Review Reports - Hydrographic Objects’ Domains in Ship Route Planning in Restricted Areas

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper has a certain degree of novelty, especially with the introduction of the concept of “Hydrological Object Domain,” which has theoretical value in improving the scientific basis of ship route planning and collision avoidance decision-making. However, the manuscript still has many issues overall, as detailed below:

Chapter numbering is confusing, for example, “1. Introduction” and “1. State of the Art” appear in parallel, leading to logical inconsistency.
Table numbering is duplicated, such as “Table 5. Domains of the 'medium' ship.” and “Table 5. Domains of the 'small' ship.”
Language expressions are imprecise, for example, line 171: “the position of the center of the ellipse Xc and Yc and.” It is recommended to carefully proofread the entire manuscript.
Punctuation is used improperly, for example, line 199: “static data: e.g. MMSI vessel identifier, status, type, length, breadth” should not end with a colon. Similar punctuation issues are found throughout the text; careful proofreading is advised.
Paragraph indentation and formatting are inconsistent, such as in Sections 2.4, 2.5, and line 356. The overall layout is not standardized. It is recommended to unify the formatting to improve readability and professionalism.
The analysis of figures and tables is insufficient in depth. Although the manuscript includes a large number of schematic and result figures (e.g., Tables 3-5, Fig.17-Fig.19), most are merely listed without further analysis or elaboration. It is recommended that the authors expand the discussion and analysis around the research questions.
The “State of the Art” section mainly lists certain regulations and AIS technical basics, without systematically reviewing existing research on “ship domains” and “hydrological object domains,” and without forming an effective connection with the present study. It is recommended to expand the literature review, and clearly define the research gap and innovation points.
Line 270 mentions several cartographic projection methods (e.g., Gauss-Kruger, UTM, Mercator), but does not specify which one is actually used for coordinate conversion in this paper. It is recommended to specify the projection method and parameter settings used.
In Section 2.5, the concepts of maximum inscribed ellipse and minimum bounding ellipse are only mentioned theoretically, without any related calculation or parameter fitting methods. It is recommended to add the relevant details and descriptions to enhance methodological reliability and persuasiveness.
Although the concept of “Hydrological Object Domain” has a certain degree of theoretical innovation, the current experiment only analyzes a single lighthouse object, which makes it difficult to fully validate its effectiveness. It is recommended to supplement experiments on different types of hydrological objects to further enhance the practical value and reliability of the study.

Author Response

Authors’ response to Reviewer

Dear Reviewer

We sincerely thank you for taking the time to review our paper. Your comments and questions are valuable and interesting to us. Based on your suggestions and concerns, we have revised the manuscript, added new information, and provided additional explanations. As a result, we believe the findings of our study will now be easier to interpret. The main changes made to the manuscript have been highlighted in yellow for better visibility.

Below, we provide detailed responses to your comments.

Chapter numbering is confusing, for example, “1. Introduction” and “1. State of the Art” appear in parallel, leading to logical inconsistency.

Thank You for this remark. Simple mistake during formatting. Corrected and marked in text.

Table numbering is duplicated, such as “Table 5. Domains of the 'medium' ship.” and “Table 5. Domains of the 'small' ship.”

Thank You for this remark. Simple mistake during formatting. Corrected and marked in text.

Language expressions are imprecise, for example, line 171: “the position of the center of the ellipse Xc and Yc and.” It is recommended to carefully proofread the entire manuscript.

Thank You for this remark, text corrected.

Punctuation is used improperly, for example, line 199: “static data: e.g. MMSI vessel identifier, status, type, length, breadth” should not end with a colon. Similar punctuation issues are found throughout the text; careful proofreading is advised.

Thank You for this remark, text corrected.

Paragraph indentation and formatting are inconsistent, such as in Sections 2.4, 2.5, and line 356. The overall layout is not standardized. It is recommended to unify the formatting to improve readability and professionalism.

Thank You for this remark, text corrected.

The analysis of figures and tables is insufficient in depth. Although the manuscript includes a large number of schematic and result figures (e.g., Tables 3-5, Fig.17-Fig.19), most are merely listed without further analysis or elaboration. It is recommended that the authors expand the discussion and analysis around the research questions.

