A linearised pixel-swapping method for mapping rural linear land cover features from fine spatial resolution remotely sensed imagery |
| |
Authors: | M.W. Thornton P.M. Atkinson D.A. Holland |
| |
Affiliation: | aSchool of Geography, University of Southampton, Highfield, Southampton SO17 1BJ, UK;bResearch and Innovation, C530, Ordnance Survey, Romsey Road, Maybush, Southampton SO16 4GU, UK |
| |
Abstract: | Accurate maps of rural linear land cover features, such as paths and hedgerows, would be useful to ecologists, conservation managers and land planning agencies. Such information might be used in a variety of applications (e.g., ecological, conservation and land management applications). Based on the phenomenon of spatial dependence, sub-pixel mapping techniques can be used to increase the spatial resolution of land cover maps produced from satellite sensor imagery and map such features with increased accuracy. Aerial photography with a spatial resolution of 0.25 m was acquired of the Christchurch area of Dorset, UK. The imagery was hard classified using a simple Mahalanobis distance classifier and the classification degraded to simulate land cover proportion images with spatial resolutions of 2.5 and 5 m. A simple pixel-swapping algorithm was then applied to each of the proportion images. Sub-pixels within pixels were swapped iteratively until the spatial correlation between neighbouring sub-pixels for the entire image was maximised. Visual inspection of the super-resolved output showed that prediction of the position and dimensions of hedgerows was comparable with the original imagery. The maps displayed an accuracy of 87%. To enhance the prediction of linear features within the super-resolved output, an anisotropic modelling component was added. The direction of the largest sums of proportions was calculated within a moving window at the pixel level. The orthogonal sum of proportions was used in estimating the anisotropy ratio. The direction and anisotropy ratio were then used to modify the pixel-swapping algorithm so as to increase the likelihood of creating linear features in the output map. The new linear pixel-swapping method led to an increase in the accuracy of mapping fine linear features of approximately 5% compared with the conventional pixel-swapping method. |
| |
Keywords: | Sub-pixel mapping Super-resolution Feature extraction Land cover mapping Sub-pixel Classification |
本文献已被 ScienceDirect 等数据库收录! |
|