Population Estimation


Up-to-date and custom-tailored information products are provided on amount and spatial distribution of dwellings, dwelling density and internal structure of refugee/IDP camps and temporary settlements.
Monitoring is achieved by automated analysis of Earth observation (EO) data using object-based dwelling extraction, density calculation and camp growth analysis.

 

What for?

Population displacement due to armed conflicts, regional crisis or natural disasters often leads to temporary or semi-permanent refugee / IDP (internally displaced people) camps. The availability of optical very high spatial resolution (VHR) satellite images opens new possibilities to provide up-to date information on the camp situation for efficient and effective humanitarian aid. This includes understanding the population dynamics within a camp including the general growth of the camp (extent), camp structure, densification of camp sections, partly de- or reconstruction, etc. Remote sensing can help estimate the overall number of people present in a camp as well as other functions like population densities, camp management facilities etc.

Application domains: Logistics and site planning, shelter, camp coordination & camp management, health care, water and sanitation (watsan), nutrition.

 

 

    Data & Methods

 

Data: (multi-temporal) VHR satellite data; resolution ideally <= 0.5 m

Monitoring large-scale and highly dynamic refugee/IDP camps calls for automated imagery-based analysis. Using object-based image analysis (OBIA) we have developed algorithms for dwelling extraction over several years for various camps mainly located in Eastern Africa. Beginning with experimental stage research, the algorithms have been tested in real-time and benchmarking exercises and are now applied in pre-operational mode.

 

 

   

 

 

Products

 

 


Object-based dwelling extraction

Depending on roof material different dwelling types can be extracted (e.g. tents with white/blue tarpaulin, tukuls, dwellings with corrugated iron roof). A map is provided showing the extracted dwellings (polygons incl. size) together with the information of the amount of extracted dwellings.

   

Dwelling density

The dwelling density is calculated based on extracted dwellings and provides an easy-to-grasp overview on the spatial distribution of dwellings.

         
 

Camp structure

Depending on the distribution of dwelling types, a map can be provided showing the camp structure (e.g. prevailing areas with dwellings with tukuls as indicator for older camp areas and areas with predominantly tents as indicator for newly settled areas).

  

   
 Camp outline


Based on the dwelling density the camp outline is derived automatically. This information is especially required in rapidly expanding refugee/IDP camps where the extent can hardly be observed on the ground.

         
 


Camp evolution

Changes of single dwellings between two images from different times are aggregated
to regular units (e.g. hexagons) which indicate areas of dwelling increase or dwelling
decrease.

  

   


Spatial analysis

Enhancement of results from image classification by GIS analysis. E.g. aggregation of extracted dwellings to administrative units or calculation of distance maps for camp planning (how many dwellings are within a specific distance to boreholes, hospitals, latrines, etc.).