Showing posts with label Ikonos. Show all posts
Showing posts with label Ikonos. Show all posts

Tuesday, December 30, 2008

Thoughts - Rapa Iti's Hydrographic Layer

Rapa Iti Island - Ikonos Image (1-55,000) Modified

Rapa Iti Island - Ikonos Image (1-55,000)


Rapa Iti Island - Other Precision Map (Ikonos Image) Hydrography Layer (1-55,000) Modified>

Rapa Iti Island - Other Precision Map (Ikonos Image) Hydrography Layer (1-55,000)

I believe Rapa Iti's hydrographic layer is almost complete. I always QC my digitizing before I determine a layer finished. I am watching the Pacific Life Holiday Bowl (score Okla St 31 and Oregon 42) and composing this post. A few moment ago my mother-in-law asked what my map showed. I explained that I had mapped all of the places where water would flow during a rain storm. She thought that was interesting, but liked the colors best.

The QC of this layer will involve a final classification of the streams. They will be classified as permanent streams identified by vegetation, stream width and visible water. Any or all of these characteristics evident will cause me to classify the stream as permanent. All other streams will be classified as intermittent streams.

This system of classification will have to do short of me visiting the island for a month during the rainy season and spending the time hiking to various points about the island to study water flow. Oh well, one can dream.

Enjoy! And Happy New Year!

Monday, December 29, 2008

Thoughts - Digitizing Rapa Island's Hydrography Layer

Rapa Island, North Shore - Ikonos Image with Hydrography Layer (1-1,250)

Rapa Island, North Shore - Ikonos Image with Digitized Hydrography Layer (1:1,250)


Rapa Island, North Shore - Other Precision (Ikonos) Map with Hydrography Layer (1-1,250)

Rapa Island, North Shore - Other Precision (Ikonos) Map with Digitized Hydrography Layer (1:1,250)

Sure, I've been busy with family, friends and 12 dozen tamales served all day Christmas day at my home. Come Christmas evening I was still entertaining guests and wishing I could continue working on my current mapping project, Rapa Island. I have mapped this island a number of times, each time not completely satisfied with the finished project. So I've decided to work on this island one more time. First I redigitized the shoreline working at scales between 1:1,250 to 1:850 using a hi-res Ikonos image. After completing the shoreline, I decided to work on the island's hydrographic layer. Initially I've classified each valley as a potential stream course. The island has a number of permanent streams fed by frequent rain storms and springs. Most of the streams I've currently mapped will be reclassified as intermittent.


Rapa Island - Other Precision (Ikonos) Map with Hydrography Layer (1-52,500)

Rapa Island - Other Precision (Ikonos) Map with Hydrography Layer (1:52,500)

I've mapped most of the hydrographic layer over the last 5-days, actually over the last 5-evenings. The hydrography of the western portion of the island remains to be digitized. I hope to have the layer completed within the next few days. When it is finished, I intend to digitize the vegetation layer next. I'll keep you informed as to my progress.

Enjoy! Merry Christmas and Happy New Year!

Friday, July 13, 2007

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

Niumaroro Atoll - Image (Landsat)

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


Nikumaroro Atoll - Map

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 - Image

Nikumaroro Atoll - ESA Ikonos Image (04-2001)


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

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!

Monday, July 2, 2007

Nikumaroro Atoll KR - Third Time is the Charm

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

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)


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!