In a district plan or the Unitary Plan, there are zones for certain development activities. Examples are rural, commercial, or residential zones. There can also be overlays over these zones and precincts.
Overlays generally apply tighter controls over an area than the underlying zone does, although in some cases they can be more enabling. You can find overlays for your property on the Auckland Unitary Plan GeoMaps.
For example, the demolition of a building in the single house zone is a permitted activity; however, if the site is located within a special character overlay, the demolition of a building is a restricted discretionary activity and therefore requires a resource consent. Granting of the resource consent would be considered against the assessment criteria of the overlay.
When you view your property on the Auckland Unitary Plan GeoMaps you can look at the property zoning, and then select the layer you want to view from the list provided. All the different overlays will give you a better understanding of what might be allowed for your property.