Showing posts with label surveying. Show all posts
Showing posts with label surveying. Show all posts

February 21 – Happy Birthday, Edouard-Gaston Deville

Posted on February 21, 2014


Have you heard of phototopography? How about photogrammetry?

Yeah, me neither! Actually, even my spell checker hasn't heard of the first one!

But actually, this field (which has two names, and which was first perfected by today's birthday boy) is really important—and even something we take for granted:

It is the use of photography to make maps.

Some descriptions of photogrammetry say that it is a non-contact method of making maps. In the past, people had to actually walk or sail in order to survey land, in order to make the measurements that assured that the map would be fairly accurate and therefore useful.


Who was Deville?

Born in France, Edouard-Gaston Deville attended naval school, served in the French navy, and learned about surveying. He moved to Canada at age 25 and began to work as a surveyor and astronomer. He was quickly promoted to top surveyor, and for many years he directed Canadian surveying activities.

So, you know what Canada is like, right? It is the second largest nation in the world, after Russia, and a lot of it is high mountains or remote Arctic lands. At the time that Deville developed new surveying techniques, in the late 1800s, there was no Google Earth or satellites in space, of course, and even the airplane hadn't yet been invented. However, photography was nearly half a century old and was revolutionizing many aspects of life. Deville wanted to use it to survey Canada's mountains in a faster, cheaper way.

He had to design a rugged but lightweight field camera that could be carried up to the top of a mountain. Once the camera was in place on a mountain peak, the surveyors pointed the camera at the horizon and took panoramic photos of the nearby peaks. Each photo shot was carefully recorded with a measurement of the angle of the camera to the survey station. Surveyors did all their measurements and took all their photos during the short Canadian summers, and during the longer winters they would make their calculations and draw their maps. The first such mountain survey was started in 1886.

It turned out that, not only were these techniques much faster than traditional surveying techniques—and cost only about a third as much—the results were more accurate. Soon Deville became a sought-after expert in mountain surveying, and people all over the world asked his advice, read his pamphlets and textbook, and copied his camera and techniques.

As you can imagine, when air flight became possible, surveyors could use Deville's camera to create aerial photos. This helped Canadian surveyors accurately map the flat-but-remote northern areas of the nation.





This is Mount Deville, named
for today's birthday boy.
It is in Yoho National Park in
Canada--and, oh, my!--is that
place GORGEOUS!!!

More on maps...

  • Check out these child-drawn maps created in the 1700s and 1800s. Students often carefully copied and colored maps in order to learn geography. Do you think the parts that don't match modern maps are inaccurate because the kids wereyou knowjust kids, or do you think that they were pretty accurate copies of what people knew back then?

  • Use Google Earth to create a map of your own neighborhood.



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November 9, 2011 - Sagan Day / Banneker's Birthday



This is the third annual Sagan Day, a chance to remark on and remember the contributions of the astronomer and science communicator Carl Sagan. He was one of my heroes (I use past tense here because he is, sadly, deceased – but I suppose that he still IS one of my heroes, really!), so I have to give his special day a shout-out. Find out more about him on this or this other post.

and...
I had to find another astronomer and scientist to honor on Sagan Day. So let's give warm birthday wishes to Benjamin Banneker!

Born on this day in 1731, Benjamin Banneker didn't have the cushiest life. The grandson of a slave and (possibly) an indentured servant, and the son of a runaway slave, Banneker may have been taught to read and observe the night sky by his grandmother, Molly. He was given a bit of formal education by a Quaker farmer who ran a small school, but when he was old enough to help on his own family's farm, his formal education was over. However, the Quaker man was nice enough to loan Banneker books, and Banneker taught himself math and astronomy by reading borrowed textbooks. Later, as an adult, Banneker continued to study astronomy using books and equipment loaned to him by another Quaker neighbor.

Banneker was hired as a surveyor and eventually was part of a survey team creating the boundaries of the District of Columbia, land that Maryland and Virginia ceded to the federal government of the U.S. for the purpose of building the capital city (Washington, D.C.). Banneker was able to use astronomical observations that helped the team figure out the starting point of the survey, and he maintained a clock used to relate points on the land to positions of certain stars at specific times. All his life, Banneker predicted solar and lunar risings and settings and also solar and lunar eclipses; over the years he compiled several almanacs containing these predictions, weather forecasts, and other important information.

It is interesting to note that, although Banneker was an accomplished man—and certainly for his race at that time!—the truth didn't seem to be enough for people. There have been a lot of stories told about Benjamin Banneker that have made him part myth or even urban legend. For example, here is a great little story:

As I said, Banneker worked on the survey team that created the boundaries for Washington, D.C. The architect/designer/planner of the city was Pierre L'Enfant, who was said to have had a bit of a temper. When changes were made to L'Enfant's plan, he threw a fit and was fired from the job. The story goes that L'Enfant was so angry that he took the completed plans with him, and that the architects and builders would have to start from scratch again—except Banneker saved the day! He was able to recreate the plans from memory and thus saved the new U.S. government a lot of money!

Which is great, except for the fact that apparently it didn't happen. According to historical evidence, Banneker left the job by the time L'Enfant was completing his plans, several people had copies of the plans at the time of L'Enfant's dismissal, and Banneker never saw the plans, let alone recreated them from memory.

Almost everything about this piece is wrong.
Thomas Jefferson didn't suggest Banneker for
the commission, nor was he on the commission.
Banneker did made a clock, but it wasn't the first clock in
America, not by a long shot!
There are other exaggerations and fictions told about Banneker. Which seems strange to me, since the reality of Benjamin Banneker is already very interesting and wonderful!