Sampling Satellite Images for Area Estimates in a Large Region : Spatial Accuracy Assessment in Natural Resources and Environmental Sciences/ Second International Symposium : Spatial Accuracy Assesment in Natural Resources and Environmental Sciences/Second International Symposium

1996

S. 509-516

15 Lit. Ang.

Unselbständiges Werk

200047485

This paper describes two alternative methods (square sites and strips) to select a sample of sites for satellite image analysis giving priority to a particular type of area (intensive agricultural or forest) when no suitable stratification is available. Both methods are based on two-phase sampling. For square sites, a systematic sample is first drawn on the SPOT reference grid. Pre-selected sites are visually photo-interpreted for a rough estimation of the percentage of agricultural land or forest, that determines the sampling probability in the second phase. The alternative scheme, based on thin satellite image strips, seems to be more efficient than sampling square sites according to a simulation study based on ground survey data in Spain.