EVS-Islands

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

Three Vector Shoreline's Compared - WVS, SWBD and EVS Precision

One of my readers suggested I evaluate SWBD shorelines in comparison to other freely available shorelines. Previously, I compared these shorelines with my own EVS precision shoreline. I'll do it once more.

The WVS is widely available and manageable in size. There is another popular version of it called the GSHHS. It repairs varous WVS anamolies. In addition, it conveniently breaks the dataset into land, lakes, ponds and islands. At only 56MBs zipped, it is a very attractive option. As one can see in the two images, the WVS is the least precise of all large scale global shorelines. It is designed to be used at scales of 1:250,000 and above. For most of us designing projects for our classroom, employers or customers, this dataset does a fine job, it is free and the size is reasonable. It is when we need to do large scale precise shorelines that we require the next best global shorelines

Although the SWBD is a quality product and provides the end-user with precise SRTM water-defined shorelines, it tracks the water. The SWBD attempts to identify the place where the water meets the shore. That should be the shoreline, but it isn't. The top image shows the SWBD shoreline tracking the reef edges and ignoring the numerous motus within the reef. For us island mappers, the SWBD is not precise enough to identify the many shoreline features we require.

The same can be said for the NGA PGS shorelines. They are extremely precise, using Landsat ETM+ imagery as their base imagery. This is the same imagery I use to construct my EVS precision maps. I have the NGA PGS shoreline loaded into Marplot, a mapping package I use. The dataset is divided into 24 separate groups. My global coverage, using this dataset, is outstanding - except where clouds or other atmospherics obscure the shoreline or the shoreline consists of water-inundated areas (marsh, swamp, mudflats), which the NGA PGS product didn't identify. The cloud obscured areas on Landsat ETM+ imagery are validly poorly mappable to unmappable. The water-inundated areas are mappable, but the NGA contract called for the exclusion of these shoreline features, thus they were not mapped. I beg to differ. This is shoreline that must be mapped. There are massive river deltas NGA PGS mapped that depict shorelines that look nothing like the original Landsat ETM+ image, which is full of features that the NGA PGS product did not map. They just happen to be water-inundated. They are features you and I would describe as shoreline. Make no mistake, when the shoreline is cloud-free and not water-inundated, which most Landsat imaged shorelines are, this global shoreline dataset is outstanding. It's just all of those river delta islands that they didn't map that I have a problem with.

Four Vector Shoreline's Compared

However, my EVS precision shorelines are pretty outstanding as well. When one compares my hand-drawn shorelines to programmed color tracking shorelines (or many other automated processes), my hand-drawn shorelines track quite precisely. Something about using one's brain processing powers, manual dexterity and years of experience that consistently allows one to create more precise shorelines than the WVS, SWBD and NGA PGS products.

As I work with Landsat ETM+ imagery and learn more about the digitizing craft, I am certain software is available that could do what I do more accurately, faster and in much less time. But it wouldn't be as much fun! Would it?

Enjoy!

Labels: EVS, GSHHS, Landsat ETM+, NGA PGS, SRTM, SWBD, WVS

Posted by Mr Minton at 12/31/2007 09:30:00 AM | Permalink | Comments | links to this post

Lake Tana - Landsat N-37-10_2000 (1:500,000)

Lake Tana - EVS Precision Marplot Map (1:500,000)

At times I like to open a Landsat ETM+ of a region of the world and explore. This time I traveled to Africa, specifically to Ethiopia. I know the country of Ethiopia is perched on highlands and Lake Tana is the primary source of the Blue Nile. I also have read the story of the Ark of the Covenant being spirited away from Israel first to upper Egypt at Elephantine Island, then to Tana Island and finally to St Mary of Zion Church in Axum. My curiosity about Tana Island got the best of me. My first task was to research to see if any maps of the island were available via the Internet. Nothing! Not even of the lake!

