All of the different layers of this map were well done. This map is useful at scales as large as 1:12,500 to 1:6,250.

Just a brief note on the recent history of this group of islands. They are part of the British Indian Ocean Territory (BIOT). The most well-known island within the BIOT is Diego Garcia. Egmont Islands, located 60-kms from Diego Garcia, at one time had a population of 60-people. Today, the Egmont Islands are uninhabited. There is a remnant coconut plantation on the three larger islands. Eventually, it is hoped that the islands will revert back to their natural state. That is one of the alleged reasons the indigenous population was removed from all of the islands in BIOT. A judge in England has since ruled that the forced removal was illegal and if the original inhabitants want to return to their island homes, they can. However, when they try to return, they are turned away by the major leasee operating out of Diego Carcia - the United States military.

I am not sure there is a mutually agreeable solution. The US military will keep unwanted inhabitants away from these islands as long as they deem it necessary. In the meantime, these pristine islands are gradually reverting back to their natural state. Good for them, bad for the Chagossians.

view Egmont Islands on Google Maps

Enjoy!

Labels: atoll, BIOT, Digital Globe, Indian Ocean, Landsat, map

Posted by Mr Minton at 4/18/2007 11:15:00 PM | Permalink | Comments | links to this post

Pukaruha Atoll FP

Pukaruha Atoll is off the beaten path. It lies at the eastern limits of the Tuamotus. At the northern end of the main motu is a village. An airstrip is located in the middle of the main motu.

Now for the real scoop. Artistically this is my best map and most detailed. It is constructed of close to 1,000 unique polygons making up the various layers of infornmation. I used Digital Globe imagery found in Google Earth to construct this map. The imagery is 1-meter resolution and I mapped the hell out of it! The project took about 20 hours.

Frequent visitors know that I primarily work off of Landsat ETM+ 2000 mosaic imagery. This island and it's neighbor are not covered in the available Landsat imagery. I am sure that it was a fluke that this mosaic was not made available to the public. However, I wanted to map it. So I checked out the imagery on Google Earth and found this Digital Globe base imagery.

The resulting map work is exquisite. My work on the lagoon's reef is a work of art and it is accurate.

For those of you that just want to see my latest project, this is it.

For those of you that appreciate a gorgeous map, this is it as well.

view Pukaruha Atoll on Google Maps

Enjoy!

Labels: atoll, EVS, Global Mapper, island, Landsat, map, Marplot, Pacific, Polynesia, Tuamotus

Posted by Mr Minton at 4/06/2007 06:10:00 AM | Permalink | Comments | links to this post

Kingman Reef US

Kingman Reef is a US Minor Island Possession. Reefs are curious structures. If they qualify as above water islands, they enable a country to control a 200-NM Exclusive Economic Zone (EEZ) and that is alot of potential resources to control. If the reef is a below-water, it is merely a hazard to navigation and an interesting spot for scientists and surfers. Kingman has a small strip of cobbled land that rises 1-meter above sea level. During any sort of stormy conditions, Kingman Reef is below water or, at best, a reef awash. However, during calm weather, Kingman Reef supports a sliver of an island making it EEZ elgible.

In 1983, President Ronald Regan declared Kingman Reef and Palmyra Island an EEZ of the United States. As stated above, EEZs represent potential riches for the country controlling them. The last image in the above pictobrowser shows the results of a USGS project to catalog the EEZs of the United States using GLORIA sidescan-sonar imagery. It shows the sea floor in the area of Kingman and Palmyra. All of this area is controlled by the United States. We are not alone in our quest to control underwater real estate. All nations with access to a shoreline are in the EEZ business. Even if they don't work the real estate, others will pay them dearly to mutually benefit.

Finally a comment about my image that compares a World Vector Shoreline (WVS) and my own Enhanced Vector Shoreline (EVS) of Kingman Reef. One of us is off, way off! And it isn't me! The WVS shows a reef that is about 28-miles N/S by 60-miles E/W. My EVS depiction of Kingman Reef shows it to be 5.5-miles N/S by 9-miles E/W. My product was created using Landsat ETM+ imagery whereas the WVS was created off of God knows what, by who knows what. The WVS vectors are grossly enlarged and misplotted

Now for the "wasted money" part. I think it is ironic that an enlarged misplot could cost money. I looked at cataloged imagery held by Digital Globe. It turns out that someone, probably NIMA or Navy, had the enlarged WVS area imaged. Kingman Reef is covered by three Digital Globe images. The Digital Globe sequence of images encompassing the misplotted WVS Kingman Reef consists of at least 60 images. At about $1,500 an image a big chunk of deep ocean was studied. The imagery alone would have cost $90,000. It appears someone commissioned the satellite imaging of a vector misplot! Somebody spent good money to determine the extent of bad mapping. Seems like bad business to me.

Enjoy!

