Wednesday, April 8, 2009

Taal VolcanoTHE FALSE PEAK OF TAAL VOLCANO

Taal Volcano is unique in the world. It’s a volcano—an active volcano. It has one large crater and that crater is filled with water making the crater a crater lake. On the lake is an island. It’s a tiny island but it is an island.

So far, it’s a description of a volcano with a single lake that has a tiny island.

Now, add this. This volcano is also in the middle of a lake. This lake, obviously, is larger than the entire volcano. That makes the volcano an island in this larger lake.

Now it’s complete. In the Philippines is a lake. On that lake is an island. That island is a volcano. On that island volcano is a smaller lake and on it, is another island. The smaller island is not a volcano but the island it’s on is. That volcano’s name is Taal.

Isn’t that unique?


Taal volcano (pronounced as two syllables: TA-AL; “TA” as in tar and “AL” as in alex) is considered to be the smallest active volcano in the world today. Signs of its activity will be visible if you take the boat tour and walk on the volcano island itself. You’ll spot fumaroles. A fumarole is a vent in the Earth’s surface from which steam and volcanic gases are emitted. (The Latin root of “fumarole” is fumus meaning smoke. In Spanish, “fumar” means to smoke.)

fumarole, Taal Volcano The volcano is 60 kilometers (nearly 40 miles) southeast of the city of Manila proper. Metro Manila’s population creep has nearly halved that distance. For example, some of metro Manila’s affluent inhabitants live only 40 kilometers (25 miles) away from the volcano. For comparison, this is the distance between Chicago O’Hare airport to Chicago’s downtown area (the Loop).

Its last major eruption occurred in 1965, or 44 years ago. Local inhabitants are willing to live within its proximity. There’s even a tourist resort based in the volcano island itself. With the exception of the fumarole photo, the other photos in this post were taken on 7 April 2009 from the same orientation—north facing southwest (approximately 210 degrees).

THE FALSE PEAK

To the casual observer, Taal’s peak seems obvious. Look at the first photo again (reproduced below). It’s a panoramic view of the entire volcano island. Can you see its peak?

Taal Volcano

The next photo below shows another view of the island from a higher elevation. Can you still see its peak? Is the peak on the left or right side of the island?

Taal Volcano

The next photo identifies the false peak. The peak that appears to be the volcano crater is an illusion. In this photo, the volcano’s actual crater is located between the left end and center of the island. The crater (which contains water and is a lake) is at ground level but the water level, naturally, is a little lower. The crater lake, therefore, is not visible in these photos. The illusion is explained at the end of this entry. The illusion, namely the false peak, has a name. It’s called Binintiang Malaki.

Taal Volcano

To enlarge any of these photos, simply click on it. To return to this page, click on the [left arrow] of your browser.

THE VISUAL ILLUSION EXPLAINED

If you review photos of Taal on sites around the web, you’ll realize how frequently this error occurs. The illusion mars what would otherwise be accurate captions of beautiful photos.


Here are several sites that fell prey to the illusion:

Back in the Islands
Taal Volcano













e-Philippines Adventure Travel and Destinations
Taal Volcano









TrekEarth The photographer-author unfortunately began his photo’s description by stating that “Taal Volcano (at the foreground, cone-shaped) has been called the smallest active volcano in the world.”
Taal Volcano









To enlarge any of these photos, simply click on it. To return to this page, click on the [left arrow] of your browser.

In each example above, it seems that the false peak was incorrectly identified as either the peak of the volcano or the volcano itself.

To understand why this happens, one must know that most trips to the volcano island originate from the north (frequently from the town of Talisay). Tagaytay City which sits on the ancient rim of the original volcano (before it blew itself apart) also lies to the north of Taal. If the face of a clock were superimposed on the area, Tagaytay City and Talisay would be at approximately 11 and 1 o’clock, respectively. Equally important, one must realize that most photographs are taken from those locations as well.

LOOK AT THESE IMAGES

Below is a satellite image of the area (courtesy of Google Maps). North is at 12 o’clock.

Taal Volcano

To enlarge any of these photos, simply click on it. To return to this page, click on the [left arrow] of your browser.

Below is a terrain image of the area (also courtesy of Google Maps). Again, north is at 12 o’clock.

Taal Volcano

Finally, below is the same terrain image rotated so that north is at about 6 o’clock. Note how the island is viewed. Note that the right side of the image shows the false peak of the volcano. The actual crater (i.e., the crater lake) sits betwen the left side and center of the image. Can you visualize it? If you can, then you understand why most observers and photos mistakenly think that the right side of the island is the volcano peak or even the volcano itself.

