Speaking of historical satellite imagery, Bill Morris went digging for satellite imagery of what preceded Manicouagan Reservoir before it was created in the 1960s by Quebec’s massive hydro dam projects. But since Landsat first launched in 1973, after the dam was completed, what imagery was there? Answer: CIA spy satellite imagery from 1965—when satellites took pictures on film that was then sent back to Earth—that was declassified in 1996. Read more.
Category: Surveying
A Look Back at the SRTM
Last month NASA Earth Observatory ran a two-part series about the Shuttle Radar Topography Mission, which produced a high-resolution digital elevation model of the Earth based on radar data collected by the shuttle Endeavour in 2000. The first part looks at how Endeavour gathered the data, the second part at how it’s been used.
Nearly a quarter century after the mission to map the world, the SRTM’s data still yields results. Just this year, it aided in wildfire forecasting for Iran’s Zagros Mountains, tracking soil erosion in South Africa, assessing flood risk on the coast of Brazil, and even determining how the locations of power-generating wind turbines affect real estate values. Tens of thousands of research papers are published every year that rely on SRTM maps for these and other environmental, economic, agricultural, and public safety studies.
Mapping Without a Licence
An odd story out of California, reported on by Vice’s Chloe Xiang, from earlier this month. Ryan Crownholm’s website, MySitePlan.com, sells residential and commercial site plans. California’s Board for Professional Engineers, Land Surveyors, and Geologists has fined him $1,000 for practising land surveying without a licence and ordered him to shut down the site. He’s fighting the citation in court with the assistance of the libertarian Institute for Justice: see their page on the complaint. Their argument is that California surveying laws are vague enough that a literal interpretation would make any map drawn in California, no matter how informal or non-authoritative, illegal.
It’s unlikely to say the least that the Board intends to ban Google Maps or every California-based instance of GIS. This is an edge case. Crownholm’s defence turns on his drawings being “non-authoritative” and a disclaimer that these are not legal surveys. The Board apparently thinks that’s insufficient. A spot of litigation seems required to clarify things.
The Tellurometer, with a Girl to Help
To start off your weekend, here’s a 1961 clip from British Pathé depicting the surveying and mapmaking technologies of the era. [Massimo]
The Impact of NOAA’s Height Modernization Program
Last month the New York Times covered a subject that you’d expect to be too technical for the general reader: NOAA’s efforts to recalibrate elevation data as part of its update to the National Spatial Reference System, expected in 2022 or 2023. The height modernization program corrects local elevation data—which was last updated in 1988—by using GPS and gravity mapping. The Times article looks at the real-world implications of this effort, which will have the greatest impact the further west and north you go (see map above), from bragging rights about mountain elevation to whether your community is in a floodplain. [MAPS-L]
Previously: NATRF2022 Datum Coming to North America in 2022.
Inō Tadataka, Surveyor of Japan
Britain had the Ordnance Survey, France the Cassini family. Japan had Inō Tadataka (伊能 忠敬, 1745-1818), who over a series of expeditions in the early 19th century conducted a systematic survey of Japan using modern techniques. Writing for Nippon.com, Inō’s biographer, Hoshino Yoshihisa, writes a long introduction to Inō’s life and work that is well worth the read. [Tony Campbell]
For more on the history of Japanese cartography, see Cartographic Japan, a collection of academic essays edited by Kären Wigen, Sugimoto Fumiko and Cary Karacas that was published by the University of Chicago Press in 2016.
The Secret Mission to Seize German Map Data in World War II
Greg Miller’s crackerjack story in the November 2019 issue of Smithsonian magazine is about the quest to capture German geodetic data—and German geographers—during the dying days of the Second World War. Said data was a strategically critical treasure trove, of immense interest to the U.S. War Department, and the team led by Floyd W. Hough was in a race to find it before it was destroyed, carried away by the enemy, or fell into Soviet hands.
Little is publicly known about the true scope of the information that Hough and his team captured, or the ingenuity they displayed in securing it, because their mission was conducted in secret, and the technical material they seized circulated only among military intelligence experts and academics. But it was a vast scientific treasure—likely the largest cache of geographic data the United States ever obtained from an enemy power in wartime.
