Sampling system for wheat (Triticum aestivum L)area estimation using digital Landsat MSS data and aerial photographs

A procedure to estimate wheat (Triticum aestivum L)area using sampling technique based on aerial photographs and digital LANDSAT MSS data was developed. Aerial photographs covering 720 km2 were visually analyzed. Computer classification of LANDSAT MSS data acquired on Sept. 2, 1979 was done using unsupervised and supervised algorithms and classification results were spatially filtered using a post-processing technique. To estimate wheat area, a regression approach was applied using different sample sizes and various sampling units (10, 20, 30, 40 and 60 km2). Based on four decision criteria proposed in this study, it was concluded that: (a)as the size of sampling unit decreased, the percentage of sampled area required to obtain similar estimation performance also decreased;(b)the lowest percentage of the area sampled for wheat estimation with relatively high precision and accuracy through regression estimation was 13,90 using 10km2 as the sampling unit; and (c)wheat area estimation using only aerial photographs was less precise and accurate than those obtained by regression estimation. / Pages: 336-346