Taal Volcano

Several links to related photos, maps, and websites

Let’s not save the best for the last. This blog entry was taken from the website of the Astronomical League of the Philippines. It has better photos of fumaroles. It shows Binintiang Malaki (the false peak). Best of all, it has photos of Crater Lake and the tiny island on it!

This description of Taal came from the Public Information Office of the Jet Propulsion Laboratory (JPL) on November 18, 1994
This is an image of Taal volcano, near Manila on the island of Luzon in the Philippines. The black area in the center is Taal Lake, which nearly fills the 30-kilometer-diameter (18-mile) caldera. The caldera rim consists of deeply eroded hills and cliffs. The large island in Taal Lake, which itself contains a crater lake, is known as Volcano Island. The bright yellow patch on the southwest side of the island marks the site of an explosion crater that formed during a deadly eruption of Taal in 1965. The image was acquired by the space shuttle Endeavour on its 78th orbit in October 1994. The image shows an area approximately 56 kilometers by 112 kilometers (34 miles by 68 miles) that is centered at 14.0 degrees north latitude and 121.0 degrees east longitude. North is toward the upper right of the image.
Click here to see the image.

Click here to read a comprehensive background on Taal. It appears that this blog entry identifies the correct crater although it doesn’t specify each photo to the geological feature.

If this entry helped observers understand the true topography of Taal Volcano, it has accomplished its purpose.




Sphere: Related Content

Monday, March 30, 2009

tag cloud text cloud rules of evidence justice pronoveTAG CLOUDS & TEXT CLOUDS

Flickr is among the top 40 most popular websites on the Web today. It’s not surprising since it serves a very useful purpose. Instead of attaching photos to an email, a person can simply upload the photos to Flickr and then refer people to it. Most photos are meant to be shared and after it’s been seen, it’s archived. In short, most photos have a very brief life. Look at them once then move on.

Aside from the typical user, bloggers—like me—use Flickr as a photo repository. As of November 2008, it claimed to host more than 3 billion images. That’s according to Wikipedia (a site even more popular than Flickr).

(You can enlarge any image by clicking on it. To return to this page, click on the back-arrow of your browser or press the Backspace key on your keyboard.)

Flickr was the first popular website that used tag clouds.

What’s a Tag or Text Cloud?

It’s a visual depiction of the word content of a website. The most frequent words are depicted. Additionally, each word in the cloud is emphasized according to its frequency. Numerous variations exist but this is the basic idea.

What’s the difference between a tag and text? Tags are text that are placed at strategic locations in the code that comprise webpages. Tags are important because search engines like Google use tags to add webpages to its database. For an example, look at the bottom of this blog entry. Its tags are: analysis, cloud, depiction, father, flickr, google, photo, psychology, seo, tag, technorati, text, visual, wikipedia.

Since I created those tags, they’re referred to as user-generated tags.

Let’s examine a text cloud example that was created from this paragraph. The word “word” appears seven times. In this paragraph’s text cloud (shown below), the word “word” is emphasized by its size and thickness. The word “word” is the largest and thickest word in this paragraph’s text cloud.

This text cloud was created through Wordle.

The first text cloud above is a one-time depiction of some content found in one of my father’s published books. “One-time” means that it’s a snapshot. It’s a static depiction of content. Dynamic clouds also exist, like the one at Flickr’s. Dynamic clouds update at periodic intervals or on demand. Dynamic clouds are typically created by third-party web-based services such as Technorati or Wowzio. These services are currently free.

This blog’s dynamic cloud is hosted by Technorati. It’s on the left sidebar. The other blog that I maintain has a dynamic cloud that’s hosted by Wowzio. I use two different providers because providers are not always operational. I wanted to spread the risk so if this blog’s cloud doesn’t appear, it will in the other blog.

Cloud Psychology

Clouds are an example of innovation being spurred by a new medium (the Web) running on technology (the Internet). A Stanford student explained it this way:
When we look at a text cloud, we see not only an informative, beautiful image that communicates much in a single glance, we see a whole new perspective on text.

TagCrowd is taking tag clouds far beyond their original function:
  • as topic summaries for speeches and written works
  • as blog tool or website analysis for search engine optimization (SEO)
  • for visual analysis of survey data
  • as brand clouds that let companies see how they are perceived by the world
  • for data mining a text corpus
  • for helping writers and students reflect on their work
  • as name tags for conferences, cocktail parties or wherever new collaborations start
  • as resumes in a single glance
  • as visual poetry
The list goes on and continues to grow.

In the future, TagCrowd will develop into a suite of experimental tools and tutorials that empower social and collaborative uses for text clouds and related visualizations.

Our mission is to push the innovation envelope in online and face-to-face communities of all stripes.
Would you like to play with clouds?

These three sites create static clouds. Enjoy!
  1. Wordle — this is my favorite
  2. MakeCloud
  3. TagCrowd


Sphere: Related Content