The centroid is the centre of a digital bounded area, for example a Collection District (CD). This point is assigned a set of latitude and longitude coordinates.
In some cases, such as a crescent-shaped area, the centroid may lie outside the limits of the area.
The centroid enables Census data to be reproduced for any aggregation of CDs falling within any radius of a defined point. For example, a client may require data for a television viewing area. This may require the identification of all CDs with a centroid within a twenty kilometre radius of a particular CD. Some thematic maps containing Census data attach symbols to centroids for display purposes.
See Collection District (CD), Digital base map data, Digital boundaries.