So my first task was to rectify the mapping of Lake Tana. The only mapping I have depicting this lake are at a scale of 1:1,000,000 (DCW). The shorelines are very coarse approximations of the Landsat imaged shorelines as depicted on N-37-10_2000. I have spent the last 6-hours mapping the shoreline of this lake. I worked at a scale of 1:31,250 for all mapped shorelines. Smaller islands in the lake were mapped at an even larger scale. The lake's shorelines were easy to discern and digitizing was uneventful, but tedious.

Nargadaga Deset - Landsat N-37-10_2000 (1:62,500)

Nargadaga Deset - EVS Precision Marplot Map (1-62,500)

This is the largest island within the lake and the largest island in Ethiopia. I carefully digitized it's shorelines, figuring the largest island had to be Tana Island. That is until I finished and began working in Marplot. It is there that I have my EVS Island name file (86,000+ named islands). It turns out bigger is just bigger. It is not Tana Island but Nargadaga Deset. Although it is a holy island, it wasn't the holy island I wanted.

After a little searching I found Tana Island located along the eastern shore of the lake. Not a large island, but at one time, the reputed resting place of the Ark of the Covenant.

Tana Island - Landsat N-37-10_2000 (1:31,250)

Tana Island - EVS Precision Marplot Map (1:31,250)

Here is Tana Island, all of 500-meters by 50-meters. It is a holy island, with a monastery located on it. No woment are allowed to visit the island. The priest living on the island will show any men visitors where the Ark was kept while on the island.

This was a fun mapping project. I got to map a number of islands at EVS precision. I went back to my mapping roots using Landsat ETM+ as my base imagery and didn't have to worry about offending any image owners and I mapped a major lake to boot! Now, that's living the high life.

Enjoy!

Labels: Ethiopia, EVS, Landsat ETM+, Marplot, Tana Island

Posted by Mr Minton at 12/17/2007 12:26:00 AM | Permalink | Comments | links to this post

Ancient Small Martian Island - Mars Odyssey THEMIS Image (19-meter)

Ancient Small Martian Island - EVS Map (19-meter)

What if the surface of Mars could be flooded to a depth of 20-meter? There would be islands where hills stand today. One of these islands would be this unnamed small island located in Ares Valles (16-lat - 30.4W lon). It would look like a barrier island, a 2-meter above water sand spit, shaped by tides and wind.

This is my first extraterrestrial island project. It took about 1-hour to complete. The circles scattered about are meteor plunks, most probably the large one's ejecta. The link to the Mars Odyssey website gives the curious reader loads of information about the area and the dry island features.

Perhaps if we pray for rain, Martian rain, and an increase in temperature, the seas will flow once again and this small island will live once more.

Enjoy!

Labels: EVS, Global Mapper, Mars Odyssey THEMIS, Martian Island

Posted by Mr Minton at 12/06/2007 06:22:00 AM | Permalink | Comments | links to this post

Isla Blanquilla - ISS015-E-7771 Image

A few days ago Earth Observatory carried this image of Isla Blanquilla and an interesting article about this small island located NE of Caracas Venezuela. Granted, if you are a US citizen, it is probably not your first choice to visit on a leisurely vacation due to the strained relations between our two countries, but the ISS image is pristine and details are mappable compared to the partially cloud-obscured Landsat ETM+ image. DigitalGlobe has never snapped a pic of this island either. So, I made do with the ISS image and created my map over a 4-hour period.

Isla Blanquilla - ISS015-E-7771 Georectified Image (1:62,500)

In order to use any non-georectified imagery, one must georectify it. I use Global Mapper to georectify. I loaded NGA PGS shorelines of this island (Region 14). These shorelines are very close to Landsat ETM+ shorelines. I selected 4 easily definable points on both my loaded shoreline line file and on my ISS image. It took about 10-minutes, with most of the time spent watching TV. Once the image was georectified, I began the task of digitizing the island shoreline, lower beach, upper beach, bare island, hi-low vegetation, airfield and the shallow reef surrounding the island.

Isla Blanquilla - EVS Marplot Map (1:62,500)

Once the digitizing was completed, I imported the completed layers into Marplot, where I still do much of my preliminary map construction. I am just used to working with it. I defined each layer and assigned it to pre-existing EVS layers. I did a quick layout of map titles, legend, scale and north arrow. Done!

