EVS-Islands

Pai-Ch'uan Lieh-Tao

Baiquan Liedao (Pai-ch'uan Lieh-tao) (25°58'N., 119°55'E.), lying about 11 miles S of Matsu Liehtao, consists of two islands and several islets and rocks.

Dongquan Dao (Tung-chu Tao) (25°58'N., 119°58'E.), the E island of the group, is 114m high and precipitous; islets and dangers lie within 0.75 mile NW and 1 mile NE of the island.

A light is shown from a round tower on the NE end of the island and a signal operates from the tower.

Xiquan Dao (Hsi-chu Tao) (25°59'N., 119°56'E.), the W island of the group, is 191m high. Its summit consists of three rounded hummocks, on the center and highest of which is a boulder; the SW slopes of the ridge are strewn with sand and show white in misty weather when little else of the island is visible.

P'o-lang Shih, 16m high, lies at the outer end of a rocky ridge which extends 0.5 mile SW from the W point of the island; this rock and a 13m high rock on the ridge are prominent. Sand banks, with charted depths of 5.4 to 10m, extend up to 4 miles SW of Hsi-chu Tao.

Caution.—A prohibited area, which may be fouled by fishing stakes, lies about 4 miles SE of Tung-chu Tao. (SD Pub-157)

I said to myself, "Avoid controversial islands. Select an island of little or no consequence." So what did I do? I selected a group of islands located off of the eastern coast of China which are claimed by the Republic of China (ROC). The actual map work was straight forward and the map product was simple and fast to construct. But I failed on the controversial islands aspect of the project. This group of islands is located to the south of Matsu Island, another island claimed by the ROC. These small rocks are continually contested for ownership between PRC and ROC. So far ROC has control and the PRC, although formally complaining, abides by the status-quo. They are potential flashpoints. They would be an interesting destination for an intrepid traveller.

view Pai-Ch'uan Lei-Tao on Google Maps

Enjoy!

Labels: China, Digital Globe, EVS, island, Landsat, Marplot, Pacific, Taiwan

Posted by Mr Minton at 3/23/2007 01:36:00 AM | Permalink | Comments | links to this post

I have studied the Limits in The Seas (LOS) for some time. While working with island maps I found that these listings display both timely and difficult to obtain information. There are at least two sources for this information - The US Department of State and Florida State University Law Library. Both sources appear to offer the same documents.

Since I have done extensive mapping in and around Taiwan, I looked at that country's baseline data. What is a baseline? It is the internationally agreed upon baseline that all other maritime boundaries are drawn from. Consequently, it is the "mother" of all maritime boundaries. One of the documents lists detailed explanations of how baselines are determined. Needless to say, it is an extremely exacting science and one that is open to a wide variety of interpretations..

This is a table of Taiwan's Baseline coordinates. The main portion contains the baseline that encompasses Taiwan proper. Two shorter baselines cover island groups to the south. The document is in PDF format and the coordinates are in degrees-minutes and decimal-seconds. Other documents list the coordinates in degrees-minutes-seconds. This format is not the most widely used for digital mapping, but it can be converted into degrees-decimal.

Each document includes a map(s) of the baseline(s). The maps are small scale and gives one a good idea of the alignment of these unique maritime boundaries.

Being the consumate "data-hound", I figured out a way to extract the baseline coordinate table from the PDF document, format it's data (lat/lon coords) using MS Word. That data is transferred into MS Excel. It is converted into two Marplot compatible layers of vector information. One layer is the Baseline line (polyline) and the second layer is the Baseline points with names. After preparing them within MS Excel, I import them into Marplot where I can choose to display them whenever or however I wish.

Enjoy!

Labels: Limits in the Seas, LOS, Marplot, Taiwan

Posted by Mr Minton at 3/22/2007 06:15:00 AM | Permalink | Comments | links to this post

Pulau Romang Island Group

I've been working on this group of islands for the past few weeks. All of the layers of information are digitized. This week I will bring the digitized files into Marplot and construct my map. After the map is complete, I will create contours. Finally, I will publish the completed images.

Improved Rapa Island Shoreline and Contours

This project is also in the final stages. I discovered Digital Globe hi-res imagery on Google Earth covering most of the island. The improved shoreline is complete. I will create as many additional layers of information as the imagery will allow. The western portion of the island is cloud covered. DG does have a cloud-free image. Maybe they will let me use it? Unfortunately the SRTM data covering the island has large voids that I will have to extrapelate the course of the contours. I will need to find a reasonable topo of the island (fat chance!) or do my best guess-timation of the missing contours. It should be a challenge.

Cabrits NP Dominica Island

This is part of a viewer's senior project. You all know that I do work for free. If it is non-commercial, within my abilities and the time-frame is mutually agreeable, I'll create an EVS precision project for you to use. It turned out this area has Digital Globe imagery to work from. Consequently, the land use layers were detailed and complex. The SRTM data had a void that I had to guess-timate the contours. For the purposes of this student's project. the time constraints and the fact that I was working in uncharted areas of expertise, the guess-timate method was sufficent. I worked on this project off and on for over two weeks and am pleased with my efforts.

Other projects being worked on are Lindesfarne Island, UK and The Three Maria's located off the western coast of Mexico.

So many projects and not enough time.

Enjoy!

Labels: Digital Globe, digitize, EVS, Global Mapper, Google Earth, map, Marplot, SRTM

Posted by Mr Minton at 3/19/2007 06:06:00 AM | Permalink | Comments | links to this post