Choosing a survey sample when data on the population are limited: a method using Global Positioning Systems and aerial and satellite photographs

BackgroundVarious methods have been proposed for sampling when data on the population are limited. However, these methods are often biased. We propose a new method to draw a population sample using Global Positioning Systems and aerial or satellite photographs.ResultsWe randomly sampled Global Positioning System locations in designated areas. A circle was drawn around each location with radius representing 20 m. Buildings in the circle were …