the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 24 Mar 2025
Introducing a Learning Tool (QSVI): A QGIS Plugin for Computing Vegetation, Chlorophyll, and Thermal Indices with Remote Sensing Images
Abstract. Recent advances in remote sensing technology have increased the demand for software that supports educational and research activities. However, commercial software often comes with high costs and complex interfaces, presenting challenges for users. In contrast, open-source software offers a more accessible and cost-effective solution, making it increasingly popular for remote sensing and image processing applications. This study introduces a new computational approach for widely used vegetation indices, including the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Atmospherically Resistant Vegetation Index (ARVI). It also presents new tools for assessing chlorophyll, specifically the Leaf Area Index (LAI) and Chlorophyll Vegetative Index (CVI), as well as thermal indices like the Urban Thermal Field Variation Index (UTFVI) and Thermal Discomfort Index (TDI). Developed using Python, a popular programming language, within QGIS, the QSVI plugin features rapid processing capabilities and a user-friendly interface, making it particularly accessible for both researchers and educators. The effectiveness of the application was evaluated in the Sarıyer district of Istanbul using remote sensing data from the European Space Agency's Sentinel-2 and Sentinel-3 satellites. The results indicate that the QSVI plugin significantly reduces computation time compared to popular geographic information system (GIS) software, including ArcGIS, GRASS GIS, and SAGA GIS. For Sentinel-2 datasets, QSVI is, on average, 2.1 minutes faster than these applications. Additionally, for Sentinel-3 datasets, QSVI performs approximately 13.6 seconds faster than the others. These time savings highlight QSVI's efficiency in handling large datasets and demonstrate its advantages in environmental monitoring and analysis.
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Status: closed
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RC1: 'Comment on gi-2024-8', Anonymous Referee #1, 07 May 2025
This work, following some primary concerns raised during the review process, was improved to address some scientific concerns. In particular, the authors have clarified that, while NDVI calculation in QGIS is not in itself novel, the QSVI plugin adds value by integrating multiple vegetation, chlorophyll, and thermal indices into a streamlined, efficient, and user-friendly tool. The discussion has been improved to better articulate the scientific scope and practical utility of the plugin beyond educational purposes, especially highlighting the inclusion of chlorophyll and thermal indices as a potentially novel contribution. Although the educational motivation remains present, the authors have now positioned the plugin as a broadly useful resource for environmental monitoring, supporting both teaching and applied research. These clarifications make the manuscript a better fit for the journal’s scope.
Citation: https://doi.org/10.5194/gi-2024-8-RC1 -
AC1: 'Reply on RC1', Nuray Baş, 12 May 2025
Dear Referees and Editor,
I sincerely thank both reviewers for their valuable comments and helpful suggestions during the review process. I have extensively revised the manuscript, considering the main comments made in the first review, and I believe that these changes have clarified the scientific contribution of the manuscript.
In particular:
I recognize that NDVI is not a new feature in QGIS, and this has been clearly explained in the revised text. I emphasized that the main contribution of the QSVI plugin is its ability to efficiently calculate various vegetation, chlorophyll, and thermal indices in a user-friendly interface.
The plugin's ability to integrate lesser-known indices, such as CVI, LAI, UTFVI, and TDI, was highlighted as a key difference compared to similar tools.
This plugin is an effective tool not only for educational purposes but also for environmental monitoring and applied research.
Overall, the main contributions of this work are the computational efficiency provided by the plugin and the ease of access it offers users.
Thank you for your valuable contributions. Both the content and structure of my paper have improved significantly. Thank you for your interest and constructive feedback.
Kind regards,
Citation: https://doi.org/10.5194/gi-2024-8-AC1
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AC1: 'Reply on RC1', Nuray Baş, 12 May 2025
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RC2: 'Comment on gi-2024-8', Anonymous Referee #2, 07 May 2025
In this table you may find some major concerns raised during the review process and how these were addressed.
