Abstract
Upland vegetation represents an important resource that requires frequent monitoring. However, the heterogeneous nature of upland vegetation and lack of ground data require classification techniques that have a high degree of generalization ability. This study investigates the use of artificial neural networks as a means of mapping upland vegetation from remotely sensed data. First, the optimum size of support to map upland vegetation was estimated as being less than 4 m, which suggested that soft classification techniques and high spatial resolution IKONOS imagery were required. The use of high spatial resolution imagery for regional‐scale areas has introduced new challenges to the remote sensing community, such as using limited ground data and mapping land‐cover dynamics and variation over large areas. This work then investigated the utility of artificial neural networks (ANN) for regional‐scale upland vegetation from IKONOS imagery using limited ground data and to map unseen data from remote geographical locations. A Multiple Layer Perceptron was trained with pixels from an IKONOS image using early stopping; however, despite high classification accuracies when calculated for pixels from an area where training pixels were extracted, the networks did not produce high accuracies when applied to unseen data from a remote area.
Acknowledgements
This paper is an extended version of a paper presented at the Annual Conference of the Remote Sensing & Photogrammetry Society (Nottingham, UK) in September 2003. The authors wish to thank the Ministry of Defence and the Northumberland National Park Authority, in particular Gillian Thompson, for their financial support and assistance in the field. Additionally the authors are grateful to Martin Robertson for field assistance and Peter Andras for advice on ANNs. The authors also wish to thank the two anonymous referees for their valuable comments and suggestions.