Mapping Urban Tree Cover Changes Using Object-Based Convolution Neural Network (OB-CNN)
Urban trees provide social, economic, environmental and ecosystem services benefits that improve the liveability of cities and contribute to individual and community wellbeing. There is thus a need for effective mapping, monitoring and maintenance of urban trees. Remote sensing technologies can effe...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-09-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/12/18/3017 |
| _version_ | 1797553507775021056 |
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| author | Shirisa Timilsina Jagannath Aryal Jamie B. Kirkpatrick |
| author_facet | Shirisa Timilsina Jagannath Aryal Jamie B. Kirkpatrick |
| author_sort | Shirisa Timilsina |
| collection | DOAJ |
| description | Urban trees provide social, economic, environmental and ecosystem services benefits that improve the liveability of cities and contribute to individual and community wellbeing. There is thus a need for effective mapping, monitoring and maintenance of urban trees. Remote sensing technologies can effectively map and monitor urban tree coverage and changes over time as an efficient and low-cost alternative to field-based measurements, which are time consuming and costly. Automatic extraction of urban land cover features with high accuracy is a challenging task, and it demands object based artificial intelligence workflows for efficiency and thematic accuracy. The aim of this research is to effectively map urban tree cover changes and model the relationship of such changes with socioeconomic variables. The object-based convolutional neural network (CNN) method is illustrated by mapping urban tree cover changes between 2005 and 2015/16 using satellite, Google Earth imageries and Light Detection and Ranging (LiDAR) datasets. The training sample for CNN model was generated by Object Based Image Analysis (OBIA) using thresholds in a Canopy Height Model (CHM) and the Normalised Difference Vegetation Index (NDVI). The tree heatmap produced from the CNN model was further refined using OBIA. Tree cover loss, gain and persistence was extracted, and multiple regression analysis was applied to model the relationship with socioeconomic variables. The overall accuracy and kappa coefficient of tree cover extraction was 96% and 0.77 for 2005 images and 98% and 0.93 for 2015/16 images, indicating that the object-based CNN technique can be effectively implemented for urban tree coverage mapping and monitoring. There was a decline in tree coverage in all suburbs. Mean parcel size and median household income were significantly related to tree cover loss (R<sup>2</sup> = 58.5%). Tree cover gain and persistence had positive relationship with tertiary education, parcel size and ownership change (gain: R<sup>2</sup> = 67.8% and persistence: R<sup>2</sup> = 75.3%). The research findings demonstrated that remote sensing data with intelligent processing can contribute to the development of policy input for management of tree coverage in cities. |
| first_indexed | 2024-03-10T16:17:26Z |
| format | Article |
| id | doaj.art-44f27f6970ef430a9c9796317c3ae843 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T16:17:26Z |
| publishDate | 2020-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-44f27f6970ef430a9c9796317c3ae8432023-11-20T13:55:33ZengMDPI AGRemote Sensing2072-42922020-09-011218301710.3390/rs12183017Mapping Urban Tree Cover Changes Using Object-Based Convolution Neural Network (OB-CNN)Shirisa Timilsina0Jagannath Aryal1Jamie B. Kirkpatrick2School of Technology, Environments and Design, Discipline of Geography and Spatial Sciences, University of Tasmania, Hobart, Tasmania 7001, AustraliaSchool of Technology, Environments and Design, Discipline of Geography and Spatial Sciences, University of Tasmania, Hobart, Tasmania 7001, AustraliaSchool of Technology, Environments and Design, Discipline of Geography and Spatial Sciences, University of Tasmania, Hobart, Tasmania 7001, AustraliaUrban trees provide social, economic, environmental and ecosystem services benefits that improve the liveability of cities and contribute to individual and community wellbeing. There is thus a need for effective mapping, monitoring and maintenance of urban trees. Remote sensing technologies can effectively map and monitor urban tree coverage and changes over time as an efficient and low-cost alternative to field-based measurements, which are time consuming and costly. Automatic extraction of urban land cover features with high accuracy is a challenging task, and it demands object based artificial intelligence workflows for efficiency and thematic accuracy. The aim of this research is to effectively map urban tree cover changes and model the relationship of such changes with socioeconomic variables. The object-based convolutional neural network (CNN) method is illustrated by mapping urban tree cover changes between 2005 and 2015/16 using satellite, Google Earth imageries and Light Detection and Ranging (LiDAR) datasets. The training sample for CNN model was generated by Object Based Image Analysis (OBIA) using thresholds in a Canopy Height Model (CHM) and the Normalised Difference Vegetation Index (NDVI). The tree heatmap produced from the CNN model was further refined using OBIA. Tree cover loss, gain and persistence was extracted, and multiple regression analysis was applied to model the relationship with socioeconomic variables. The overall accuracy and kappa coefficient of tree cover extraction was 96% and 0.77 for 2005 images and 98% and 0.93 for 2015/16 images, indicating that the object-based CNN technique can be effectively implemented for urban tree coverage mapping and monitoring. There was a decline in tree coverage in all suburbs. Mean parcel size and median household income were significantly related to tree cover loss (R<sup>2</sup> = 58.5%). Tree cover gain and persistence had positive relationship with tertiary education, parcel size and ownership change (gain: R<sup>2</sup> = 67.8% and persistence: R<sup>2</sup> = 75.3%). The research findings demonstrated that remote sensing data with intelligent processing can contribute to the development of policy input for management of tree coverage in cities.https://www.mdpi.com/2072-4292/12/18/3017convolution neural networks (CNNs)deep learningGEOBIAobject-based CNNurban tree mappingsocioeconomic predictor variables |
| spellingShingle | Shirisa Timilsina Jagannath Aryal Jamie B. Kirkpatrick Mapping Urban Tree Cover Changes Using Object-Based Convolution Neural Network (OB-CNN) Remote Sensing convolution neural networks (CNNs) deep learning GEOBIA object-based CNN urban tree mapping socioeconomic predictor variables |
| title | Mapping Urban Tree Cover Changes Using Object-Based Convolution Neural Network (OB-CNN) |
| title_full | Mapping Urban Tree Cover Changes Using Object-Based Convolution Neural Network (OB-CNN) |
| title_fullStr | Mapping Urban Tree Cover Changes Using Object-Based Convolution Neural Network (OB-CNN) |
| title_full_unstemmed | Mapping Urban Tree Cover Changes Using Object-Based Convolution Neural Network (OB-CNN) |
| title_short | Mapping Urban Tree Cover Changes Using Object-Based Convolution Neural Network (OB-CNN) |
| title_sort | mapping urban tree cover changes using object based convolution neural network ob cnn |
| topic | convolution neural networks (CNNs) deep learning GEOBIA object-based CNN urban tree mapping socioeconomic predictor variables |
| url | https://www.mdpi.com/2072-4292/12/18/3017 |
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