[Qgis-user] Re: distance between points in a table

[Kaimbridge M. GoldChild]

Back on 22.05.2012 20:27, Benoit wrote:

  > Notes:
  >
  >  - The value of 6372.8 km is as given by Wikipedia
  > [0] while Spatialite uses a radius of 6371.01 km.

Right, “6371.01” is the authalic radius based on/extracted
from surface area, while “6372.8” is an approximation of the
radius of the average circumference (i.e., the average
“great-elliptic” or “great-circle radius”), where the boundaries
are the meridian (≈ 6367.45 km) and the equator (≈ 6378.14 km).
See “Ellipsoidal quadratic mean radius”:

           http://wiki.gis.com/wiki/index.php/Ellipsoidal_quadratic_mean_radius

       ~Kaimbridge~

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