At this point, I typically post. One day when I am given the opportunity and the time, I will "fancy" up my map using ImageForge prior to posting. Until that day arrives, this is as good as it gets.

Enjoy!

Labels: EVS, Global Mapper, ImageForge, ISS Image, Marplot, Venezuela

Posted by Mr Minton at 11/30/2007 06:54:00 AM | Permalink | Comments | links to this post

Rapa Iti - NE Coast GeoTIFF Image False Color (1:10,000)

I have been working on a redo of Rapa Iti Island, using an exquisite, cloud-free GeoTIFF image, for the past month, an "on-again, off-again" project. I have completed the island's revised shorelines taking them from EVS precision to EEVS precision. That is from Enhanced Vector Shorelines using Landsat ETM+ base imagery to Extremely Enhanced Vector Shorelines using 1-meter resolution base imagery. The "zooming" capabilities of EEVS are pretty amazing. If you map it, one could zoom in to view your backyard which is in need of mowing.

Anyway, the revised Rapa Iti shoreline is finished. I still have a variety of vegetation layers to digitize, along with human ground signatures (dwellings, roads, paths, harbor features, etc). Before I tackled these challenging layers I thought I would quickly generate topographic contours. Using Global Mapper's "Generate Contours" routine, one merely needs to import the appropriate SRTM image for your area of interest, select a few options and one has contours generated in seconds. These contours, when SRTM is accurate and complete (no voids), accurately reflect the elevations of your target area. But, SRTM tiles often have little voids, which can be quickly filled using software tools (my personal favorite is SRTMFill) and in certain areas, big voids, which are difficult to reliably fill. After much thought, research and counting my money (I hate to spend money on pricey software), I decided to use a tried-and-true method "eye-ball-it". Any cartographer worth their salt cringes at this method. Too often, unscrupulous map-makers foist their finished product off as a rigorously crafted map following standard cartograph protocols, when, in fact, the map is more fiction than fact - none of which speaks kindly of the "eye-balling" method. However, since I do not have the means to obtain surveyed contour lines or modified SRTM data of my target island, I'll just "eye-ball" this portion of the project. This involves looking at the underlying land features and comparing them to accurate, reliable contours, guess-timating possible alignment of the various misaligned contour tracks (i.e., 20-meters, 40-meters, etc) and finally realigning them.

Rapa Iti - NE Coast Misaligned Contours Realigned (1:10,000)

Let's begin with Maputu Pt or the NE Coast of Rapa. Because the SRTM data was incomplete, containing a large void (no data or incomplete data), this point had contours that were spilling into the ocean.

Rapa Iti - NE Coast SRTM Base Image Misaligned Contours Realigned (1:10,000)

The above image shows the SRTM limits as a darker shade of green, when, in fact, the actual shoreline is west of the SRTM shoreline. Using the GeoTIFF image, I was able to realign the misaligned contours (see the blue contours). The method I used is "eye-balling". I looked at the shape of the easterm side of the point and beginning with the highest elevation, I realigned each contour level. The eastern side of Maputu Point appears to be quite steep, based on the GeoTIFF image and my contour realignments.

Rapa Iti - NE Coast EEVS Map with Realigned Contours Draped over SRTM Image using GM's 3D Effect (1:10,000)

Using Global Mapper's 3D Effect, I was able to see my work in a different, more revealing way. I think my "eye-balling" of the misaligned contours works quite well.

Rapa Iti - NE Coast GeoTIFF Image False Color (1:10,000)

From my GeoTIFF image to . . .

Rapa Iti - NE Coast EEVS Map Misaligned Contours Realigned (1:10,000)

Rapa Island, Maputu Point using EEVS precision (hi-res imagery). The green contours are generated from SRTM data. The blue contours are my realigned contours. They track the elevations more accurately then the SRTM based contours.

