World Library  
Flag as Inappropriate
Email this Article

Aspect ratio

Article Id: WHEBN0000001021
Reproduction Date:

Title: Aspect ratio  
Author: World Heritage Encyclopedia
Language: English
Subject: Computer display standard, Comparison of Google Nexus tablets, HARMST, Digital photo frame, Spherical tokamak
Collection: Ratios
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Aspect ratio

The aspect ratio of a geometric shape is the ratio of its sizes in different dimensions. For example, the aspect ratio of a rectangle is the ratio of its longer side to its shorter side - the ratio of width to height,[1] when the rectangle is oriented as a "landscape".

The aspect ratio is expressed as two numbers separated by a colon (x:y). The values x and y do not represent actual width and height but, rather, the "relation" between width and height. As an example, 8:5, 16:10 and 1.6:1 are the same aspect ratio.

In objects of more than two dimensions, such as Hyperrectangles, the aspect ratio can still be defined as the ratio of the longest side to the shortest side.

Contents

  • Applications and uses 1
  • Aspect ratios of simple shapes 2
    • Rectangles 2.1
    • Ellipses 2.2
  • Aspect ratios of general shapes 3
  • Notations 4
  • See also 5
  • References 6
  • External links 7

Applications and uses

The term is most commonly used with reference to:

Aspect ratios of simple shapes

Rectangles

For a rectangle, the aspect ratio denotes the ratio of the width to the height of the rectangle. A square has the smallest possible aspect ratio of 1:1.

Examples:

Ellipses

For an ellipse, the aspect ratio denotes the ratio of the major axis to the minor axis. An ellipse with an aspect ratio of 1:1 is a circle.

Aspect ratios of general shapes

In geometry, there are several alternative definitions to aspect ratios of general compact sets in a d-dimensional space:[2]

  • The Diameter-Width Aspect Ratio (DWAR) of a compact set is the ratio of its diameter to its width. A circle has the minimal DWAR which is 1. A square has a DWAR of sqrt(2).
  • The Cube-Volume Aspect Ratio (CVAR) of a compact set is the d-th root of the ratio of the d-volume of the smallest enclosing axes-parallel d-cube, to the set's own d-volume. A square has the minimal CVAR which is 1. A circle has a CVAR of sqrt(2). An axis-parallel rectangle of width W and height H, where W>H, has a CVAR of sqrt(W^2/WH) = sqrt(W/H).

If the dimension d is fixed, then all reasonable definitions of aspect ratio are equivalent to within constant factors.

Notations

Aspect ratios are mathematically expressed as x:y (pronounced "x-to-y") and x×y (pronounced "x-by-y"), with the latter particularly used for pixel dimensions, such as 640×480.

Cinematographic aspect ratios are usually denoted as a (rounded) decimal multiple of width vs unit height, while photographic and videographic aspect ratios are usually defined and denoted by whole number ratios of width to height. In digital images there is a subtle distinction between the Display Aspect Ratio (the image as displayed) and the Storage Aspect Ratio (the ratio of pixel dimensions); see Distinctions.

See also

References

  1. ^
  2. ^

External links

  • Aspect ratio calculator, an interactive tool for calculating aspect ratio of objects
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.