Thank You for this comment. Discussion section has been expanded.

The “State of the Art” section mainly lists certain regulations and AIS technical basics, without systematically reviewing existing research on “ship domains” and “hydrological object domains,” and without forming an effective connection with the present study. It is recommended to expand the literature review, and clearly define the research gap and innovation points.

Thank you for your comment. The State of the Art section has been expanded.

Line 270 mentions several cartographic projection methods (e.g., Gauss-Kruger, UTM, Mercator), but does not specify which one is actually used for coordinate conversion in this paper. It is recommended to specify the projection method and parameter settings used.

Thank you for Your remark.

The transformation from the geographic to the Cartesian coordinate system was performed using the Gauss–Krüger model extension – Universal Transverse Mercator (UTM). The corresponding addition has been incorporated into the text.

In Section 2.5, the concepts of maximum inscribed ellipse and minimum bounding ellipse are only mentioned theoretically, without any related calculation or parameter fitting methods. It is recommended to add the relevant details and descriptions to enhance methodological reliability and persuasiveness.

Thank you for Your remark. The content of the article has been supplemented and refined in accordance with the reviewer’s comment.

Although the concept of “Hydrological Object Domain” has a certain degree of theoretical innovation, the current experiment only analyzes a single lighthouse object, which makes it difficult to fully validate its effectiveness. It is recommended to supplement experiments on different types of hydrological objects to further enhance the practical value and reliability of the study.

Thank You for this remark.

The authors proposed a classification of hydrographic objects (Figure 1) in connection with the need to define prohibited areas around them. A literature review has shown that the primary method is based on the safety contour. This method does not take into account the criterion of a safe distance from these objects. An example may be the analysed point object. The authors undertook the development of a methodology for determining such areas, taking into account the above-mentioned safe distance criterion. Due to the diverse nature of these objects, it was assumed that different methods would be applied. In all cases, AIS data will serve as the basis. This article presents the first of the methods within the proposed methodology. The concepts of minimum, mean, and maximum domains for point hydrographic objects are introduced. The authors plan further research on determining domains for objects of other types.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The abstract is very confusing and should be rewritten more clearly. The same applies to the conclusions chapter, where no results are mentioned, and it is not clear what the objective of your work is or why you are working on it. Overall, the manuscript lacks clarity and coherence in its exposition, which makes it difficult for the reader to fully grasp the purpose and contributions of your research.

Throughout the text, many statements are not supported by references, particularly in the introduction and in the first part of the method section. For example, in the conclusions you state: "There is a need to designate hydrographic object domains to ensure safe navigation near hydrographic objects, including for the designation of NoGo areas on navigation charts." This need is never explicitly demonstrated or backed up by evidence anywhere in the manuscript, and this is a recurring issue throughout the paper.

The state of the art section is extremely short and, in its current form, cannot be considered a proper chapter. Although some articles are cited, the section does not provide a real overview of the topic, nor does it explain how it is addressed by the scientific community. It should include a discussion of similar works, a clear motivation for the research, and the identification of the research gap that this study aims to fill. Moreover, when citing an article, it is not sufficient to mention it: a brief description of the work and its relevance to your study should be included.

Since you make use of AIS data, I strongly recommend adding a dedicated subsection explaining AIS and its usage. In this context, it would be appropriate to cite the following paper, which discusses the use of AIS virtual AtoN for navigation in the Lagoon of Venice:

- Di Ciaccio, F., Menegazzo, P., & Troisi, S. (2019). Optimization of the maritime signaling system in the lagoon of Venice. Sensors, 19(5), 1216.

Several issues also concern the figures. For instance, Figure 1 ("Categorization of chart objects [source: own]") does not clearly state the authorship of the image, and this note should either be removed or properly clarified. More importantly, it is not explained on what basis this categorization is proposed, nor is it discussed whether other categorizations are already available and commonly used by the maritime community. The same problem applies to the subdivision of ships by size: you state that "The research was conducted for ships of different sizes: small, medium, large and huge (Table 1). The division was dictated, among other things, by the specific nature of the recommended shipping routes for ships in the analysed area." However, this is not discussed or supported, making it unclear why this particular categorization was chosen.

