Monday, May 30, 2016

Memorial Day 2016

“It is the Soldier, not the minister
Who has given us freedom of religion.
It is the Soldier, not the reporter
Who has given us freedom of the press.
It is the Soldier, not the poet
Who has given us freedom of speech.
It is the Soldier, not the campus organizer
Who has given us freedom to protest.
It is the Soldier, not the lawyer
Who has given us the right to a fair trial.
It is the Soldier, not the politician
Who has given us the right to vote.
It is the Soldier who salutes the flag,
Who serves beneath the flag,
And whose coffin is draped by the flag,
Who allows the protester to burn the flag.”

Saturday, April 23, 2016

Travel Times Over the Past 200 Years

The classic Atlas of the Historical Geography of the United States shows exactly how travel times across the United States have evolved over time. Back in the early 1800s, without easily navigable roads or railroads, even a journey from New York to Washington, DC, was a multi-day affair.

Map of travel times in 1800 and 1830. (Hathi Trust)

Over time, that slowly improved. Construction on theNational Road, which stretched from Cumberland, Maryland, across the United States, began in 1811 and continued through the 1830s. The advent of the steamboat also made it easier to use rivers.

The big advance, however, came through trains. By 1857, railroads had improved travel times significantly — culminating with the development of the Transcontinental Railroad in 1869. Even in 1857, travel was easier, thanks to the railroad system.

Map of travel times in 1857. (Hathi Trust)

By 1930, railroads had successfully compressed travel times to a couple of days versus the many weeks it took in the 1800s.

Map of railroad travel times in 1930. (Hathi Trust)

These maps don't just show the rapid pace of technological progress, however. They also show how that progress advanced unevenly, in fits and starts. Railroads didn't reduce travel times right away — they still required significant infrastructure investments, ranging from laying down tracks to building tunnels. That took decades.

The same thing happened to airline travel. This map of air travel times in the 1930 shows it was a huge advance on railroads. But it was still significantly slower than air travel is today:

Map of airline travel times in 1930. (Hathi Trust)
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Friday, April 22, 2016

Earth Day

Happy Earth Day world! We only have one so let's look after it!

The 10 most surreal landscapes in the world

While some may believe the perfect travel destination consists only of sun, sea and sand, for those with a more adventurous streak, here is a collection of the most surreal and mysterious landscapes on earth. These are places that have intrigued visitors, baffled scientists and captured the imagination of local people for centuries.
Lake Hillier, Australia

This violently pink saline lake can be found on Middle Island in the Recherché Archipelago, off the coast of Western Australia. While only 600 metres long, the startlingly-coloured lake resembles a piece of Pop Art on the otherwise uniformly green island. The cause of its pink hue continues to baffle scientists. Some experts think it is caused by the low nutrient concentrations and different types of bacteria and algae, while others suggest the pink colouration comes from a sea salt and nahcolite deposit reaction.
Dallol, Ethiopia

Resembling the scenery of a video game or sci-fi film, Dallol’s volcanic landscape in the Danakil Depression is a geological phenomenon. Its luminous, otherworldly appearance is a result of acidic hot springs, sulphur, gas geysers and spectacular salt formations. However, a note of caution to those planning a visit to this extraordinary crater: the climate in Dallol registers the hottest temperatures of any inhabited area on earth, with average summer highs of 46C. The colourful lakes are, in many cases, toxic and the sulphurous vapours make it difficult to breathe.
Lake Natron, Tanzania

This salt and soda lake in the Arusha Region of northern Tanzania evaporates completely in the summer, leaving an astonishingly blood-red lake floor, thriving with salt-loving organisms and algae. On top of the dramatic scenery, the dry lake is an important breeding area for more than a million flamingos. However, when full, the highly caustic lake is deadly to any animals not adapted to it. One of the most inhospitable environments on earth, Lake Natron is best viewed from the air.
Zhangye Danxia Landform, China

This landscape of surreal, psychedelic colours and shapes has to be seen to be believed. Known as the “eye candy” of Zhangye, the 400 square kilometre geological park can be found in the Gansu Province in central north China. Danxia landform, a type of geomorphology unique to China, is formed of coloured sandstones and conglomerates largely from the Cretaceous age 66 million years ago. Geologists believe it is a result of movement in the Earth’s crust, which makes rock layers appear in different colours, sizes and patterns.
Atchafalaya Swamp, US