Labels: atoll, Digital Globe, EVS, island, Landsat, Line Islands, map, Marplot, Pacific, reef

Posted by Mr Minton at 2/18/2007 05:30:00 PM | Permalink | Comments | links to this post

Palmyra Atoll

Palmyra Atoll, owned and operated by the Nature Conservancy (NC), is considered one of the least disturbed coral atoll located in the Pacific Ocean. The NC paid $37 million to take control of this atoll. Never permanently inhabited, except during WW-II, the motus are visited by the occassional yacht crew. It was during onc such visit back in the 1970's that a couple was murdered and the murdering pirate is now in prison.

This mapping project was relatively fast and uncomplicated. The various layers of information were determined using Landsat ETM+ imagery. Consequently, the layers are "fairly well "determined. "Fairly well" is what you get working off of Landsat. "Fairly well" is what EVS (Enhanced Vector Shorelines) is. Compared to much of the mapping currently available on a global scale, "fairly well" is a major improvement.

Enjoy!

Labels: atoll, EVS, island, Landsat, Line Islands, map, Marplot, Pacific

Posted by Mr Minton at 2/17/2007 10:29:00 PM | Permalink | Comments | links to this post

Okino-tori Shima (20˚25'N., 136˚05'E.) is located about 375 miles SW of Minami-Io Shima. It was formerly known as Parece Vela or Douglas Reef. This coral reef extends about 2.8 miles in an E to W direction, is about 0.8 mile wide, and encloses a reef-encumbered lagoon. A number of small islets and above-water coral heads, 1 to 3m high, lie on the reef. Two small towers stand near the W extremity of the reef. It is a Japanese possession.

Caution.—A below-water reef, with estimated depths from 2 to 3m, has been reported to extend about 3 miles NW from the W part of Okino-tori Shima. Numerous tide rips were observed in the vicinity.

Breakers extend 0.5 mile off the E and W ends of Okino-tori Shima. It has been reported that breaking seas have been observed about 1 mile N of the W extremity of Okino-tori Shima, but were not observed in 1997.

Okino-tori Shima and the reported reefs should be given a wide berth, as there has been no recent survey. Boat passages have been reported on the SE and NE sides of the reef, but they have not been examined.

A large platform, about 20m high and supported by six rows of supporting pillars oriented approximately E and W, stands close E of the small towers. This platform, which appears abandoned, was reported (1997) visible on radar at a distance of 20 miles.

Another off-lying danger was reported in 1971. It appeared to be a coral-like shoal breaking in position 20˚18'N, 135˚28'E, bearing 259˚, 36 miles from Okino-tori Shima. In 1988, it was reported that a vessel transiting the area failed to see this danger. Vessels are urged to exercise caution when navigating within the vicinity. (SD Pub-158)

Wikipedia has an excellent article about this reef that claims to be an island. Why would Japan spend in excess of $600 million on this little reef? Because they needed it to have land above water. So they built up the three small reefs awash areas and transformed them into circular islands with strong rock reenforced shorelines. They basically fashioned three artificial islands to bolster their claim that this "island" allows them to claim an additional 200-NM EEZ around the island. As the Wikipedia article states the area has a potential for oil, among other resources.

Oh, the tangled web countries weave to bolster their claims for land. So goes the way of nations.

Enjoy!

Labels: atoll, Digital Globe, EVS, Google Earth, island, Japan, Pacific, reef

Posted by Mr Minton at 1/23/2007 06:15:00 AM | Permalink | Comments | links to this post

Little Makin Island KR

Visit Jane Resture's website that contains extensive discussions of Makin Island to include it's history during WWII. Another site that contains WWII information about the battle of Makin Island is the American Forces in Actions, the Battle for Makin Island. If this island is of interest you will find the data informative.

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This is the result of about 12-hours of digitizing, along with 2-NFL football games and numerous other interruptions. It was probably a 4-hour project without the distractions, but frankly that is life. We indulge our passions while encountering life's many demands. Was the 12-hours worth it? Sure! The map is well done and I am finished with this project.

Enjoy!

Labels: atoll, Digital Globe, Gilberts, Google Earth, island, Kiribati, Marplot, Pacific

Posted by Mr Minton at 1/08/2007 12:22:00 AM | Permalink | Comments | links to this post

Mankin Island - Marplot Map (1:4,000,000)

For the past 6-hours I have been digitizing various layers that makeup Mankin Island. I have been working off of a Google Earth / Digital Globe image so I have great resolution of ground features from which to work. So for 6-hours I am intently focused on this chunk of island floating in the Pacific. I took the 13-layers of digitized information from Google Earth, reformatted the files so they would drop into Marplot, my current mapping software and imported it. My map view at the time was at 1:4,000,000 scale. I looked for the imported files on the screen and couldn't find them. I could recognize many countries, islands and other geographic features, but not my project island. Then it hit me, "Damn, these islands I am working on are small!". They are tiny relative to the expanse of the ocean they reside in. They are drips and drops of land compared to large islands.

What's the point? Yeah, they are small, but to the people living on them they are HOME! They are the universe for a few hundred hardy souls that have lived on these isolated outposts of humanity from birth to death.