All figures and tables throughout the manuscript lack proper captions. Captions should explain what the image represents and provide enough context for the reader to understand it without referring back to the text. As an example, Figure 5 is captioned simply "Ellipse", with no further explanation. This problem occurs consistently and should be addressed carefully. Moreover, are you sure that you need to show what an ellipse looks like? This figure, as it stands, adds no scientific value to the manuscript.

While the method itself could be considered understandable, the way it is described is often unclear, making it hard to follow the reasoning behind the approach and its application. Sentences like "the first three define the zones in a crisp manner. The fourth domain visualises zones with intermediate levels (Figures 12, 13), similarly to the fuzzy domain of a ship" are vague and lack the necessary scientific precision and detail.

The discussion chapter is too short to be a standalone section and adds little value in its current state. I suggest merging it with the results chapter to create a comprehensive Results and Discussion section.

Furthermore, the results presented are not particularly interesting or insightful, and there is no proper discussion of their usefulness. The manuscript lacks practical examples or applied considerations, even in relation to the case study, which would be essential to demonstrate the real-world value of the proposed approach.

Finally, the overall writing quality needs significant improvement through proper language editing to make the manuscript clearer and more readable.

In its current form, this manuscript requires major revisions before it can be considered for publication.

Author Response

Authors’ response to Reviewer

Dear Reviewer

Below, we provide detailed responses to your comments.

The abstract is very confusing and should be rewritten more clearly. The same applies to the conclusions chapter, where no results are mentioned, and it is not clear what the objective of your work is or why you are working on it. Overall, the manuscript lacks clarity and coherence in its exposition, which makes it difficult for the reader to fully grasp the purpose and contributions of your research.

Thank You for this remark.

In accordance with the reviewer’s comments, the abstract and conclusions have been revised.

Throughout the text, many statements are not supported by references, particularly in the introduction and in the first part of the method section. For example, in the conclusions you state: "There is a need to designate hydrographic object domains to ensure safe navigation near hydrographic objects, including for the designation of NoGo areas on navigation charts." This need is never explicitly demonstrated or backed up by evidence anywhere in the manuscript, and this is a recurring issue throughout the paper.

It is not described in the text, as it is covered by the latest IHO standards (S-100) and work related to the development of electronic nautical charts (ENC).

The state of the art section is extremely short and, in its current form, cannot be considered a proper chapter. Although some articles are cited, the section does not provide a real overview of the topic, nor does it explain how it is addressed by the scientific community. It should include a discussion of similar works, a clear motivation for the research, and the identification of the research gap that this study aims to fill. Moreover, when citing an article, it is not sufficient to mention it: a brief description of the work and its relevance to your study should be included.

Thank you for your comment. The “State of the Art” section has been expanded in accordance with the reviewer’s remarks.

Since you make use of AIS data, I strongly recommend adding a dedicated subsection explaining AIS and its usage. In this context, it would be appropriate to cite the following paper, which discusses the use of AIS virtual AtoN for navigation in the Lagoon of Venice:

- Di Ciaccio, F., Menegazzo, P., & Troisi, S. (2019). Optimization of the maritime signaling system in the lagoon of Venice. Sensors, 19(5), 1216.

Thank you for your comment. The reviewer’s suggestion has been included in the bibliography. The system’s functionalities, as well as its advantages and disadvantages, are the subject of separate studies. The article uses standard data transmitted by the system. Due to the extensive literature and the widespread use of AIS in navigation, only a general description of the system has been provided.

Several issues also concern the figures. For instance, Figure 1 ("Categorization of chart objects [source: own]") does not clearly state the authorship of the image, and this note should either be removed or properly clarified. More importantly, it is not explained on what basis this categorization is proposed, nor is it discussed whether other categorizations are already available and commonly used by the maritime community.

Thank you for your comment. The text has been supplemented and the figure title has been changed to “Proposed categorization of hydrographic objects occurring on nautical charts.” The basic object types (point, polygon, line) correspond to the IHO classification.

