Marmara Island TR - Modifying SRTM v4 TIF with EVS Precision Coastal Vector File

Turkey - SRTM with EVS Vector Modifications

The map of Turkey on the left is a portion of a 600-MB World Map created by Tom Patterson. His excellent and informative website, Shaded Relief, contains a wide variety of shaded relief maps. He explains how you could create your own shaded relief maps. I have been content to download his finished maps and use them in my classroom. The students love working with them.

I have been a long time user of SRTM data. Using tools within Global Mapper, I was able to generate interesting 3D views of islands. Last week I came across SRTM v4 data at CGIAR Consortium for Spatial Information (CGIAR-CSI), which I call Cigar (See-gar) for short. I downloaded a number of SRTM TIF images covering Turkey, where I am plotting Roman era towns and cities. Using the Shaded Relief Natural Earth 1 world map I was able to plot at scales of 1:1500000 to 1:1000000. When I attempted to work closer the map became a screen full of pixels. What to do?

Marmara Island - SRTM EVS Modifications Before and After (1:25,000)

The SRTM v4 data offered me some intriguing possibilities. First, I was able to zoom into areas at scales between 1:500,000 down to 1:50,000. At 1:50,000 I had to contend with pixels. The vertical side of a pixel in the part of the world I am working in is 90 meters, the horizontal side is 70 meters. Clunky looking when working at 1:50,000. It was then that I had my "ah-ha" moment. I loaded Landsat imagery on top of the SRTM imagery. I then digitized shorelines using the Landsat imagery (section 1). I switched off the Landsat imagery and my EVS precision shoreline cut through SRTM v4 pixels (section 2) and allowed me to determine the shoreline on the SRTM image. The SRTM modified shoreline is now useful to scales as fine as 1:25,000 (section 4).

I know! A 14.5 meter pixel defining a 90-meter pixels leads to potential problems. However, for my purposes, plotting Roman era towns and cities, these SRTMs modified with EVS precision shorelines work just fine.

Marmara Island Vicinity - SRTM with EVS Modifications Before and After (1-250,000)

And at 1:250,000, they look great!

A word about my custom hypsometric tints. The colors I initially took from the Shaded Relief website. But I have since tweaked them a number of times. The current version, certainly not my last, looks great for this part of the world.

I am slowly, but surely working my way around the shoreline of the Sea of Marmara, a place I spent time as a young man. I do hope this was both informative and interesting.

Enjoy!

How To Digitize Vegetation and Land Layers using Landsat Imagery at 1:12,500 Scale

Faaite Atoll FP - Comparison - Landsat Image, EVS Precision Map, DigitalGlobe Image (1:12,500)

I keep telling all of you that I typically digitize off of Landsat imagery at approximately 1:12,500 scale. Checking out the above montage you will see a Landsat image of a portion of Faaite Atoll FP. Beneath it are two layers of information I digitized using Landsat as base imagery, vegetation and land. The final DigitalGlobe image from Google Earth is of the same stretch of atoll. The Landsat image has a green hue over all of the land and vegetation features. However, having digitized so many islands the sand or low vegetation, which I classify as land is identifiable. My Landsat derived vegetation layer is a decent approximation based on the vegetation shown on both Landsat and DigitalGlobe's hires imagery. The digitized land layer, I believe, is a strong match.

Why should one care at what scale one is able to digitize using Landsat as base imagery? Ask any photogrammetrist and they will tell you Landsat is reliable between 1:125,000 to 1:62,500. Each pixel covers a ground area of 14.5 meters by 14.5 meters. However, working at 1:12,500 does not render an image useless, but allows one to discern details in a rough but usable fashion. I can't make out individual trees, but I can identify stands of vegetation and most often the density of that vegetation. The most difficult feature on an atoll to reliably digitize is that portion of the reef which is awash depending on the time of day (high tide or low tide) and the amount of vegetation found growing on the reef. It is often difficult to determine whether the feature is above water land or below water shallow reef. Typically, if I'm uncertain I classify the feature as above water land.

