Satellite imagery is sometimes used to manually digitize informal settlements. This approach is typically based on a priori definitions of deprivation, for example, defining deprived areas only as informal settlements with high built-up density, irregular layout pattern, small or no internal access roads, small buildings and lack of green spaces. The use of imagery to identify and delineate informal settlements does not depend on predefined areal units and thus may approximate actual informal settlement boundaries; however, the boundaries of more formalized deprived areas may be missed using this approach.

Such delineations may be performed by local or outside experts, and are labor intensive but can provide high-quality, detailed maps required by planners. Manual delineation is sometimes performed to minimum requirements, and if done by several interpreters, might be inconsistent. Furthermore, local experts might disagree in complex settings about the delineation of informal versus formal areas. Although local experts may be from the cities being mapped, delineation of informal settlements is generally performed without involvement of people living in those areas, ignoring local opinions, privacy, and geo-ethics. The degree to which human imagery interpretation reflects local context depends entirely upon who is doing the interpretation and delineation.