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Wide-area mapping of small-scale features in agricultural landscapes using airborne remote sensing.

O'Connell J, Bradter U, Benton TG - ISPRS J Photogramm Remote Sens (2015)

Bottom Line: A single object hierarchy with 4 class proportion of votes produced the best result (kappa 0.909).We found that ∼22% of hedgerows were within 200 m of margins with an area >183.31 m(2).The results from this analysis can form a key information source at the environmental and policy level in landscape optimisation for food production and ecosystem service sustainability.

View Article: PubMed Central - PubMed

Affiliation: School of Biology, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK.

ABSTRACT

Natural and semi-natural habitats in agricultural landscapes are likely to come under increasing pressure with the global population set to exceed 9 billion by 2050. These non-cropped habitats are primarily made up of trees, hedgerows and grassy margins and their amount, quality and spatial configuration can have strong implications for the delivery and sustainability of various ecosystem services. In this study high spatial resolution (0.5 m) colour infrared aerial photography (CIR) was used in object based image analysis for the classification of non-cropped habitat in a 10,029 ha area of southeast England. Three classification scenarios were devised using 4 and 9 class scenarios. The machine learning algorithm Random Forest (RF) was used to reduce the number of variables used for each classification scenario by 25.5 % ± 2.7%. Proportion of votes from the 4 class hierarchy was made available to the 9 class scenarios and where the highest ranked variables in all cases. This approach allowed for misclassified parent objects to be correctly classified at a lower level. A single object hierarchy with 4 class proportion of votes produced the best result (kappa 0.909). Validation of the optimum training sample size in RF showed no significant difference between mean internal out-of-bag error and external validation. As an example of the utility of this data, we assessed habitat suitability for a declining farmland bird, the yellowhammer (Emberiza citronella), which requires hedgerows associated with grassy margins. We found that ∼22% of hedgerows were within 200 m of margins with an area >183.31 m(2). The results from this analysis can form a key information source at the environmental and policy level in landscape optimisation for food production and ecosystem service sustainability.

No MeSH data available.


Related in: MedlinePlus

Box plots showing External (a) and Internal (OOB) (b) error as a function of sample size over 10 repetitions; where P10 is 10% sample size, P20 is 20% sample size etc. Whiskers represent the max and min, top and bottom of the box plot by 3rd and 1st quartile and the median by the centreline. The Y axis applies to both plots.
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f0020: Box plots showing External (a) and Internal (OOB) (b) error as a function of sample size over 10 repetitions; where P10 is 10% sample size, P20 is 20% sample size etc. Whiskers represent the max and min, top and bottom of the box plot by 3rd and 1st quartile and the median by the centreline. The Y axis applies to both plots.

Mentions: For training sample size the interquartile range within each sample size decreased with increasing sample size (Fig. 4).


Wide-area mapping of small-scale features in agricultural landscapes using airborne remote sensing.

O'Connell J, Bradter U, Benton TG - ISPRS J Photogramm Remote Sens (2015)

Box plots showing External (a) and Internal (OOB) (b) error as a function of sample size over 10 repetitions; where P10 is 10% sample size, P20 is 20% sample size etc. Whiskers represent the max and min, top and bottom of the box plot by 3rd and 1st quartile and the median by the centreline. The Y axis applies to both plots.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643754&req=5

f0020: Box plots showing External (a) and Internal (OOB) (b) error as a function of sample size over 10 repetitions; where P10 is 10% sample size, P20 is 20% sample size etc. Whiskers represent the max and min, top and bottom of the box plot by 3rd and 1st quartile and the median by the centreline. The Y axis applies to both plots.
Mentions: For training sample size the interquartile range within each sample size decreased with increasing sample size (Fig. 4).

Bottom Line: A single object hierarchy with 4 class proportion of votes produced the best result (kappa 0.909).We found that ∼22% of hedgerows were within 200 m of margins with an area >183.31 m(2).The results from this analysis can form a key information source at the environmental and policy level in landscape optimisation for food production and ecosystem service sustainability.

View Article: PubMed Central - PubMed

Affiliation: School of Biology, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK.

ABSTRACT

Natural and semi-natural habitats in agricultural landscapes are likely to come under increasing pressure with the global population set to exceed 9 billion by 2050. These non-cropped habitats are primarily made up of trees, hedgerows and grassy margins and their amount, quality and spatial configuration can have strong implications for the delivery and sustainability of various ecosystem services. In this study high spatial resolution (0.5 m) colour infrared aerial photography (CIR) was used in object based image analysis for the classification of non-cropped habitat in a 10,029 ha area of southeast England. Three classification scenarios were devised using 4 and 9 class scenarios. The machine learning algorithm Random Forest (RF) was used to reduce the number of variables used for each classification scenario by 25.5 % ± 2.7%. Proportion of votes from the 4 class hierarchy was made available to the 9 class scenarios and where the highest ranked variables in all cases. This approach allowed for misclassified parent objects to be correctly classified at a lower level. A single object hierarchy with 4 class proportion of votes produced the best result (kappa 0.909). Validation of the optimum training sample size in RF showed no significant difference between mean internal out-of-bag error and external validation. As an example of the utility of this data, we assessed habitat suitability for a declining farmland bird, the yellowhammer (Emberiza citronella), which requires hedgerows associated with grassy margins. We found that ∼22% of hedgerows were within 200 m of margins with an area >183.31 m(2). The results from this analysis can form a key information source at the environmental and policy level in landscape optimisation for food production and ecosystem service sustainability.

No MeSH data available.


Related in: MedlinePlus