This is Mankin Island up close and personal. The image includes the airstrip and the taro gardens. Reefs ring the island. To the southwest of the airstrip is one of the villages that are located on these motus. I am in the process of mapping this little jewel. Before I am finished I will probably spend another 6-hours working. It is time well spent.

Enjoy!

Labels: atoll, Global Mapper, Google Earth, island, Marplot

Posted by Mr Minton at 1/05/2007 06:10:00 AM | Permalink | Comments | links to this post

Smithsonian Atoll Research Bulletin

Back in the old days when I used to scrounge island data in libraries, I loved to read articles from Smithsonian Atoll Research Bulletin (ARB). Now days, the series is available on-line through the generosity of the Smithsonian and the efforts of David Duffy, unit leader of the Pacific Cooperative Studies Unit at the University of Hawaii at Manoa. The articles are timeless and cover topics that are of interest to all island lovers. Take your time and explore the many bulletins. They are worth the research.

Enjoy!

Labels: ARB, atoll, island, PCSU, Smithsonian

Posted by Mr Minton at 1/01/2007 01:40:00 PM | Permalink | Comments | links to this post

Takaroa Atoll - GE Split Image Landsat (Right) and Digital Globe (Left)(1:37,000)

Earlier today I received a question from a viewer - "How do you locate hidden reefs using the color dodge effect? Is it the same effect used in Photoshop?"

Before I attempt to answer the questions let me walk you through a demonstration using a Flickr slideshow and some screen shots. The are relatively self-explanatory.

Finding Hidden Reefs Using The Color Dodge Effect

Now my non-professional opinion on why this effect does what it does with Landsat imagery. I believe the yellow that shows up on an otherwise nearly black-blue ocean surface is due to a shift in pixel value. The pixels that turn yellow are of a different value and that value is transformed into a yellow color using the color dodge effect in Global Mapper. I think the pixel value corresponds to the location of reefs in and very near to atolls and islands. I do not believe that they represent reefs farther away , but within the near proximity of the island, they seem to align with reefs.

I am certain that there is a professional opinion out there that will either explain the Landsat / Color Dodge interaction or not. It seems to work.

Takaroa Atoll with No Blend Effect

Takaroa Atoll with Color Dodge Effect

It sure looks like reefs to me!

Enjoy!

Labels: atoll, color dodge, Digital Globe, Global Mapper, Google Earth, island, reefs

Posted by Mr Minton at 12/29/2006 04:43:00 PM | Permalink | Comments | links to this post

I will post Sailing Directions information and any Internet information on this island later. I just wanted to get the project posted. The real breakthrough on this image and map is the ability to more accurately digitize and map the EVS Reef Deep layer.

The solid yellow in the above image is the hidden reef layer, which I have labeled as EVS Reef Deep. There is an even more subtle area that is defined by scattered yellow dots. This is most likely an even deeper reef layer.

Enjoy!

Labels: atoll, EVS, Indonesia, island, Landsat, map, Marplot, Pacific, reef

Posted by Mr Minton at 12/22/2006 07:35:00 AM | Permalink | Comments | links to this post

Located in the Taiwan Straits between mainland China and Taiwan is the group of islands called the Peng-hu Tao (aka The Fisherman Islands).

They are low lying islands peppered with coral reefs throughout. A couple of the southern islands are uplifted rocks. All of the others are merely meters above the water. Today they are destinations for tourists from all over the world. They offer the appeal of the Chinese culture and the escape of an island.

I had posted images and maps of these islands earlier, but I thought I would repost them all at a consistent scale (1:150,000). The maps are rendered in my EVS Shoreline style which shows mapping of traditional shorelines only.

Enjoy!

Labels: atoll, EVS, island, Landsat, map, Marplot, Pacific, Taiwan

Posted by Mr Minton at 12/22/2006 07:25:00 AM | Permalink | Comments | links to this post

The mystery island of the Marquesas. Now you see it! Now you don't!

In the early days of sailing this reef, with it's small motu, was often misplotted, mischarted and mistaken. With the advent of Landsat images and Shuttle photography the mystery island is now precisely located northeast of Eiao (30-km) and Hatutu Islands (15-km). It's reef outline is based on shuttle imagery. I believe that a few hardy sailors have explored this reef both on land, scant tho' it be, and under the sea along it's extensive reefs.

Enjoy!

Labels: atoll, EVS, Global Mapper, island, Landsat, map, Marplot, Marquesas, Pacific, Polynesia, Tuamotus

Posted by Mr Minton at 12/21/2006 01:50:00 PM | Permalink | Comments | links to this post

Tepoto Island (14˚03'S., 141˚25'W.) about 10 miles NW of Napuka, is about 18.3m high to the top of the trees; it is the NW island of the Iles du Desappointement. Landing is practicable, with assistance of the natives, on the W side of the island. (SD Pub-126)

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From Wikipedia: Tepoto, a coral island, is the northwesternmost of the Disappointment Islands, in the Tuamotu Archipelago, located at 14° 8' S lat and 141° 24' W long. The island is sometimes called Tepoto Nord in French, to avoid confusion with the Tepoto atolls 400 km (240 mi.)