This captivatingly eerie swamp in Louisiana stretches across 5,700 square kilometres, making it the largest in the United States. The vast expanse of wetlands, bayous and marshes is home to beavers, bears, alligators and dozens of endangered bird species. Humans have also inhabited the swamp for hundreds of years, from Native Americans, to fleeing French colonists to present-day Cajuns. Boats can snake through aisles of haunting, moss-draped cypress trees that tower above the water.
Joshua National Tree Park, US

This national park is a gem in south-eastern California that attracts more than a million visitors ever year. Comprising two very distinct desert systems, the Colorado and the Mojave, the park flaunts a variation of vast, parched wilderness to the east and sandy plains adorned by the otherworldly, giant branching yuccas – Joshua Trees – to the west. They are the largest type of yucca and are endemic to the Mojave desert. Numerous visitors come to the park for its fantastic rock piles, formed more than 100 million years ago, which offer many opportunities for climbing and hiking.
Tsingy de Bemaraha, Madagascar

A labyrinth of towering limestone needles, Tsingy de Bemaraha National Park is a Unesco World Heritage Site. Situated in the Melaky Region on the western coast of this spectacular Indian Ocean island, the park comprises 1,575 square kilometres of dramatic canyons, gorges, and largely untouched forests. Its abnormal topography of vertically steep monoliths makes the Tsingy de Bemaraha site home to an exceptionally high number of endemic plant and animal species.
Socotra, Yemen

A hub of biodiversity in the Indian Ocean, Socotra is an archipelago of four islands located some 200 miles south of the Arab peninsula. Its geological isolation and fierce heat has left it with some of the highest numbers of unique species of anywhere in the world. Nearly 40 per cent of all plant species on the islands are found nowhere else on Earth. Among the most famous and distinctive of these is the dragon blood tree, which bears the remarkable appearance of a giant green mushroom. The tree’s resin, called dragon blood, is highly prized by locals and used as medicine to treat almost all ailments. However, with Yemen currently on the Foreign Office’s no-go list, it’s best to appreciate Socotra’s strange beauty on screen only.
Cappadocia, Turkey

The phantasmagorical landscape of the Göreme National Park in Cappadocia, is a product of both natural phenomena and human intervention. Volcanic eruptions and erosion have contributed to the formation of the fairy-tale-like rock cones, pillars and mushrooms stretching up to 40 metres high. Meanwhile, human hands developed a network of extraordinary caves and tunnels under the rocks some 3,500 years ago. These underground settlements cover over 100 square miles, and while most of the cave dwellings are currently unoccupied, some still serve as homes and others as hotels.
Salar de Uyuni, Bolivia

The Earth’s largest salt flat, situated near the crest of the Andes in southwest Bolivia, may give the visitor the illusion of being able to walk on air. This breath-taking expanse of salt crust covers more than 10,000 square kilometres, essentially resembling a giant mirror. According to the legend of the Aymara people of the Andes, the Salar is formed of the tears of the mountain goddess Tunupa after she was abandoned by her husband Kusku.

Wednesday, April 20, 2016

David Rumsey Maps

Download 67,000 Historic Maps (in High Resolution) from the Wonderful David Rumsey Map Collection.

Stanford University’s been in the news lately, what with expanding its tuition waiver last year and now facing renewed scrutiny over its ultra-low admissions rate. These stories have perhaps overshadowed other Stanford news of a more academic nature: the arrival of the David Rumsey Map Center, which celebrated its grand opening yesterday and continues the festivities today and tomorrow. While these kinds of university improvements are rarely of much interest to the general public, this one highlights a collection worth giving full attention. Well, for those of us, that is, who love maps.

You do not need to be a Stanford student or faculty or staff member to access the vast treasures of the Rumsey Map collection, nor do you need to visit the university or its new Center. Since 1996, the Rumsey collection’s online database has been open to all, currently offering anyone with an internet connection access to 67,000 maps from all over the globe, spanning five centuries of cartography. Rumsey’s holdings constitute, writes Wired, “the dopest map collection on Earth,” and though its physical housing at Stanford is a huge boon to academic researchers, its online archive is yours for the browsing, searching, and downloading, whoever and wherever you are.

Pages like the 1867 map “Twelve Perspectives on the Earth in Orbit and Rotation,” further up, contain detailed publication information, the ability to zoom in and examine the tiniest details, and an “export” function allowing users to download a variety of resolutions up to 12288 pixels. (The same holds true for all other maps.) There’s also a new feature for many maps called “Georeferencing” (see a short introductory video above), which matches the map’s contours with other historic maps or with more accurate, modern satellite images.

