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  2. Geographical distance - Wikipedia

    en.wikipedia.org/wiki/Geographical_distance

    Geographical distance or geodetic distance is the distance measured along the surface of the Earth, or the shortest arch length. The formulae in this article calculate distances between points which are defined by geographical coordinates in terms of latitude and longitude. This distance is an element in solving the second (inverse) geodetic ...

  3. Heat equation - Wikipedia

    en.wikipedia.org/wiki/Heat_equation

    The temperature approaches a linear function because that is the stable solution of the equation: wherever temperature has a nonzero second spatial derivative, the time derivative is nonzero as well. The heat equation implies that peaks ( local maxima ) of u {\displaystyle u} will be gradually eroded down, while depressions ( local minima ...

  4. Vincenty's formulae - Wikipedia

    en.wikipedia.org/wiki/Vincenty's_formulae

    Vincenty's formulae are two related iterative methods used in geodesy to calculate the distance between two points on the surface of a spheroid, developed by Thaddeus Vincenty (1975a). They are based on the assumption that the figure of the Earth is an oblate spheroid, and hence are more accurate than methods that assume a spherical Earth, such ...

  5. Temperature gradient - Wikipedia

    en.wikipedia.org/wiki/Temperature_gradient

    A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location. The temperature spatial gradient is a vector quantity with dimension of temperature difference per unit length. The SI unit is kelvin per meter (K/m).

  6. Gradient - Wikipedia

    en.wikipedia.org/wiki/Gradient

    Consider a room where the temperature is given by a scalar field, T, so at each point (x, y, z) the temperature is T(x, y, z), independent of time. At each point in the room, the gradient of T at that point will show the direction in which the temperature rises most quickly, moving away from (x, y, z). The magnitude of the gradient will ...

  7. Thermal conduction - Wikipedia

    en.wikipedia.org/wiki/Thermal_conduction

    A nomogram has a relative temperature as the y coordinate and the Fourier number, which is calculated by =. The Biot number increases as the Fourier number decreases. There are five steps to determine a temperature profile in terms of time. Calculate the Biot number

  8. Sunrise equation - Wikipedia

    en.wikipedia.org/wiki/Sunrise_equation

    A contour plot of the hours of daylight as a function of latitude and day of the year, using the most accurate models described in this article. It can be seen that the area of constant day and constant night reach up to the polar circles (here labeled "Anta. c." and "Arct. c."), which is a consequence of the earth's inclination.

  9. Earth-centered, Earth-fixed coordinate system - Wikipedia

    en.wikipedia.org/wiki/Earth-centered,_Earth...

    The reverse conversion is harder: given X-Y-Z can immediately get longitude, but no closed formula for latitude and height exists. See "Geodetic system." Using Bowring's formula in 1976 Survey Review the first iteration gives latitude correct within 10-11 degree as long as the point is within 10,000 meters above or 5,000 meters below the ellipsoid.