Rapa Iti - S Coast GeoTIFF Image False Color (1:10,000)

Rapa Iti - S Coast Misaligned Contours (1:10,000)

Along with the misaligned contours in the NE, another area of misaligned contours is along the southern shore. Looking at the GeoTIFF image without contours, one sees a coastline fronted by some pretty steep south facing slopes. Looking at the contours generated from the SRTM data, it is very easy to locate the problem contours. The steep slope is either poorly defined or nondefined by contours. Based on SRTM data, it appears the immediate shoreline is a very steep cliff fronting the shore. The contours do nothing toward resolving the remainder of the slope. Also the point that extends out is not defined.

Rapa Iti - S Coast EEVS Map Misaligned Contours Draped over SRTM Image with 3D Effect (1:10,000)

Looking at the contours draped over the SRTM image the reason for the misalignment is obvious. Where there should be elevation data there is none.

So I will carefully "eye-ball" the slope and assigned contours where I guess-timate they belong. You know and I know these realigned contours are nothing more than educated guesses. In the case of this map of Rapa and in consideration of the quality of the base GeoTIFF imagery, the educated guesses will ultimately lead to a good map that is useful to gather an understanding of the topography of this island. If I were to have actual contours that could be applied to this map, I could produce a high quality product useful for a wide variety of purposes. As it is, my map containing "eye-balled" contours will be a quality product useful for a variety of purposes.

Stay tuned. This project should be finished within the next few weeks. Then, you be the judge.

Enjoy!

Labels: contours, EEVS, EVS, French Polynesia, GeoTIFF, Global Mapper, map, misaligned, Rapa Iti

Posted by Mr Minton at 10/16/2007 08:35:00 AM | Permalink | Comments | links to this post

Jabal al-Tayr Island Location from Google Earth

Jabal al-Tayr - Landsat Image N-37-15_2000 (1:25,000)

Jabal al-Tayr - EVS Map (1:25,000)

In the southern portion of the Red Sea at 15.54N 41.83E is this small island. If you didn't know where it's located and you are using Landsat to find it, it's very difficult to see. Using some image modifying features found in Global Mapper v9.0 the island shows up. It looks like there are clouds swirling off of the southeastern portion of the island. These clouds appear to be very dark and dusty, like volcanic ash. Well it turns out that this little round island is actually a very active volcano. According to a post in Google Earth Blog this little island's recent eruption led to the death of 8 Yemeni citizens. The post includes a KMZ file that includes the above posted Landsat image.

My EVS precision map of Jabal al-Tayr accents the island's simple shoreline. In addition, it includes 20-meter elevation contours. I used Global Mapper's contour generation routine. One needs to import the appropriate SRTM, then generate your contours.

Jabal al-Tayr - DigitalGlobe Image (Non-obscured)

DigitalGlobe has a non-obscured image of the island, for a price ($400+) for those of you wanting to do additional research on this island.

The Red Sea is one of the world's critical ship transit channels and smack dab in the middle is this active volcano. If that doesn't beat all!

Enjoy!

Labels: DigitalGlobe, EVS, Global Mapper, Landsat, Red Sea, volcano, Yemen

Posted by Mr Minton at 10/01/2007 09:55:00 PM | Permalink | Comments | links to this post

Pulau Reong - Google Earth Locator

Pulau Reong - DigitalGlobe Image from Google Earth (1:12,500)

Pulau Reong - EEVS Map (1:12,500)

This island map has taken about 2-hours from start to finish. The most difficult aspect of digitizing it was how to handle the western portion of the island. I elected to use Landsat N-51-05_2000 imagery to complete vectors for the western portion of the island. The majority of the work was done in Google Earth using DigitalGlobe (DG) hi-res imagery.

This island interests me for what it doesn't have. As I studied the DG imagery I cannot find any human signs - no village, no house, no plantation, no large areas of bare earth. It seems that this island's primitive vegetation layer, which is heavily forested, is intact.

I would love to explore this island. Could you image moving through the forest and encountering the flora and fauna within this pristine environment. White sand beaches are found along much of the shoreline. Although the island gets heavy rainfall, there are no visible swamps or mosquito-laden wetlands.

