Derived Characteristics

While many Geographic Characteristics are evaluated with data from other sources and stored, some are derived from other Geographic Characteristics. For example, building height may be calculated from the tangent of the site angle times the distance from the observer to the building. While formulae can be very complex, the technique called Reverse Polish Notation, described previously for derived Party Characteristics, is a way of representing them so that they can easily be evaluated.

Again, given a standard Formula, such as A=mx+y, this approach evaluates each variable in turn, from the outside in, until a value is obtained for the entire formula. In this example, you start by postulating m as a positive number. You ...

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