This is a project to visualize the triangulation network created for the Hayden Survey of Colorado. A map from this survey was placed on a digital elevation model and turned into a 3-D visualization.
One of the great surveyors in the American West is undoubtedly Ferdinand Vandeveer Hayden. A physician during the Civil war, he rose to be chief medical office of the Army of the Shenandoah. After the war he was appointed Geologist-in-charge of the United States Geological and Geographical Survey of the Territories.
Hayden spent the next few summers in the west surveying the areas around Yellowstone and the Grand Tetons. His annual reports caused excitement in Washington. They described stunning mountains, roaring rivers, boiling hot springs, geysers and exotic natural pools. When Hayden returned to Washington he fervently lobbied for the creation of Yellowstone National Park. It was established as the first national park in the United States by President Ulysses S. Grant in 1872.
In the post-war United States there was great fascination and ambition about Colorado. Horace Greeley, the journalist who is credited with the saying “Go West, young man” came to Colorado and inspired masses more to come. The 1860’s saw gold rushes near Pikes Peak and Central City. Denver was connected by two railroads and became a boom town for a decade.
However, Colorado was not properly mapped. Hayden’s new focus was in creating an atlas of the Rocky Mountains. He had created maps of the Yellowstone region but he wasn’t satisfied with their quality. He wanted to make maps of Colorado that would use all the latest scientific knowledge and techniques that could be accomplished in the 19th century.
The survey was painstaking work. A six mile baseline was established near Denver. It was crucial that this measurement was precise. The length was twice measured with steel tape. Temperature readings were taken every few minutes to account for any affects to the tape. When the six mile base line was established, rock cairns were set at either end.
From there the surveyors would use their transits to take readings on nearby mountain peaks. On the summits of those peaks cairns were placed as monuments to turn the transit upon. In this way a primary triangular network was created based on the six mile baseline.
An additional problem facing the surveyors was in getting the correct elevation. The method to do this before GPS was to use barometers. Barometers on there own aren’t very precise, so weather stations were set up around the state at locations with known elevations. When surveyors would reach peaks of unknown elevations they would take barometric readings. They would take many readings every day, sometimes over the period of several weeks. At the end of the season the barometer readings were compared to get a more precise elevation.
Over several summers the survey was divided into six or more groups working far apart from each other. The groups would have about a dozen men. They would include a topographer, geologist, cooks and other assistants. In addition a quartermaster would roam Colorado to bring food and supplies to the crews.
After returning to Washington Hayden and his lieutenants went about making the atlas. In 1877 the Hayden atlas was printed by Julius Bien and Company. It included many maps describing economic possibilities, drainages, geology and topography.
My main interest is the triangulation map from the atlas. This is a fascinating work: a visualization of the science of cartography. My goal was to take this flat map and overlay it onto a digital elevation model. Doing this gives it texture and shows the terrain that made this triangulation possible.
I started with a high-resolution copy of the map from the David Rumsey Map Collection. The map is very detailed and contains a coordinate grid along with all the peaks used in the network.
This is convenient because my next step is to georeference the map into QGIS software. Georeferencing is the process of taking an image of a map and assigning coordinates to points on the image. I started with the four corners of the map. This is easy because there are coordinates on the border of the map. I took the nearest grid intersection and assigned it the coordinate.
After that I georeferenced the peaks on the map. Places like Pikes Peak, Mount Peale, Mount Evans etc. have known coordinates that are easy to look up. I got coordinates on places distributed somewhat evenly around the map.
The next step is to stretch the image onto a model of the Earth. Fortunately QGIS can do this automatically once it’s georeferenced. It performs some heavy mathematical functions and puts the image on a map.
Now I can add a digital elevation model to the map. I downloaded the a 30 arc-second data set from the USGS (GMTED2010) and dropped that into QGIS. Now I have an elevation layer and an image layer.
Lastly I use a QGIS plugin called Qgis2threejs. This great plugin takes the map and turns it into a webpage that you can use in your browser. Then you can use your mouse to zoom around and rotate the image.
I exaggerated the size of the mountains to give it more definition. They aren’t real, but they are all scaled at the same level. Now you can zoom onto the map and get an idea of what the terrain looks like from a given location!
Suggested additional reading
Hayden’s Landscapes Revisited – An online work from the University of Colorado that locates the places where sketches of the survey were made and compares them with modern day views.
Great Surveys of the American West Richard A. Bartlett (1962)
Triangulation Map of Colorado – Hayden, F.V. (1881)
From the David Rumsey Map Collection