Methods for determining the uncertainty of population estimates derived from satellite imagery and limited survey data: a case study of Bo city, Sierra Leone

Roger Hillson; Joel D Alejandre; Kathryn H Jacobsen; Rashid Ansumana; Alfred S Bockarie; Umaru Bangura; Joseph M Lamin; Anthony P Malanoski; David A Stenger

doi:10.1371/journal.pone.0112241

Methods for determining the uncertainty of population estimates derived from satellite imagery and limited survey data: a case study of Bo city, Sierra Leone

PLoS One. 2014 Nov 14;9(11):e112241. doi: 10.1371/journal.pone.0112241. eCollection 2014.

Authors

Roger Hillson¹, Joel D Alejandre¹, Kathryn H Jacobsen², Rashid Ansumana³, Alfred S Bockarie³, Umaru Bangura⁴, Joseph M Lamin⁴, Anthony P Malanoski⁵, David A Stenger⁵

Affiliations

¹ Information Technology Division, Naval Research Laboratory, Washington, District of Columbia, United States of America.
² Department of Global and Community Health, George Mason University, Fairfax, Virginia, United States of America.
³ Njala University, Bo, Sierra Leone; Mercy Hospital Research Laboratory, Bo, Sierra Leone.
⁴ Mercy Hospital Research Laboratory, Bo, Sierra Leone.
⁵ Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, District of Columbia, United States of America.

Abstract

This study demonstrates the use of bootstrap methods to estimate the total population of urban and periurban areas using satellite imagery and limited survey data. We conducted complete household surveys in 20 neighborhoods in the city of Bo, Sierra Leone, which collectively were home to 25,954 persons living in 1,979 residential structures. For five of those twenty sections, we quantized the rooftop areas of structures extracted from satellite images. We used bootstrap statistical methods to estimate the total population of the pooled sections, including the associated uncertainty intervals, as a function of sample size. Evaluations based either on rooftop area per person or on the mean number of occupants per residence both converged on the true population size. We demonstrate with this simulation that demographic surveys of a relatively small proportion of residences can provide a foundation for accurately estimating the total population in conjunction with aerial photographs.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Computer Simulation
Databases as Topic
Demography*
Geography
Humans
Population Density*
Residence Characteristics
Sample Size
Satellite Imagery / methods*
Sierra Leone
Uncertainty*

Grants and funding

This work was funded by the Defense Threat Reduction Agency, Joint Science and Technology Office via contract to the United States Naval Research Laboratory. There is no past, present or future Intellectual Property associated with the work described in the paper, and none of the authors have any financial interests or conflicts in the outcome of the study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.