Who knows, one day you might want to try your hand at island map making and you will want advise as to what scale you might expect to work at using Landsat as your base imagery. Digitizing at 1:12,500 should work just fine. Give it a try.

Ailuk Atoll RMI - 49 Named Motus Out of 57

Ailuk Atoll - Locator Map from ARB-127

Ailuk Atoll - Map From ARB-127

Just a few more atolls to map to complete the Republic of Marshall Island (RMI), specifically the Radak Chain. This particular island is made up of 49 named motus out of 57 total. I labeled a few of the larger motus. The atoll is home to 488 people. They make their living from harvesting and the sale of copra, fishing andcatering to the few tourists that come their way.

Ailuk Atoll - Landsat Image N-59-10_2000 (1:165,000)

Ailuk Atoll - DigitalGlobe Image from Google Earth (1:165,000)

I began this mapping project using the Landsat image. The clouds obscure many of the motus and underlying reefs. I checked out Google Earth's imagery and found the above DigitalGlobe image. First I constructed an image mosaic from the DG data, georeferenced it using my Landsat image. Once finished, I digitized the following layers of information: Island Polygon, Vegetation, Reef Awash, Reef Break, Reef Shallow and finally Reef Deep. Due to the size of this atoll and to display the entire atoll on one page required a scale of 1:165,000.

Ailuk Atoll - EVS Precision Map (1-165,000)

And here is the finished map. I only labeled the larger motus. The map took about 10 hours to complete. The motus were mapped primarily using DG images from Google Earth except in the southern part of the atoll where no DG imagery is posted. Whereas the reefs were mapped primarily from Landsat N-59-10_2000 imagery.

I finished the map at 12:00 AM this morning. At the time, the map and the post looked pretty good. This morning I had to make a number of corrections to both the post and the map. A word of advice, don't map after midnight. Your judgement gets cloudy and can obscure your normally keen perception.

Enjoy!

Thoughts - More Marplot's Can and Can't Do's

Marplot Mapping Software

Marplot Mapping - Census Tiger Data for Prince William County VA

Mr MInton's World Shoreline Marplot Map

This post is a discussion of some of the things that one can do with Marplot, and they are many. This is not a discussion of how seamlessly Marplot works with the Census TIGER files. It is a discussion of Marplot's ability to hold a large number of vector and raster layers of information within a user defined map. My map is called World Shoreline and it currently contains 200-plus unique layers of information. Marplot allows me to switch layers on and off as I need them. I control the layer's range, color, line width, fill, and symbol. I can override my choices at any time and modify layer appearance. Marplot let's me take polylines and create polygons. In addition, it easily allows for the creation of islands of information within larger islands. Oh, by the way, it's free.

Marplot can import BMP, PNG, JPG and a few other raster image formats. However, direct import file options are limited to DAT file format (ARC Ungenerate), TXT file and MIE format (Marplot's own format). One can import SHP files using a freely available piece of conversion software called shp2mie. Marplot's digitizing features are functional, but limited.

I began using Marplot over 5-years ago. It was free and seemed to offer some useful possibilities. As I gained more and more experience working with it, I've come to appreciate the breadth of options available in it. It is a "poor man's" GIS package. I am aware of extremely robust Open-Source GIS packages. I have tried them and for my work they are too complex. Marplot is the ticket for me.

However, if I had to depend solely on Marplot as my digitizing software, I am quick to acknowledge that the quantity of my EVS Island maps would be a fraction of what I am able to currently produce due to the serious limitations of Marplot as a digitizing platform. My digitizing and raster image manipulating software of choice is Global Mapper. Global Mapper allows me to load a number of Landsat ETM+ images quickly and easily. Within seconds, I am digitizing shorelines. It has many additional features and is used by GIS professionals to accomplish quite demanding and complex mapping tasks.

I have tried other mapping packages, but I keep coming back to Marplot. Oh, well, as they say, "dance with the one who brought you." and Marplot maps are an integral part of every one of my EVS-Islands projects.

