PONE-D-19-20112

Area extraction and spatiotemporal characteristics of winter wheat–summer maize in Shandong Province using NDVI time series

PLOS ONE

Dear Dr Zhao,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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The structure of the introduction need to be revised according to reviewers comments to put the study in the proper context. The description provided in each of the sections also need to be reviewed to make sure that only important information is retained. Description of important methodological parameters and their justification is missing for example. The discussion is also currently weak and needs to be strengthened by explaining the important aspects of the presented approach for practical application.

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We would appreciate receiving your revised manuscript by Nov 11 2019 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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Abel Chemura

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Authors of the manuscript entitled “Area extraction and spatiotemporal characteristics of winter wheat–summer maize in Shandong Province using NDVI time series” have presented a feasible approach to the mapping of crop rotation patterns involving wheat and maize using NDVI time series obtained from MODIS. However, the paper needs major improvements as given below:

1. The methodological novelty is not well articulated in the abstract and introduction.

2. The description of the study area can be reduced.

3. Paragraphs in the conclusion section should not be numbered.

4. Define the mtry and ntry parameters used in running the RF model

5. Proper English language editing is also required.

Reviewer #2: General

The importance of food crops such as maize and wheat is well known, and there is no need for motivation on that, what is lacking in the introduction is the motivation why is it so important to study the phenology of these food crops.

In the introduction, the authors introduce MODIS as a medium spatial resolution sensor (Page 3 line 54) and a few moments later, MODIS is now a low spatial resolution sensor (Page 3 line 58), please rectify. Also explain how do phenology metrics solve the problem of low spatial resolution?

The authors claimed to have used phenological metrics in this study. It is not clear which phenological metrics were used and why, how were these phenological metrics extracted, which algorithm (s) were used? All this information should be clear in the methods section.

Figure 4 shows NDVI temporal curves for five categories, the main objective of this study was to extract spatiotemporal characteristics of winter wheat–summer maize, therefore l do not see the relevance of the other categories presented here.

The description citing figure 4 is using months but the graphical presentation on figure 4 is using days, for the sake of consistency, l advice the authors to use either days or moths for both.

In the discussion, the authors claim that they have developed a tool for extracting spatiotemporal distribution information from large-scale winter wheat–summer maize planting from the MODIS-NDVI time series. However, the ‘newly developed’ tool was not mentioned, please clarify

Specific

Page 3 line 50: Give examples of the high spatial resolution images you are referring to

Page 4 line 66-68: The works of Li et al. [15] do not add value to the current work if their research findings are not reported, mentioning what their research focus only is not good enough

Page 8: Under the ‘smooth processing of time series’ section please provide a graphical presentation of raw and smoothed NDVI temporal data

Page 11 line 214: ‘land types’ do you mean land cover types or land use types?

Page 20 line 367: Replace ‘good agreement with reality’ with ‘good agreement with field/ground observation/measurements

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Reviewer #1: Yes: Dr. Lamin R. Mansaray

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

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PONE-D-19-20112R1

Area extraction and spatiotemporal characteristics of winter wheat–summer maize in Shandong Province using NDVI time series

PLOS ONE

Dear Dr Zhao,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

We would appreciate receiving your revised manuscript by Jan 04 2020 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Abel Chemura

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Authors have fully responded to my comments and I therefore recommend the current version for publication, subject to the recommendations of other reviewers.

Reviewer #2: Figure 4 does not have a legend, what is the red dotted and the black line representing?

Page 10 line 191: I suggest you change the section ‘Accuracy validation’ to accuracy assessment

Page 10 line 194: Consider rephrasing the sentence which begins with ‘To evaluate the comprehensiveness and objectivity of..’ since the previous sentence begins exactly the same

Page 10 line 196-197: ‘high-resolution images from google earth’ Which resolution are you referring to? Spatial, spectral, temporal?

Page 11 line 216: The first heading on the results section needs attention, which remote sensing ‘approaches’ are you referring to? The authors should specify the remote sensing approaches they used

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Dr. Lamin R. Mansaray

Reviewer #2: Yes: Trylee Nyasha Matongera

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

Area extraction and spatiotemporal characteristics of winter wheat–summer maize in Shandong Province using NDVI time series

PONE-D-19-20112R2

Dear Dr. Zhao,

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

Within one week, you will receive an e-mail containing information on the amendments required prior to publication. When all required modifications have been addressed, you will receive a formal acceptance letter and your manuscript will proceed to our production department and be scheduled for publication.

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With kind regards,

Abel Chemura

Academic Editor

PLOS ONE

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