Faced with the complexity of the Earth's surface, the geomorphologist seeking to quantify its form is immediately forced to analyse it into more manageable components. He has two major strategies available. By defining specific landforms, he can abstract these from their surroundings to measure their size, shape and relation to each other. This approach, called specific geomorphometry, requires precise operational definitions (Sec. 2.5) and involves problems of landform delimitation and operator variance.