How can I map component data without knowing where the components are?

As you know, each map unit represents an area that has up to three different kinds of soil, called components.

Components are each separate individual soils with individual properties and are grouped together for simplicity's sake when characterizing the map unit.

In the map unit shown here there are three components shown but in reality we don't know where the components are in a map unit. Thus when we map data which is gathered and stored at the component level (drainage class, for example) we must aggregate component-level data to the map unit. This aggregation can be done in a variety of ways; the most common are:

  • Selecting the dominant component and using it for the entire map unit
  • Finding the component with a limiting property and using it for the entire map unit
  • Calculating area-weighted values where each component contributes to the total based on it's percentage of the area of the map unit.

For different variables and different mapping purposes, different techniques are appropriate. Care is needed to make sure that the best method is being used