The same problem applies to the subdivision of ships by size: you state that "The research was conducted for ships of different sizes: small, medium, large and huge (Table 1). The division was dictated, among other things, by the specific nature of the recommended shipping routes for ships in the analysed area." However, this is not discussed or supported, making it unclear why this particular categorization was chosen.

Thank you for your comment. The proposed classification reflects the commonly used division of ships in navigation according to size: coaster (here “small ship”), short-trade ship (here “medium ship”), handy size (here “large ship”), panamax (here “huge ship”). The article text has been supplemented (lines …).

All figures and tables throughout the manuscript lack proper captions. Captions should explain what the image represents and provide enough context for the reader to understand it without referring back to the text. As an example, Figure 5 is captioned simply "Ellipse", with no further explanation. This problem occurs consistently and should be addressed carefully. Moreover, are you sure that you need to show what an ellipse looks like? This figure, as it stands, adds no scientific value to the manuscript.

Thank you for your comment. In accordance with the recommendation, Figure 5 has been removed.

While the method itself could be considered understandable, the way it is described is often unclear, making it hard to follow the reasoning behind the approach and its application. Sentences like "the first three define the zones in a crisp manner. The fourth domain visualises zones with intermediate levels (Figures 12, 13), similarly to the fuzzy domain of a ship" are vague and lack the necessary scientific precision and detail.

Thank you for Your comment. In accordance with the suggestion, the text has been modified. The term “crisp domain” has been replaced with “sharp domain.” The concept of “fuzzy domain” has been introduced using the terminology of fuzzy logic. An example in the context of navigational issues is the ship’s fuzzy domain.

The discussion chapter is too short to be a standalone section and adds little value in its current state. I suggest merging it with the results chapter to create a comprehensive Results and Discussion section.

Thank you for Your comment. The Discussion has been expanded and will continue to constitute a separate chapter.

Furthermore, the results presented are not particularly interesting or insightful, and there is no proper discussion of their usefulness. The manuscript lacks practical examples or applied considerations, even in relation to the case study, which would be essential to demonstrate the real-world value of the proposed approach.

Thank you for Your comment. Discussion has been expanded.

Finally, the overall writing quality needs significant improvement through proper language editing to make the manuscript clearer and more readable.

Thank you for your comment. Corrections have been made in accordance with the suggestions, and the text has undergone another proofreading.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Although different domain concepts are proposed, the abstract does not elaborate on the specific algorithms and model parameters for domain definition, such as how the size of the domain of this ship is affected by the type of ship and the navigation environment (wind, waves, currents, etc.)?
Although AIS data collection and analysis have been carried out, hydrological target classification and domain determination methods have been proposed, which belong to the basic work of ship voyage planning research, the author should highlight more of his own contributions, innovation and differences from other algorithms.
Figure 9d (the basic domain of the giant ship) shows that its domain range (brown ellipse) is significantly smaller than that of the large ship (Figure 9c), which contradicts the core assumption that "the larger the ship type, the larger the domain".
It is necessary to add the latest papers from the past three years. Do not include papers on industry standards, but rather those related to algorithms in this article. This can enhance the credibility and advantages of this article.
Professional terms should have their full names when they first appear.
The abstract of the paper does not conform to the four elements of an abstract (purpose, method, result, and conclusion).
The depth of the discussion in the paper is insufficient. There is no data support, and the impact of improvement methods is not discussed. The discussion only focuses on the roles and applicability in different fields, which is incorrect.

Author Response

Authors’ response to Reviewer

Dear Reviewer

Below, we provide detailed responses to your comments.

Although different domain concepts are proposed, the abstract does not elaborate on the specific algorithms and model parameters for domain definition, such as how the size of the domain of this ship is affected by the type of ship and the navigation environment (wind, waves, currents, etc.)?

The safety of a vessel is influenced by numerous factors related to the vessel itself, the area of operation, hydrometeorological conditions, and the available navigational systems. In the case of manned vessels and semi-autonomous vessels with a skeleton crew, the human factor also plays a role. In general, hydrometeorological conditions are not taken into account at the voyage planning stage. They are considered in subsequent stages of the voyage—route optimisation and monitoring—based on up-to-date forecasts and weather analyses.

