November 17, 2015

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LTOs Are Here!

Originally published November 16, 2004


LTOs Are Here!

Once again, quietly and without fanfare, the Lunar & Planetary Institute has delivered a magnificent collection of rare lunar maps for our daily use. The Lunar Topographic Orthophotomaps - the absolutely best lunar maps ever map - are 1:250,000 scale Apollo Metric photos overprinted with accurate topographic contours at 100 m vertical intervals. LPI has released digitized versions of 215 LTOs at 4 resolutions: a browse image; a 72 dpi, 2.7 MB image; a 150 dpi, 10 MB image; and a high res image that is so big you have to request LPI puts it on a ftp server for you. I browsed through many images (and already downloaded 3 of the 150 dpi ones - I need that res to read all the contours) to remind myself of what they show. At the top left corner of the index map shown above is a small piece of 41-A4 map of the Beer and Feuille area southwest of Archimedes that gives a degraded view of the large scale and contour density. As the coverage map shows, only the areas under the Apollo 15, 16 and 17 flight paths had stereo coverage allowing topography to be derived by photogrammetry. But this area includes many interesting features, including the rugged dome Cauchy Tau, which is seen to be 342 m high, quite a bit taller than the previous best estimate of 149 m derived from the less accurate photometric method. Most of these LTO maps were published in 1974, so 30 years later, enjoy them and thank LPI for their tremendous effort in digitizing and placing these treasures online!

Chuck Wood

Yesterday's LPOD: A Busier Longo

Tomorrow's LPOD: A Glorious Serpentine Ridge

Author & Editor:
Charles A. Wood



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