Concern How addressed in Revised Manuscript NDVI in QGIS is not novel The manuscript now clearly acknowledges that NDVI is a well-established index and that its implementation is not a scientific novelty. The focus has shifted to the efficiency and accessibility of multi-index processing using the QSVI plugin. Scientific novelty of chlorophyll and thermal indices manuscript elaborates on the inclusion of CVI, LAI, UTFVI, and TDI, offering a more robust justification for their use and distinguishing the plugin from existing tools. Relevance and scope beyond education The revised text better positions the plugin as a dual-purpose tool, highlighting its relevance not only in education but also in applied environmental monitoring, supported by processing speed comparisons and practical case studies. Clarification of plugin's core purpose The manuscript now frames computational efficiency and user accessibility for multi-index analysis as the core contributions, thereby aligning more closely with the journal's scope. Citation: https://doi.org/10.5194/gi-2024-8-RC2
Status: closed
-
RC1: 'Comment on gi-2024-8', Anonymous Referee #1, 07 May 2025
This work, following some primary concerns raised during the review process, was improved to address some scientific concerns. In particular, the authors have clarified that, while NDVI calculation in QGIS is not in itself novel, the QSVI plugin adds value by integrating multiple vegetation, chlorophyll, and thermal indices into a streamlined, efficient, and user-friendly tool. The discussion has been improved to better articulate the scientific scope and practical utility of the plugin beyond educational purposes, especially highlighting the inclusion of chlorophyll and thermal indices as a potentially novel contribution. Although the educational motivation remains present, the authors have now positioned the plugin as a broadly useful resource for environmental monitoring, supporting both teaching and applied research. These clarifications make the manuscript a better fit for the journal’s scope.
Citation: https://doi.org/10.5194/gi-2024-8-RC1 -
AC1: 'Reply on RC1', Nuray Baş, 12 May 2025
Dear Referees and Editor,
I sincerely thank both reviewers for their valuable comments and helpful suggestions during the review process. I have extensively revised the manuscript, considering the main comments made in the first review, and I believe that these changes have clarified the scientific contribution of the manuscript.
In particular:
I recognize that NDVI is not a new feature in QGIS, and this has been clearly explained in the revised text. I emphasized that the main contribution of the QSVI plugin is its ability to efficiently calculate various vegetation, chlorophyll, and thermal indices in a user-friendly interface.
The plugin's ability to integrate lesser-known indices, such as CVI, LAI, UTFVI, and TDI, was highlighted as a key difference compared to similar tools.
This plugin is an effective tool not only for educational purposes but also for environmental monitoring and applied research.
Overall, the main contributions of this work are the computational efficiency provided by the plugin and the ease of access it offers users.
Thank you for your valuable contributions. Both the content and structure of my paper have improved significantly. Thank you for your interest and constructive feedback.
Kind regards,
Citation: https://doi.org/10.5194/gi-2024-8-AC1
-
AC1: 'Reply on RC1', Nuray Baş, 12 May 2025
-
RC2: 'Comment on gi-2024-8', Anonymous Referee #2, 07 May 2025
In this table you may find some major concerns raised during the review process and how these were addressed.
Concern How addressed in Revised Manuscript NDVI in QGIS is not novel The manuscript now clearly acknowledges that NDVI is a well-established index and that its implementation is not a scientific novelty. The focus has shifted to the efficiency and accessibility of multi-index processing using the QSVI plugin. Scientific novelty of chlorophyll and thermal indices manuscript elaborates on the inclusion of CVI, LAI, UTFVI, and TDI, offering a more robust justification for their use and distinguishing the plugin from existing tools. Relevance and scope beyond education The revised text better positions the plugin as a dual-purpose tool, highlighting its relevance not only in education but also in applied environmental monitoring, supported by processing speed comparisons and practical case studies. Clarification of plugin's core purpose The manuscript now frames computational efficiency and user accessibility for multi-index analysis as the core contributions, thereby aligning more closely with the journal's scope. Citation: https://doi.org/10.5194/gi-2024-8-RC2
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