Enjoy!

Nukutavake Island FP - Third Time Posting is the Charm

Nukutavake Island - Landsat Image S-07-15_2000 (1:25,000)

Nukutavake Island - Marplot Map (1:25,000)

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!

Jabal al-Tayr YM - One More Time

Jabal al Tayr - ASTER Image

This image is the latest post on one of my favorite websites - EO Newsroom. This site is always good for informative and interesting images, typically accompanied by well-written articles. If you've never visited, visit - it is worth the time.

I am including this ASTER image of Jabal al-Tayr. It is a closeup of the volcano that erupted September 30th. The image used in my previous post, Jabal al-Tayr YM, was extracted from a circa 2000 Landsat mosaic. This one, at 15-meter resolution, is clearer than Landsat. Fortunately, my original map is still a high quality rendering of the island shoreline and it's contours.

Enjoy!

Comparison - Vectors to Raster or Mr Minton on the Scene

Zooming in Using Vectors

This post is aimed to all readers that are content to look at a picture (image) of a map and never enjoy the thrill of a good vector zoom. When I first began using maps, I was a picture user. Never having been exposed to vectors and their inate characteristic of zooming to amazing levels of detail. I know that the levels of detail are only as good as the original map maker can construct them, but given the right map maker one can discover amazing features tucked away within a vector map. Such as my map of Jabal al-Tayr. Who would have imaged that Mr Minton, yours truly, had his avatar perched on the northwestern plateau of Jabal al-Tayr. I'm sure he is safe, even after the volcanic eruption of a few days ago. He is writing this post after all.

Seriously, the ability to add levels of detail to maps is outstanding in today's world of readily available hi-res digital imagery compliments of Landsat, Google Earth and DigitalGlobe.

Comparison of a Raster to Vector - Jabal al-Tayr at 1-cm : 1,562-m

So, all of you raster rookies, explore the exciting world of vectors. Once you've been there, you'll never want to go back to static rasters.

Enjoy!

Jabal al-Tayr YM - Red Sea Volcano

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!

Pulau Reong ID - A Primitive Tropical Forest

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!

Balesin Island RP

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!

Ostrov Tyuleniy RS

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!

Thoughts - Sherbro Island SL and a Mystery Landform

Sierra Leone and Sherbro Island

Sherbro Island - Landsat N-28-05_2000 (1:275,000)

Sherbro Island is located in the center of the first image. As can be seen in the next image, it is a fairly large river-mouth island, which typically results in large portions of the island being water-saturated with highly dynamic shorelines. That is the case for much of this island. However there are other parts of the island that are of a more permanent nature. For example, the southwestern ocean-edge of the island is uplifted and less subject to the whims of the weather and river dynamics.

Sherbro Island - EVS Marplot Map (1:275,000)

This project has resulted in long hours of water-feature digitizing. Because the vectors were created using Landsat imagery, the digitizing task was simplified. However it has been a chore getting the project to this point. I still have a number of landforms to digitize (swamps, mudflats, sandbars, etc.).

Sherbro Island - What is this landform?

I think this landform is a series of old shorelines. The zoomed images show trails crisscrossing them leading to a from the ocean shore. When I first saw this feature, I thought it might be areas of cultivation. After studying the DigitalGlobe image from Google Earth of this landform, it doesn't appear to be cultivated areas.

My question to EVS Islands readers, "What is this landform?". Thanks in advance.

View Sherbro Island on Google Maps

Enjoy!

Thoughts - Easter Island Shoreline 12,615 Vectors Later

Easter Island - EEVS Map (1:100,000)

This is a continuation of my previous post. EEVS quality mapping requires lots of vectors. As the title states, at this preliminary stage, 12,615 vectors were digitized by me to create this shoreline. I worked in Google Earth using the path tool. The first pass was relatively fast taking about 6-hours. The final pass, the fine tune, took another 3-hours. I will have to work on this shoreline in Global Mapper to finish it. Two parts of the island, the north and western edges will be digitized using Landsat as they are not included in the Google Earth map. I have loads of work to do on this map digitizing layers of information.