The proposed method is based on AIS-recorded vessel traffic data. These are records of various ships’ voyages collected according to AIS standards and do not include weather data. The inclusion of wind, waves, currents, etc., in the process of determining the domain of a hydrographic object is possible under simulation conditions using a full mission bridge simulator. At the current stage of research, using AIS data, the influence of varying hydrometeorological conditions on the parameters of a hydrographic object’s domain has not been considered.

Although AIS data collection and analysis have been carried out, hydrological target classification and domain determination methods have been proposed, which belong to the basic work of ship voyage planning research, the author should highlight more of his own contributions, innovation and differences from other algorithms.

Thank you for Your comment. In the available literature, the safety criteria are generally defined by the safety contour and the allowable cross-track error (XTE). The criterion of a safe passing distance from hydrographic objects is not taken into account. The novel elements of the article are the proposed hydrographic object domains and the methodology for their determination. These can be used for the automatic identification of “No Go” areas in the ship voyage planning process.

Figure 9d (the basic domain of the giant ship) shows that its domain range (brown ellipse) is significantly smaller than that of the large ship (Figure 9c), which contradicts the core assumption that "the larger the ship type, the larger the domain".

Thank You for this remark.

This is because the basic domain is strictly based on all observations, while the actual observed ship routes are not deterministic and are characterized by a certain degree of randomness. In such cases, the routes that deviate from the average norm have a sig-nificant impact on the final result (a deterministic inscribed ellipse), significantly dis-torting the reasoning. Therefore, it was proposed to divide the results in order to obtain multiple ellipses (e.g., daily). This moved the considerations from the deterministic to the stochastic domain. The calculated ellipses, representing time domains (daily), can be subjected to elementary statistical processing and, on this basis is possible to deter-mine:

the minimum domain - as inscribed in the time (daily , temporary) domains,
the average (mean) domain with parameters being the average values of the time (daily)temporary domains, and
the maximum domain – as bounding the time (daily)temporary domains

Grzesiek tak ma być??

It is necessary to add the latest papers from the past three years. Do not include papers on industry standards, but rather those related to algorithms in this article. This can enhance the credibility and advantages of this article.

Thank you for Your comment. The “State of the Art” and “References” sections has been expanded in accordance with the reviewer’s remarks.

Professional terms should have their full names when they first appear.

Thank you for Your comment. Text corrected.

The abstract of the paper does not conform to the four elements of an abstract (purpose, method, result, and conclusion).

Thank You for this remark. The abstract has been revised in accordance with the reviewer’s comments to read as:

The basic requirement for ship voyage planning is to determine a safe route while meeting certain safety and economic criteria. ECDIS systems are a commonly used tool for this purpose. Route planning is normally accomplished by setting route cross track limit - XTE. The XTE value can be adjusted on individual sections of the planned route. As a complementary criterion, the own ship domain is proposed, understood as the area around the ship which is to remain free of other objects. The concept of a hydrographic object domain, analogous to the vessel domain, is proposed. A hydrographic object domain complements existing safety criteria, particularly the criterion of a safe passing distance, and can also be used to define the safe cross-track error (XTE) limit. A methodology for determining such domains is presented, consisting of a vessel track analysis method (based on AIS data) and specific methods for determining domains for different types of hydrographic objects. The method for determining minimum, average, and maximum domains for point objects is described in detail. This paper presents the results of a study on the determination of hydrographic objects domains. Different types of these objects are considered, and their classification is proposed. A methodology for determining the domains of these objects is presented. Based on actual recorded Automatic Identification System (AIS) data for conventional ships, domains of fixed objects and navigational hazards have been determined. Domains of hydrographic objects can be an important complement to the mentioned deviation limits in route planning for both conventionally operated vessels, remotely controlled from land-based centers and autonomous vessels.

The depth of the discussion in the paper is insufficient. There is no data support, and the impact of improvement methods is not discussed. The discussion only focuses on the roles and applicability in different fields, which is incorrect.

Thank you for Your comment. The Discussion has been expanded.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript has been improved according to the suggested revisions.

I appreciate the authors' efforts in addressing the concerns raised.

