Geometry, Alignment & Mapping at Tulum, Mexico
Hugh Harleston's illustration of the alignments at Tulum, along with a photo of the building, showing a perforated roof "comb," or windows, which would have allowed tracking of the Sun's position using the shadows cast by the comb.
Facing away from the structure with the sun-tracking windows.
Compare the intact roof comb structure at Yaxchilan, Mexico. darlene.applegate(at)wku.edu
Do aerial photos of Tulum show that it is built in the pattern of the constellation "the big dipper?" The Gizeh pyramids are built in the pattern of Orion's belt, the Notre Dame cathedrals in the pattern of Virgo, and certain features in Somerset in the shape of Canus Major.
Alignment of Tulum & Coba? Well, since Coba was a Classic Era city and Tulum most definitely a late Post-classic city, their alignment is highly speculative, particularly since Coba made a point of connecting their allied cities with major sacbeob.
Astronomical alignment of Maya architecture? highly likely. A careful reading of David Freidel's and Linda Schele's "Maya Cosmos" is mandatory. Also the works of Tony Aveni on Mesoamerican archaeoastronomy.