NOAA Teacher at Sea
Susy Ellison
Aboard NOAA Ship Rainier
September 9-26, 2013
Mission: Hydrographic Survey
Geographic Area: South Alaska Peninsula and Shumagin Islands
Date: September 18, 2013
Weather: current conditions from the bridge
You can also go the NOAA’s Shiptracker (http://shiptracker.noaa.gov/) to see where we are and what weather conditions we are experiencing.
GPS coordinates: 55o 12.442’ N 162o 41.735’ W
Temp: 9.6C
Wind Speed: 20.3 kts
Barometer: 994.01mb
Visibility: grey skies, foggy
Science and Technology Log
WHERE ARE WE? HOW DO WE KNOW?
As we float about all day collecting gigabytes of data to turn into charts, there’s ample time to reflect on the art and science of cartography, or map making. To me, maps are an elegant means for transforming the 3-dimensional landscape around us into a 2-dimensional story of our world using lines and points, geometric shapes, numbers, and a variety of colors and shadings. It’s science, technology, engineering, math, and, as always, a bit of magic! It’s quite amazing to think about the changes in mapmaking and our expectations for information from the first hand-drawn lines on small pieces of clay or in the dirt to the concatenated gigabytes of today.
Consider some of the earliest maps that have been found. Archaeologists have unearthed clay tablets in Babylonia that date back to 600 BC. These hand-sized clay tablets were simple line representations of local geography. Roman maps from around 350BC were utilized to provide information to conquering armies. Where were they heading; which villages were going to be conquered today?
http://www.datavis.ca/milestones/index.php?group=pre-1600
The earliest maps were, both literally and figuratively, flat; they were a 2 dimensional image of a world that was believed to be flat. That changed in 240 BC when Eratosthenes, who believed the earth to be a sphere, calculated earth’s diameter by comparing the length of noontime shadows at distant sites. No advanced computing power was used for this calculation! Once geographers and cartographers were united in their use of a spherical representation of the earth, the next challenge was how to project that spherical surface onto a flat page. Ptolemy, sometime around 100 AD figured this out. He went a step further, assigning grid coordinates (latitude and longitude) to the maps to use as identifiers. His latitude lines, rather than expressed as degrees from the equator, were categorized by the length of the longest day—not such a bad proxy for degrees north and south and certainly an obvious change as you head north or south. Longitude, instead of referencing the Greenwich Meridian as 0o, was set at 0 at the westernmost point that he knew. Much of his work was not used until it was rediscovered by monks poring through manuscripts in the 1300s. One monk was able to use the coordinates in these manuscripts to create graphic representations (maps!) of Ptolemy’s concepts. These were printed in 1477 as a map collection known as Geographia. It is almost mind-boggling to consider the efforts that went into this volume from its initial intellectual conception, to its rediscovery, to using some of the first printing presses to make multiple copies that were used to plan and guide some of our most amazing voyages of discovery. Ptolemy’s concepts were further refined when Gerardus Mercator invented a cylindrical projection representing globe on a map’s flat surface. Each refinement both changed and enhanced our view of the planet.
http://upload.wikimedia.org/wikipedia/commons/5/58/Mercator_World_Map.jpg
THERE MAY BE DRAGONS
Sailors set forth with maps using these concepts for many years, seeking out new lands and new wealth for the countries they represented. As they returned with new discoveries of continents, cultures, and meteorological conditions, they were able to replace some of the ‘dragons’ on maps with real information and add new layers of information on top of the positions of continents and oceans—an early sort of GIS (geographic information systems) process! In 1686, Edmond Halley created a map that incorporated the prevailing winds atop a geographical map of the world. A new layer of information that told a critical story. For a sailor navigating using the wind, the story this map told was incredibly useful. Further layers were placed on the surface geography as Johann Friedrich von Carpenter created the first geological map in 1778. This map included information about what was under the surface, including soils and minerals.