Now back to reality, The island is probably full of bugs, small and large critters. It probably has reptiles named Deadly Five-Pacer. You know, five paces and you're a gonner. Any time you see a tropical forest, the area is innundated with rain and subject to blistering high humidity.

How negative! The explorer in me would love to visit this island. The practical city-dweller, he would still like to visit, but with mosquito nets, raincoats and snake bite kits.

Enjoy!

Labels: DigitalGlobe, EVS, Google Earth, Indonesia, Landsat

Posted by Mr Minton at 9/22/2007 04:16:00 PM | Permalink | Comments | links to this post

Balesin Island RP

Balesin Island - Landsat Image N-51-10_2000 (1:31,250)

Balesin Island - EVS Marplot Map (1:31,250)

I don't purposely work on islands that have "claim's to fame", but all of the ones I have worked on seem to have interesting stories to tell. Balesin Island is no exception. Seems this small island is the location of a high-class resort. You and 40 of your friends can enjoy the miles of sandy beaches. Just pony up $85 per room per night and transportation to the island. Your accomodations are top rate. The service is exquisite. Everything is first class.

I was going to say something silly, but I won't. I have never been to the island, but one of the websites that sells the islands attributes makes it look great. Now, alittle about why I mapped it.

One of my students wants to become a cartographer. During my lunch time, I showed her how I go about making an island map. Since I had this Landsat image loaded on my computer at school, I slected a small island, Balesin Island. I showed her how to digitize a shoreline and the various layers of additional information that I would map to complete this project. I estimated that this project would require an additional 4-hours of work. It has taken about 6-hours to complete. Tomorrow, I'll share this completed project with my aspiring cartographer. Hopefully, she will remain inspired.

Enjoy!

Labels: EVS, Landsat, map, Marplot, Pacific, Philippines

Posted by Mr Minton at 9/19/2007 09:30:00 PM | Permalink | Comments | links to this post

Ostrov Tyuleniy - Google Map Locator

Ostrov Tyuleniy - Landsat Image N-38-40_2000 (1:50,000)

Ostrov Tyuleniy - EVS Map (1:50,000)

This Caspian Sea island is off of the coast of Dagestan. I have been digitizing this island for the past week. It was a fairly complex project due to the marshland that makes up much of the island. My research uncovered reports on Tyuleniy birds, insects, fish and crude oil exploration. The crude oil exploration was conducted back in 2005 by the German company Wintershall. Turns out they are one of the big players in the world of oil. They are working with Russian groups to explore this potentially oil rich region in the Caspian. My look into Wintershall's website did not uncover any additional information.

I like my map. It looks good and is as accurate as Landsat imagery allows.

Enjoy!

Labels: Caspian Sea, EVS, Google, Landsat, map, Marplot, Russia, Wintershall

Posted by Mr Minton at 9/17/2007 11:42:00 PM | Permalink | Comments | links to this post

Groupe Acteon - Landsat Image S-08-20_2000 (1:200,000)

Groupe Acteon - EVS Map (1:200,000)

Ignorance is bliss. or so they say.

Two years ago I was thrilled to make a map using Landsat ETM+ as my base imagery. These Enhanced Vector Shoreline (EVS) maps are some of the most detailed, consistently formatted and visually appealing maps freely available to any and all. I have mapped islands, employing rigorous and proven procedures, ensuring that the stage, which consists of Landsat images and EVS maps, is clearly rendered so that their individual stories can be told in their unique geographical context, as evidenced by the Groupe Acteon Landsat image and EVS map above.

Groupe Acteon - DigitalGlobe Image in Google Earth (1:200,000)

Ignornace is bliss. until you know what you know.

What used to be, in Google Earth (GE), a smudge of green suggesting land, is now DigitalGlobe's (DG) high resolution imagery. GE and DG, working together, gives us exquisite high resolution views of islands throughout the world, including Groupe Acteon. Where Landsat ETM+ used to rule, not so anymore. The new ruler is DG using GE's mapping platform. DG's high resolution imagery costs big bucks, unless you are a mega-funded government agency. Big bucks that us little folks will never be able to afford. Working with GE, this imagery is now ours to view. Oh, yes, and ours to use as base imagery to create non-commerical maps (just make sure you credit sources).

