Traditional astrologers use a weighting system to ascertain the value (relative strengths) of a given planet in a chart. This system is used in order to determine the overall chart rulership, along with the discovery of any almuten or important factors that clarify the issues in a delineation.
To use this table, first check the position in the chart of each planet in order to establish its dignities and debilities. Essential Dignities can be ascertained from Ptolemy's Table of Essential Dignities and a simple analysis of the chart in question will provide the Accidental Dignities. Then list the numerical values of the planet according to this table, adding the value of its dignities and subtracting the value of its debilities. This will give you a final number, which is its value in the chart concerned. Only the visible planets, Saturn, Jupiter, Mars, Sun, Venus, Mercury and Moon, along with the Moon's nodes, have traditional dignity. The outer planets, Uranus, Neptune, Pluto, and asteroids, etc., have no traditional value – and though they may be allowed to have some influence, they do not fit into the symbolic structure of the traditional astrological system.
Bear in mind that Accidental Dignity is more significant than Essential Dignity in the interpretation of a chart, although both are important. The unfortunate influence of a malefic is usually diminished when in dignity, whilst the fortunate influence of a benefic is increased.