http://earthobservatory.nasa.gov/IOTD/view.php?id=8733
To me, perhaps one of the fundamental changes in how we represented the earth came in 1782, when the first topographic map was created. Marcellin du Carla-Boniface added still more layers of information to our ‘flat’ surface, including contour lines that were like slices of the landscape whose spacing indicated the slope of the feature. Suddenly, we were going from a 3-dimensional world, to a 2-dimensional image, and back to a system of symbols to represent that third dimension. More data, more layers, more information on that one sheet held in your hand, and a more detailed ‘story’ of the landscape. Each cartographical and technological advance has enabled us to put more information, with increasing accuracy, upon our maps. Go one step further with this and click on Google Earth. A 3-dimensional view on a 2-dimensional screen of 3-dimensional data. Go one more step as you use your smartphone to display a 2-dimensional image taken from a 3-dimensional Google Earth view, made using layers of information applied to a flat map image. It’s a bit more sophisticated than the original flat clay tablet—but it basically ‘tells’ you how to get from here to there. While the complexity of our world has not actually increased, the stories we are telling about our planet have increased exponentially, as has our ability for combining datum from a variety of sources into one, tidy little package.
This is a small piece of the first topographic map which included elevation information about surface features
http://www.datavis.ca/milestones/
THERE MAY BE DATA!
With each new technique and layer of information our ability to tell detailed stories with maps has improved. We can add data to our maps using colors—just look at a modern colorful weather map in USA Today if you want to see an example of this. Early cartographers used colors and shading to depict disease outbreaks or population numbers. Here on the Rainier, we use color variations to show relative depth as we survey the ocean floor. The final charts have lines to denote depth changes, just as lines on a land-based topographic map show changes in elevation.
So, you might be asking yourself at this point, ‘How does a history of mapping relate to mapping the coastline in SW Alaska?’ Why are we currently anchored out here near Cold Bay, Alaska? NOAA had its beginnings in 1807 when the first scientific agency, the Survey of the Coast, was established. Since then, NOAA’s mission has broadened to include the following “NOAA is an agency that enriches life through science. Our reach goes from the surface of the sun to the depths of the ocean floor as we work to keep citizens informed of the changing environment around them.” We are here as part of that mission, working through their National Ocean Service. You might not realize it, but almost every imported item you buy spent some part of its life on a ship. While Alaska’s coastline may seem a trifle remote, if you check out a map you might notice that it’s almost a straight shot from some of the ports in Asia to the west coast of the US.
The Alaska Maritime Ferry also passes through these coastal areas on its way to towns and villages. While these areas are, indeed, remote, they are united by a common coastline. The Rainier, in over 40 years of ‘pinging’ its way northward each season from Washington and Oregon, has mapped this coastline. That, to me, is an amazing feat!
Think of where we’ve come in our ability to tell stories about our landscape and how the intersection of all those stories has played a part in creating the world in which we live. I, for one, still delight in the most simple of maps, drawn on a scrap of paper or the back of a napkin, showing someone how to get from point ‘a’ to point ‘b’. Those maps are personal, and include the layers of information that I think are important (turn left at this house, turn right at that hill, go 2 miles, etc) and that tell the story I want to tell. We now have the ability to add endless layers to our mapping stories, concatenating ever more data to tell an amazingly precise version. In spite of this sophistication I hope there’s still a few dragons left out there!
If you want to know more, here’s some of the websites I looked at while researching this information:
http://oceanservice.noaa.gov/navigation/hydro/#1
http://specialprojects.nos.noaa.gov/welcome.html
http://www.datavis.ca/milestones/index.php?page=introduction
For a great cartographic mystery, check out this book:
The Island of Lost Maps; A True Cartographic Crime by Miles Harvey
Personal Log
Today’s blog blends the scientific with the personal. Maps are both of these things; a way to categorize and document our planet in a methodical, reasoned, repeatable, and scientific manner, and a way to personalize our planet to tell a story that we want to tell. Cool stuff to think about as we drive back and forth across our little polygon here in Cold Bay. It puts our work into perspective and creates both a sense of its importance and its relevance to describing a piece of our planet. Hmmmm, in my next lifetime maybe I should be a hydrographer……