My point is that DG imagery is great, but to execute a quality shoreline, one must do lots of digitizing.

Enjoy!

Nikumaroro Atoll KR - Exquisite Map or What I've Learned in a Year.

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!

Comparison - MrSID with JPG, TIFF 8-bit and TIFF 24-bit

Some time ago, I did a comparison of images taken from a Landsat ETM+ mosaic - JPG, TIFF and MrSID. I thought I knew what I was doing, but I didn't. Finally, after many months, I intend to right my wrong.

This comparison looks at images taken from a Landsat ETM+ mosaic (N-32-65_2000). It looks a whole lot better if you select the image and follow it to my Flickr EVS-Islands area. Look at these images full size (1280x1024). After studying them for a few minutes, you will be able to discern differences in colors and clarity of details. The master image is the Landsat ETM+ (N-32-65_2000) in MrSID format. The images derived from the master image are in JPG, TIFF 8-bit and TIFF 24-bit. TIFF images tend to be larger (MBs to KBs), sometimes much larger (GBs to MBs) than JPG images. All second sets of images use an effect found in Global Mapper called Anti-Alias. It smooths the pixels, using an industry standard algorithm. I prefer to map with this effect on, as it gives a smoother shoreline to follow when I digitize. On with the visual comparison.

MrSID and JPG

Tranoy Area NO - Landsat N-32-65_2000 (1-10,000) MrSID (L) JPG (R) without Anti-Alias

Tranoy Area NO - Landsat N-32-65_2000 (1-10,000) MrSID (L) JPG (R) with Anti-Alias

(Again - look at the full-sized images in Flickr EVS-Islands - select the image, in Flickr, select "All Sizes" and you will be viewing the image at it's original size of 1280x1024.)

JPG has noticeable loss of detail. When I look at the image without Anti-Alias, it appears fewer colors are used in the image creating the illusion of larger pixels. I use JPG when I post images, because the files are many times smaller in size (KBs vs MBs) and the clarity is sufficient for viewing.

MrSID and TIFF 8-bit

Tranoy Area NO - Landsat N-32-65_2000 (1-10,000) MrSID (L) TIFF 8-bit (R) without Anti-Alias

Tranoy Area NO - Landsat N-32-65_2000 (1-10,000) MrSID (L) TIFF 8-bit (R) with Anti-Alias

TIFF 8-bit is an improvement over JPG, but larger in size. The TIFF format is typically much larger in size. MrSID came about because of gigabyte sized TIFF images. MrSID format could shrink the TIFF images into something more manageable and viewable. That said, TIFF 8-bit gives a wider range of colors, doing a better job with subtle shading. The image is clear and almost as good as the original MrSID image. It is a good duplication of the MrSID base image.

MrSID and TIFF 24-bit

Tranoy Area NO - Landsat N-32-65_2000 (1-10,000) MrSID (L) TIFF 24-bit (R) without Anti-Alias

Tranoy Area NO - Landsat N-32-65_2000 (1-10,000) MrSID (L) TIFF 24-bit (R) with Anti-Alias

TIFF 24-bit is as good as it gets compared to the other two options (JPG and TIFF 8-bit). When viewing the original size image, it is difficult to distinguish between the MrSID image and the TIFF 24-bit image. The colors most nearly duplicate those found in the MrSID image. Clarity and sharpness of detail are a near mirror of the MrSID image. It is a solid reproduction of the MrSID master image.

If the size of the image doesn't matter, but the clarity of details is important, the TIFF options are far superior than JPG. However, if size of the image is of concern and the sharpness and clarity of details is not, go for the JPG.

Okay, I know that all of you image specialist are guffawing at my layman's descriptions. However, most of my viewers are laymen, and a few laywomen. They appreciate the non-technical descriptions.

Enjoy!

