ABSTRACT
Irrigated areas have played a vital role in meeting the global food and fiber demands of the rapidly growing world population over the last five decades. Irrigated areas have expanded from the early 1940s with 95 million hectares (Mha) to 280 Mha at the beginning of the twenty-first century [1], following the “green revolution” in the 1960s. Irrigation remains a key plank in global and regional food-security strategies. Options to expand or enhance agricultural production require information on the extent, location, and type of irrigated crops in the world. Traditionally, this information is collected through laborious field surveys. The accuracy of the resulting maps largely depends on the sampling design and proportion of vegetated area surveyed. Furthermore, due to different levels of accuracy, often the results of these surveys cannot be used to compare spatial and temporal land use changes. With the emergence of satellite remote sensing, several attempts have been made to develop a consistent and rapid approach to map land cover and generate crop statistics [2] at a variety of scales.
