The Davison Relationship Chart is a horoscope for the midpoint of two people's birth times.

There are the following variants of the Davison Relationship Chart (DRC):

• "Davison Relationship Chart, uncorrected": The chart is calculated for the averaged geographical longitude and the averaged geographical latitude of both natal charts.
  Latitude (DRC) = (latitude chart 1 + latitude chart 2) / 2
  Longitude (DRC) = (longitude chart 1 + longitude chart 2) /2.
• "Davision Relationship Chart, corrected": The chart is calculated for the averaged geographical longitude and the averaged geographical latitude. However, the time is corrected in such a way that the resulting MC is the same as the composite MC of both charts. This is the classical calculation method of the Davison Relationship Chart. (see also "Composite Chart")
• "Davison Relationship Chart, reference place": The chart is calculated for a certain reference place (e.g. the common place of residence of the people concerned). The reference place can be set in the "Extended Chart Selection" under "Default settings".
• "Davison Relationship Chart, spherical midpoint": The chart is calculated for the shortest distance between both birth places, the so-called "spherical midpoint". If both birth places are a long way apart, e.g. in Hawaii and in Switzerland, the resulting spherical midpoint can lie close to the geographical north pole. This method therefore often leads to problems with the house system.