Search results
Results from the WOW.Com Content Network
This table shows the diagonal, horizontal, and vertical angles of view, in degrees, for lenses producing rectilinear images, when used with 36 mm × 24 mm format (that is, 135 film or full-frame 35 mm digital using width 36 mm, height 24 mm, and diagonal 43.3 mm for d in the formula above). [16]
(This is the angle α opposite the "rise" side of a triangle with a right angle between vertical rise and horizontal run.) as a percentage, the formula for which is which is equivalent to the tangent of the angle of inclination times 100. In Europe and the U.S. percentage "grade" is the most commonly used figure for describing slopes.
Pace [6] in minutes per kilometre or mile vs. slope angle resulting from Naismith's rule [7] for basal speeds of 5 and 4 km / h. [n 1]The original Naismith's rule from 1892 says that one should allow one hour per three miles on the map and an additional hour per 2000 feet of ascent.
For 6/6 = 1.0 acuity, the size of a letter on the Snellen chart or Landolt C chart is a visual angle of 5 arc minutes (1 arc min = 1/60 of a degree), which is a 43 point font at 20 feet. [10] By the design of a typical optotype (like a Snellen E or a Landolt C), the critical gap that needs to be resolved is 1/5 this value, i.e., 1 arc min.
Common aspect ratios used in film and display images. The common film aspect ratios used in cinemas are 1.85:1 and 2.39:1. [1] Two common videographic aspect ratios are 4:3 (1. 3:1), [a] the universal video format of the 20th century, and 16:9 (1. 7:1), universal for high-definition television and European digital television.
The modern anamorphic format has an aspect ratio of 2.39:1, meaning the (projected) picture's width is 2.39 times its height, (this is sometimes approximated to 2.4:1). The older Academy format of Anamorphic widescreen was a response to a shortcoming in the non-anamorphic spherical (a.k.a. "flat") widescreen format.
Until the late 19th century, first-angle projection was the norm in North America as well as Europe; [7] [8] but circa the 1890s, third-angle projection spread throughout the North American engineering and manufacturing communities to the point of becoming a widely followed convention, [7] [8] and it was an ASA standard by the 1950s. [8]
Coordinates were measured in grades on official French terrestrial ordnance charts from the French revolution well into the 20th century. 1 grade (or in modern symbology, 1 gon) = 0.9° or 0.01 right angle. One advantage of this measure is that the distance between latitude lines 0.01 gon apart at the equator is almost exactly 1 kilometre.