The data seized by Hough’s team went on to form the basis of the ED50 geodetic datum, which in turn led to the Universal Tranverse Mercator system.
Monmonier’s Latest: Connections and Content
Mark Monmonier’s latest book, Connections and Content: Reflections on Networks and the History of Cartography (Esri Press, August ebook/September paperback) is about “the relationships between networks and maps”—what does that mean? Apparently: triangulation networks, postal networks, telegraph networks survey networks, astronomical observations and other underlying data. Steven Seegel interviews Monmonier about the book for the New Books in Geography podcast. [Amazon]
Antarctica at Eight-Metre Resolution
The Reference Elevation Model of Antarctica is a terrain map of nearly the entire continent at eight-metre resolution, assembled from observations from polar-orbiting satellites (mostly in 2015 and 2016). Version 1 covers 98 percent of Antarctica, and observations are ongoing. Notably, each grid point is timestamped, which will allow researchers to track changes over time (useful when your continent is melting). Raw data is available for download, as are map posters; the data is also available via web apps. [Geographical]
The BBC on the Ordnance Survey
Speaking of the Ordnance Survey, here’s a potted history of the OS from the BBC’s Bethan Bell. The definitive history, of course, is Rachel Hewitt’s Map of a Nation (2010), which I reviewed in 2012, but it only covers the first century or so. Bell’s piece is full of factoids—scattershot, random access—from both the 19th and 20th centuries. [A-Z Maps]
Mapping Denali in Detail
Matt Nolan and his family have created a topographic map of Denali, the highest peak in North America, using a form of stereo photogrammetry Nolan calls fodar: they repeatedly overflew the peak in a small airplane and took photos of the terrain below with a digital SLR. The end result is a 20-cm terrain model they’re touting as the best ever of the mountain, far more detailed than previous maps. Nolan outlines their endeavour in two blog posts: one focusing on the personal, the other on the technical; the latter also has lots of terrain models and comparisons with USGS data.
He’s also running a crowdfunding campaign to underwrite the costs of additional map flights. [WMS]
The Coastline Paradox
This short video does a good job explaining the coastline paradox, which basically results from coastlines being fractal, and the length of a coastline can vary quite a lot depending on the method you use to measure it. More at Mental Floss. [WMS]
LIDAR Mapping Reveals a Far Greater Mayan Civilization
A 2016 aerial survey of ten sites in Guatemala’s Maya Biosphere Reserve used LIDAR to digitally remove the tree canopy from the landscape, revealing, National Geographic reports, “the ruins of a sprawling pre-Columbian civilization that was far more complex and interconnected than most Maya specialists had supposed”—and one that likely supported a much higher population than previously thought. The survey and its findings are the subject of a documentary special premiering tomorrow on the National Geographic channel. More coverage: CBC News, The New York Times, The Verge, The Washington Post.
Early Radar Maps of Antarctica Digitized
Nature: “Glaciologists will soon have a treasure trove of data for exploring how Antarctica’s underbelly has changed over nearly half a century. An international team of researchers has scanned and digitized 2 million records from pioneering aeroplane radar expeditions that criss-crossed the frozen continent in the 1960s and 1970s. […] The digitized data extend the record of changes at the bottom of the ice sheet, such as the formation of channels as Antarctica’s ice flows, by more than two decades.” (Modern radar mapping of Antarctica apparently only began in the 1990s.) [WMS]
British Antarctic Survey Remeasures Mount Hope
This BBC News article leads with a reasonably interesting geographic fact: that Mount Hope, on the Antarctic Peninsula, has been remeasured at 3,239 metres, making it the tallest mountain in territory claimed by the United Kingdom. (Its location is also claimed by Argentina and Chile.) But it’s really about the British Antarctic Survey, who are using stereographic satellite data to create more accurate maps of Antarctica’s mountains for pilots operating on the continent. BAS press release. [Kenneth Field]