Halloween and TMA Air Photos

Last night, I had started mentally outlining a post about a wonderful new free resource that enables users to assess image quality based on calibration targets included in their images. But then I remembered that it’s Halloween, and I should instead pull together a post based on a spooky Halloween themed collection.

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While I came across a lot of great Halloween related material, including this collection from Wellcome Images, this 1903 film directed by Georges Méliès, and some charming children’s costumes via DPLA , what I decided to write about chilled me above all else. It is not a Medieval monster or menacing mummy, but rather a reminder of the very real Midwest winter to come. Specifically, it is the Antarctic Air Photography collection from the University of Minnesota.

Developed by the Polar Geospatial Center (PGC) at the University of Minnesota, this collection is comprised of more than 330,000 air photos, which were collected and scanned by the USGS EROS Data Center. The collection contains trimetrogon aerial photography, which is a method of taking three photos at one time: one vertical (in this collection, designated by a “V” in the filename), along with left and right obliques (at a 45° angle off nadir; designated by either “L” or “R”) taken along a single TMA flight line.

The easiest way to find Antarctic TMA photos, digitized flightline index maps, and approximate photo centers is through the PGC’s TMA Flightline Viewer, a web app that runs in your browser. The application allows users to browse and download Antarctic air photos digitally rather than having to search through rolls of film in the USGS archives. We even have camera calibration information here for those who need it.

Additionally, the PGC provides TMA flightline and photocenters data in two GIS formats: ESRI shapefiles (.shp) and Google Earth KMZ files. The files are separated by Antarctic region, such as Marie Byrd Land or Ross Island.

Users may also look up photos manually, rather than browsing by flightline or geographic region. A breakdown of USGS naming conventions is provided in order to help one navigate the data.

Have a happy and safe Halloween, and bundle up!

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