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How the History Aerial Photo Comparison is Put Together

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How the History Aerial Photo Comparison is Put Together

  1. Download imagery from USGS Earth Explorer (Free account needed to download; most interesting is to Single Aerial Photos) and USGS Historical Topographic Maps
  2. Use the QGIS Georeferencer to add control points and re-project the map.
  3. Export two matching area/scale images from QGIS showing the before and after
  4. Use the jQuery TwentyTwenty Plugin to provide the slider for your browser

The World Economy Runs on GPS. It Needs a Backup Plan

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The World Economy Runs on GPS. It Needs a Backup Plan

Most critical services, and financial markets, have backups—their own atomic clocks, perhaps, or connections to slightly less precise tools. But some of those backups depend on GPS timing, and might last only a few minutes. “GPS is the single point of failure for the entire modern economy,” says Representative John Garamendi, a California Democrat who’s been warning about the hazards for years as a member of the House committees on armed services and on transportation and infrastructure. “No cellphone, no ATM machine will work.”

Threats to the Tree of Life > Appalachian Voices

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Threats to the Tree of Life > Appalachian Voices

Tree of life: the iconic Celtic image likely depicts an oak tree, a food producer for animals and humans alike in protein-rich acorns. The tree of diversity: 450 to 600 species occur worldwide, depending on classification, as oaks easily hybridize. North America is an oak biodiversity hotspot with at least 220 species, the majority of which grow in Mexico. In Appalachia, about a dozen different oak species are found in various habitats.

These prominent trees have helped to shape culture, diet and ecosystems across the world, yet are facing significant threats to their ability to thrive. Today, oaks are struggling to regenerate, and diseases spreading in the West and Midwest could bring ecological devastation if they take root in Appalachia.