Last night, I finally faced up to a harsh reality - EVS quality pales in comparison to Extremely Enhanced Vector Shorelines (EEVS) quality which comes from DG's high resolution imagery. The improvement in shoreline resolution is dramatic. What Landsat suggests, DG clearly shows. Striving to produce the best map, I am faced with a genuine dilemma, to redo EVS quality maps when EEVS quality is available, or not. I want to say "Not.", but I realize "Redo" is, most often, the correct response. Let me explain. The islands I map are very small chunks of real estate. Consequently, little digitizing inaccuracies become very big mapping inaccuracies. Take a look at the following.

Matureivavo Atoll - Landsat Image S-08-20_2000 (1:20,000)

Matureivavo Atoll - EVS Map (1:20,000)

Digitizing from the Landsat image, I was able to create the above EVS map of Matureivavo Atoll. Considering what Landsat was able to show, in my opinion, the resulting map was a solid effort. However, Landsat, at 14.5 meters per pixel is not DG HiRes at 1 meter per pixel.

Matureivavo Atoll - DigitalGlobe Image from Google Earth (1:20,000)

The EEVS map I will create, using the above DG imagery, will be considerably different than my Landsat effort, as it should be. I will map the majority of this complex reef as being water inundated. The small sand bars will be mapped as above water features. The sparse vegetation layer along this reef will be designated as underwater vegetation and be mapped accordingly. The resulting shoreline of this section of reef will be considerably different. Much of the original EVS quality shoreline will now be mapped as an underwater feature. I will make many different mapping decisions based on this high quality image, resulting in an EEVS quality map.

The horns of my dilemma - Is there room for both EVS and EEVS quality mapping?

Obviously, when Landsat imagery is the only available imagery, EVS rules. However, when DG imagery is available for the same area, EEVS rules. As I compare my EVS maps to DG's EEVS quality imagery and I find the EVS details are of sufficient quality to qualify as an accurate map, it will remain. If I compare an EVS map to DG's EEVS quality imagery and find it lacking in detail and accuracy, I will redo it.

Enjoy!

Labels: DigitalGlobe, EEVS, EVS, Google Earth, Landsat ETM+

Posted by Mr Minton at 8/03/2007 06:52:00 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

Dao Bach Long Vi - Landsat Image N-48-20_2000 (1-17,500)

Dao Bach Long Vi - Marplot Map (1-17,500)

I haven't posted one of these in a long time. It is an Enhanced Vector Shoreline of a Vietnamese island. It seems that I posted this before, but I'll be darned if I can find it on my site. Oh, well.

Dao Bach Long Vi is a potential Marine Protected Area. For now, it is home to a lighthouse and a very small population of fishermen.

Dao Bach Long Vi - Marplot Map (1:17,500) - A Fancy Map

Yes siree, this is a fancy map. I took my original map, less lat/lon and scale box, and worked it over in my free paint program, ImageForge. I am still experimenting with fonts and text (credits and such), but the overall composition looks good. It took an extra two-hours to complete this project, but it is well worth it.

View Dao Bach Long Vi on Google Maps

Enjoy!

Labels: EVS, ImageForge, Landsat, map, Marplot, South China Sea, Vietnam

Posted by Mr Minton at 7/09/2007 11:42:00 AM | 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

World Vector Shorelines (WVS) is the default shoreline for most government produced maps. It is also used extensively by many in the commercial mapping arena to produce their products. It is an excellent vector map file that shows shorelines of the world in exquisite detail.

That said, I searched for a detailed map of the Tokelau Islands at a large enough scale that all three of the atolls (Atafu, Nukunonu and Fakaofo) could be displayed.

Google Image Search Results - Tokelau Map

Every readily available map used the same data source for their shorelines - WVS. The best scale to display all three atolls is 1:750,000. I thought that WVS would be the ideal source - Wrong! Knowing what I know about atoll shapes and the importance of including the reef as part of the shoreline, WVS was woefully inadequate.

