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

Hillson R, Alejandre JD, Jacobsen KH, Ansumana R, Bockarie AS, Bangura U, Lamin JM, Malanoski AP, Stenger DA - PLoS ONE (2014)

Bottom Line: For five of those twenty sections, we quantized the rooftop areas of structures extracted from satellite images.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.

View Article: PubMed Central - PubMed

Affiliation: Information Technology Division, 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.

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A comparison of occupancy-based and rooftop area-based bootstrap population estimators.(A) Occupancy-based population estimations and (B) rooftop area-based population estimations with 0.50 CIs (blue) and 0.95 CIs (red). There are 464 residences (DS02) and 2,000 bootstrap replications per sample. The confidence intervals (CIs) were calculated using bootstrap percentiles.
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pone-0112241-g005: A comparison of occupancy-based and rooftop area-based bootstrap population estimators.(A) Occupancy-based population estimations and (B) rooftop area-based population estimations with 0.50 CIs (blue) and 0.95 CIs (red). There are 464 residences (DS02) and 2,000 bootstrap replications per sample. The confidence intervals (CIs) were calculated using bootstrap percentiles.

Mentions: SIM02 and SIM03. The occupancy-based and rooftop-area based sequences of sample size simulations for dataset DS02 ( = 462) are compared in Figure 5. Both estimators converge properly. The uncertainty of the occupancy-based estimator is about 20% less than for the rooftop-based estimator for both the 0.95 and 0.50 confidence intervals. For a given sample size and confidence interval, the corresponding confidence interval is defined as the difference between the upper and lower confidence limits. For each estimator, and for each of the two confidence intervals, 14 confidence intervals were calculated. A two-tailed paired t test between the paired differences was statistically significant for both confidence levels ().


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

Hillson R, Alejandre JD, Jacobsen KH, Ansumana R, Bockarie AS, Bangura U, Lamin JM, Malanoski AP, Stenger DA - PLoS ONE (2014)

A comparison of occupancy-based and rooftop area-based bootstrap population estimators.(A) Occupancy-based population estimations and (B) rooftop area-based population estimations with 0.50 CIs (blue) and 0.95 CIs (red). There are 464 residences (DS02) and 2,000 bootstrap replications per sample. The confidence intervals (CIs) were calculated using bootstrap percentiles.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4232376&req=5

pone-0112241-g005: A comparison of occupancy-based and rooftop area-based bootstrap population estimators.(A) Occupancy-based population estimations and (B) rooftop area-based population estimations with 0.50 CIs (blue) and 0.95 CIs (red). There are 464 residences (DS02) and 2,000 bootstrap replications per sample. The confidence intervals (CIs) were calculated using bootstrap percentiles.
Mentions: SIM02 and SIM03. The occupancy-based and rooftop-area based sequences of sample size simulations for dataset DS02 ( = 462) are compared in Figure 5. Both estimators converge properly. The uncertainty of the occupancy-based estimator is about 20% less than for the rooftop-based estimator for both the 0.95 and 0.50 confidence intervals. For a given sample size and confidence interval, the corresponding confidence interval is defined as the difference between the upper and lower confidence limits. For each estimator, and for each of the two confidence intervals, 14 confidence intervals were calculated. A two-tailed paired t test between the paired differences was statistically significant for both confidence levels ().

Bottom Line: For five of those twenty sections, we quantized the rooftop areas of structures extracted from satellite images.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.

View Article: PubMed Central - PubMed

Affiliation: Information Technology Division, 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.

Show MeSH