Novel shape indices for vector landscape pattern analysis

ABSTRACT

The formation of an anisotropic landscape is influenced by natural and/or human processes, which can then be inferred on the basis of geometric indices. In this study, two minimal bounding rectangles in consideration of the principles of mechanics (i.e. minimal width bounding (MWB) box and moment bounding (MB) box) were introduced. Based on these boxes, four novel shape indices, namely MBLW (the length-to-width ratio of MB box), PAMBA (area ratio between patch and MB box), PPMBP (perimeter ratio between patch and MB box) and ODI (orientation difference index between MB and MWB boxes), were introduced to capture multiple aspects of landscape features including patch elongation, patch compactness, patch roughness and patch symmetry. Landscape pattern was, thus, quantified by considering both patch directionality and patch shape simultaneously, which is especially suitable for anisotropic landscape analysis. The effectiveness of the new indices were tested with real landscape data consisting of three kinds of saline soil patches (i.e. the elongated shaped slightly saline soil class, the circular or half-moon shaped moderately saline soil, and the large and complex severely saline soil patches). The resulting classification was found to be more accurate and robust than that based on traditional shape complexity indices.

KEYWORDS:

• Landscape metrics
• anisotropy
• moment box
• patch elongation
• patch symmetry

Acknowledgements

This research was supported by the European Union Erasmus Mundus Scholarship [grant number 2011-0155] and co-funded by the Lancaster University Research Fund. The authors are grateful to Professor Shanwen Qiu at Northeast Institute of Geography and Agro-ecology, Chinese Academy of Sciences, for his expertise on saline soil rule set development. The authors would also like to thank the two anonymous referees for their constructive comments on this article.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the European Union Erasmus Mundus Scholarship [grant number 2011-0155] and co-funded by the Lancaster University Research Fund.