How To Conduct Your Own Photographic Intelligence (PHOTINT)

According to the Dept of Defense photographic intelligence consists of collecting products of photographic interpretation, classified and evaluated for intelligence use. Also called PHOTINT.

Curious soul that I am, I thought I would give it a try. My analysis is non-classified, but interesting.

Development in Ya Long Bay and at Ya Long Naval Base (2002-2007)

Lang-yeh Wan (Ya Long Bay) contains several islands and islets. Dongmao Zhou (18°11'N., 109°41'E.), 111m high, is the outermost island of the bay. A 14m high rock and an 11m high rock lie close E and N, respectively of the island. Hsi Chou, 105m high, lies 1 mile W of Dongmao Zhou and is marked on its SE end by a light.

Yeh-Chu Tao, an island, 95m high, stands within the bay about 2.5 miles NW of Dongmao Zhou. Two small islets, Tung-p'a and Hsi-p'ai lie to the W of Yeh-chu Tao. Anchorage can be taken in 12.8 to 14.6m, mud and sand, about 0.8 mile NE of the E end of Yeh-chu Tao. However, the NE wind blows strongly between the hills of the peninsula to the E and during S and SE winds, considerable swell may build up in the bay.

Between Pai-hu Chiao and Jinmu Jiao (Chin-mu Chiao) (18°10'N., 109°33'E.), 2.8 miles WSW, the coast is bold and steep-to. This headland marks, at Jinmu Jiao, both the S point of Hainan Dao and for descriptive purposes, the dividing line between the E and W coasts of the island. The peninsula rises to 380m to the NE of the signal station above Jinmu Jiao. A light is shown from the S extremity of this point and the coast to the W is steep-to and bold; a racon is situated at the light. (SD Pub-161; pg 66)

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The imagery used in this exercise comes from DigitalGlobe (DG) catalog images found in Google Earth (GE). I selected the above nine images based on four factors: 1) Area of coverage, 2) Date, 3) Cloud-free and 4) Suitable Environmental Quality index (highest for the year). All of the images featured my area of interest, the islands and peninsula where the naval base is located. I had already mapped the area using both Landsat and DG imagery in GE. I identified the naval base from the numerous tags placed by GE naval snoops. They are able to easily identify ships and naval infrastructure using DG's hi-res images. So, back to our PHOTINT exercise.

The Jun 2006 DG image is the one found in GE. I did the overwhelming majority of my mapping of this area using it as my base image and supplemented with Landsat and the DG catalog images to complete my project. After assembling the above date-ordered sequence of images and we can begin the PHOTINT of our area of interest.

Oct 2002 - No protective breakwaters built yet. The site of the naval base is undergoing development, but the small islands scattered about the bay remain unattached.

May 2003 - A breakwater connecting the peninsula and the three southern islands has been built. Not too much other development has happened.

Nov 2004 - What a difference! All of the breakwaters are in place between the islands. The two lengthy piers, from the northern shore, are being built. Still no piers at the naval base proper.

Aug 2005 - All of the piers have been built. The two northern ones and three smaller ones at the base.

Jun 2006 - This is the DG image found in GE. The clouds obscure the two long piers. However, using the other images from previous years, I was able to map them successfully.

Jan 2007 - What happened to the middle pier? Maybe they needed more space between the two outer piers. A final observation concerns the peninsula itself. Apparently, submarines are kept beneath the peninsula. It is riddled with tunnels, some big enough for a submarine (based on GE naval snoops descriptions).

Now, wasn't that interesting? Using a little imagination, creativity, organization, ingenuity and PHOTINT skills, we all learned about the development of a portion of the Ya Long Naval Base. Imagine what the professional intel snoops are able to glean from the real hi-res images?

Enjoy!

PS - If it appears that I am treating a very sensitive and serious subject lightly, that is not my intent. All of us curious sorts that spend hours poring over DG imagery in GE conduct our own PHOTINT. We find aircraft, ships, vehicles, military sites and much more because it interests us. Perhaps in our youth, we too were snoops.

Dao Bach Long Vi VN - A Fancy Map!

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!