In the case of “Twelve Perspectives on the Earth in Orbit and Rotation,” the georeferencing function returns an error message stating “this is not a map.” But in terrestrial images, like the topographical map of the Yosemite Valley above, we can choose specific portions to georeference, use the “visualize” function to see how they match up to contemporary views, and conduct an accuracy analysis. (Georeferencing requires sign-in with a free account, or you can use your Google, Facebook, or Twitter log-ins.) Georeferencing is not available for all maps, yet. You can help the Rumsey collection expand the feature by visiting this page and clicking the “Random Map” link.

The Rumsey Collection contains a seemingly inexhaustible supply of cartographic images, such as the colorful aerial view of New York City from 1900, above, and the 1949 composite map of the Soviet Union, at the top of the post. In addition to the maps themselves—most works of art in their own right—the database is full of other beautiful images related to geography, such as the fabulous, full-color title page below for the 1730 Atlas Novus sive Tabulae Geographicae by Matthaeus Seutter.

David Rumsey—currently President of the digital publishing company Cartography Associates—began collecting maps and “related cartographic materials” in 1980. Since then, his physical collection has grown to include over 150,000 maps, to be housed at the Stanford Center that bears his name, and he has received several awards for making his collection available online. The cartography enthusiasts among us, and the hardcore scholars, can likely look forward to many more maps appearing in the web archive. For now, there’s no shortage of fascinating material.

On the site’s homepage, they highlight these areas worth exploring:

The historical map collection has over 67,000 maps and images online. The collection includes rare 16th through 21st century maps of America, North America, South America, Europe, Asia, Africa, Pacific and the World.

Popular collection categories are celestial, antique atlas, globe, school geography, maritime chart, state, county, city, pocket, wall & case, children’s, and manuscript maps. Search examples: Pictorial maps, United States maps, Geology maps, California map, Afghanistan map, America map, New York City map, Chicago map, and U.S. Civil War maps. Browse map categories: What, Where, Who, When. The collection is used to study history, art, genealogy, explorations, and family history.

Get to browsing… and georeferencing….

Saturday, March 19, 2016

Happy Vernal Equinox 2016!

 But What Does That Mean?

Joe Hanson not to scale.

Saturday is the vernal equinox! Well, Saturday night is, depending on where on Earth you are. The moment happens at 04:30 UTC on March 20 this year, which is, for example, March 19 at 10:30 p.m. Mountain (U.S.) time, where I live.

PHIL PLAIT writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!

But what does that mean, exactly? Why,let my friend Joe Hanson explain it to you in an episode of “It’s Okay to Be Smart”

The equilux point he makes is a good one. It’s even worse than he describes; our atmosphere scatters sunlight, spreading it out. That’s why we have twilight; the air is lit up even when the Sun is well below the horizon. There are different definitions for twilight depending on what you mean by it, but a fair one is when the center of the Sun is about 12° below the horizon. The Sun moves across the sky at about a degree every two minutes, so twilight is bright for very roughly a half hour before sunrise and after sunset.

So equilux can be hard to define if you dive into the details about it.

One thing I always notice this time of year, too, is that the Sun seems to set noticeably farther north every day. At the December solstice it’s as far south as it can be on the horizon for Northern Hemisphere observers. At the June solstice it’s as far north as it gets. At the equinoxes it sets due west.

But the rate at which the sunset point moves north from winter to summer changes. It’s very slow at first, then speeds up to a maximum at the equinox, then slows again. So right now, not only is it setting farther north every day, the amount it moves north every day is largest. Starting after the equinox it begins to slow, and stops at the solstice (which literally means “the Sun stands still”).

If you’re mathematically inclined, the point on the horizon where the Sun sets is like a sine wave, moving south to north and back again with a period of one year. The speed at which that point moves along the horizon is the derivative of that, which is a cosine curve. Call due west on the horizon 0°, north +90°, and so on. When the Sun sets due west, on the equinox, the sine value is 0, but the cosine is maximized. That means the change in the position where the Sun sets is moving at its fastest speed. At the solstices the sine is maximized (the actual value depends on the Earth’s tilt and your latitude) but the absolute value of the cosine is minimized at 0, and then the cosine switches sign. In other words, the sunset point slows to a stop and then reverses direction the next day.

This gets worse because the Earth’s orbit is an ellipse, which messes with things, as Joe pointed out in his video. But it’s close enough. People make analemma photos all the time, showing the Sun’s position in the sky over the course of a year. I’d love to see the same thing, but instead showing the Sun just at sunset every day of the year. Then this speeding up and slowing of the Sun’s sunset point would be obvious. That’d be quite an effort, though, and I’ve never seen one made. Any takers?