. . , 2003
. 17, . 7, 647–672
Research Article
Increasing the spatial resolution of agricultural land cover maps using
a Hopfield neural network
A. J. TATEM
TALA Research Group, Department of Zoology, Oxford University,
South Parks Road, Oxford OX1 3PS, England, UK
e-mail: Andy.Tatem@zoology.oxford.ac.uk
H. G. LEWIS
Department of Aeronautical and Astronautical Engineering, University of
Southampton, Southampton SO17 1BJ, England, UK
P. M. ATKINSON
Department of Geography, University of Southampton, Southampton
SO17 1BJ, England, UK
and M. S. NIXON
Department of Electronics and Computer Science, University of Southampton,
Southampton SO17 1BJ, England, UK
(Received 12 July 2002; accepted 20 January 2003 )
Abstract. Land cover class composition of remotely sensed image pixels can be
estimated using soft classification techniques increasingly available in many GIS
packages. However, their output provides no indication of how such classes are
distributed spatially within the instantaneous field of view represented by the
pixel. Techniques that attempt to provide an improved spatial representation of
land cover have been developed, but not tested on the difficult task of mapping
from real satellite imagery. The authors investigated the use of a Hopfield neural
network technique to map the spatial distributions of classes reliably using
information of pixel composition determined from soft classification previously.
The approach involved designing the energy function to produce a ‘best guess’
prediction of the spatial distribution of class components in each pixel. In previous
studies, the authors described the application of the technique to target identifica-
tion, pattern prediction and land cover mapping at the sub-pixel scale, but only
for simulated imagery. We now show how the approach can be applied to Landsat
Thematic Mapper (TM) agriculture imagery to derive accurate estimates of land
cover and reduce the uncertainty inherent in such imagery. The technique was
applied to Landsat TM imagery of small-scale agriculture in Greece and large-
scale agriculture near Leicester, UK. The resultant maps provided an accurate
and improved representation of the land covers studied, with RMS errors for the
Landsat imagery of the order of 0.1 in the new fine resolution map recorded. The
results showed that the neural network represents a simple efficient tool for
International Journal of Geographical Information Science
ISSN 1365-8816 print/ISSN 1362-3087 online © 2003 Taylor & Francis Ltd
http://www.tandf.co.uk/journals
DOI: 10.1080/1365881031000135519