The answer was simple - merely create a new vector file of these three atolls. Using Global Mapper and Landsat ETM+ as base imagery, I worked at a scale of 1:62,750 and digitized the land areas and reefs of these three atolls. Using Marplot I created this new layer of mapping information called Enhanced Vector Shoreline-Rough (EVS-R).

EVS-R and WVS (1-1,000,000)

EVS-R and WVS (1-250,000)

Not only is the EVS-R a more detailed image, but it is accurately plotted at this scale. You will notice that the WVS is misplotted further north than it should be.

It is a major improvement over WVS. What do you think?

Enjoy!

Labels: EVS, EVS-R, Global Mapper, Landsat, Marplot, WVS

Posted by Mr Minton at 7/02/2007 01:33:00 PM | Permalink | Comments | links to this post

Verde Island - Landsat N-51-10_2000 Image (1:31,250)

Verde Island - Marplot Map (1:31,250)

Verde Island is located between the islands of Mindoro and Luzon in the Philippines. It is a project of opportunity, a random island in a country of thousands of islands. So what is the story. It seems this passage between the two large islands is an important west-east route. It seems that a Spanish galleon had problems off of Verde Island, sunk in about 60-m. Divers today still find booty that is dated to the time of this ship's sinking. Most divers swim around a look at the reef and it's myriad of lifeforms. This island is 7-km by 5-km and has a number of small villages scattered about.

I'm making my map labels pretty. The Marplot generated labels were functional, but plain. I like the look of these custom labels. As I stated previously, they are one size only. It would be nice to have the shrink and expand based on the map scale. I like my text fox and entry. The contours were generated from SRTM 61-10 using Global Mapper's contour generation function.

Enjoy!

Labels: disitize, EVS, Global Mapper, island, Landsat, Marplot, SRTM

Posted by Mr Minton at 6/19/2007 12:34:00 AM | Permalink | Comments | links to this post

Digitizing from Landsat N-30-60_2000 ETM+ at 1:12,500

As my frequenct readers are aware, the 1:12,500 scale is what I typically use when I digitize EVS quality shorelines from Landsat ETM+ mosaics. I am able to distinguish features without having the image become a montage of different colored pixels. If I have a poor quality image, I might work at 1:25,000 to 1:50,000. A great image allows me to work at 1:6,750 occassionally. But typically, my work is done at the 1:12,500 scale.

I loaded this Landsat image into Global Mapper, zoomed in on an island shoreline, and began work. After three hours of digitizing, I decided to zoom out and look at the entire island group, which I assumed was the Faroes. They really looked strange!

Funny Looking Faroes?

I checked out my WVS map files and these Faroes were in the wrong place. They were right where the Shetlands should be. I checked out Wikipedia and located a MODIS image of the North Sea and there, just above the Orkneys, are the Shetlands and to the northwest of the Shetlands are the Faroes. They kind of look alike, but not really.

Orkneys, Shetlands and Faroes

Shetlands (left) and Faroes (right)

So, it looks like I am digitizing Shetland shorelines and not the Faroes. It seems that Landsat has dropped the ball on the Faroes. I am certain that they have imaged it numerous times, but none of these images are freely available to the public.

I'll be content to map the Shetlands for now and tackle the Faroes another day.

Enjoy!

Labels: EVS, Global Mapper, Landsat, MODIS, Orkneys, Shetlands, UK

Posted by Mr Minton at 6/14/2007 11:53:00 AM | Permalink | Comments | links to this post

North Ronaldsay Study

Let's begin this post by giving credit, where credit is due. My first attempt at shorelines for North Ronaldsay were extracted from imagery taken from MS Live Local. It appeared to be cloud-free Landsat imagery, but I'm not certain. The first attempt to map this island's shoreline resulted in very rough lines. These shorelines were "okay".

Intrepid searcher that I am, I began to scour the Internet for mapping of North Ronaldsay. The usual cast of characters showed up, but nothing great. That is until I discovered Get-A-Map, which uses Ordinance Survey raster map images. I believe the original maps were at 1:50,000 scale. I found another treasure trove of maps, text and