I have no further comments.

Author Response

Dear Reviewer,

We would like to sincerely thank you for taking the time to review our paper. Your comments and questions are highly valuable and insightful.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

please refer to the attached document

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

We would like to sincerely thank you for taking the time to review our paper. Your comments and questions are highly valuable and insightful. Based on your suggestions and concerns, we have revised the manuscript, incorporated new information, and added further explanations. We believe these changes make the findings of our study clearer and easier to interpret.

For better visibility, the main revisions in the manuscript have been highlighted in yellow.

Below, we provide detailed, point-by-point responses to your comments (in blue).

Date of this review

19 Aug 2025 19:01:05

Dear Authors, Thank you for taking my suggestions into consideration. Please find below my final remarks and recommendation (in red).

Authors’ response to Reviewer Dear Reviewer We sincerely thank you for taking the time to review our paper. Your comments and questions are valuable and interesting to us. Based on your suggestions and concerns, we have revised the manuscript, added new information, and provided additional explanations. As a result, we believe the findings of our study will now be easier to interpret. The main changes made to the manuscript have been highlighted in yellow for better visibility. Below, we provide detailed responses to your comments.

The abstract is very confusing and should be rewritten more clearly. The same applies to the conclusions chapter, where no results are mentioned, and it is not clear what the objective of your work is or why you are working on it. Overall, the manuscript lacks clarity and coherence in its exposition, which makes it difficult for the reader to fully grasp the purpose and contributions of your research.

Thank You for this remark. In accordance with the reviewer’s comments, the abstract and conclusions have been revised.

Although revised, the abstract and conclusions could still be improved (avoiding repetitions inside the sentences). These sections must clearly and concisely convey the objective of the work, the adopted methodology, and the key findings. Without this information, the reader struggles to understand the scientific relevance and contributions of the study. It is essential not to assume prior knowledge, guiding the reader with a clear and informative summary is a fundamental requirement.

Thank You for this remark.

The abstract has been revised again, with the following addition:

The domains of hydrographic objects and the methods for their determination proposed by the authors, which define passing distances from hydrographic objects, may be applied to the delineation of ‘NoGo areas’ around them.

Throughout the text, many statements are not supported by references, particularly in the introduction and in the first part of the method section. For example, in the conclusions you state: "There is a need to designate hydrographic object domains to ensure safe navigation near hydrographic objects, including for the designation of NoGo areas on navigation charts." This need is never explicitly demonstrated or backed up by evidence anywhere in the manuscript, and this is a recurring issue throughout the paper.

It is not described in the text, as it is covered by the latest IHO standards (S-100) and work related to the development of electronic nautical charts (ENC).

Stating a need without providing adequate references weakens the scientific foundation of the article. Even when referencing well-established standards (e.g., IHO S-100), it is important to briefly introduce them in the text to offer proper context. A short but clear explanation helps readers understand why the issue is relevant and substantiates the claims being made.

Thank You for this remark.

The following addition was made to the text:

The S-100 framework nautical charts, to be introduced into navigation from 1 January 2026, provide significantly more data and offer new capabilities compared to the navigational charts currently in use. Among other improvements, the amount of bathymetric and environmental data (currents, tides, weather) has been substantially increased. By utilizing such high-resolution data, it becomes possible to automatically delineate ‘NoGo areas,’ i.e., regions encompassing clusters of hazards, a task that until now has been performed manually.

The state of the art section is extremely short and, in its current form, cannot be considered a proper chapter. Although some articles are cited, the section does not provide a real overview of the topic, nor does it explain how it is addressed by the scientific community. It should include a discussion of similar works, a clear motivation for the research, and the identification of the research gap that this study aims to fill. Moreover, when citing an article, it is not sufficient to mention it: a brief description of the work and its relevance to your study should be included.

Thank you for your comment. The “State of the Art” section has been expanded in accordance with the reviewer’s remarks.

Simply listing related works does not constitute a proper state-of-the-art section. This part should offer a structured overview of the field, highlight how the topic has been approached in previous studies, and identify the specific gap this research intends to address. Cited works should not only be mentioned but also briefly explained in relation to their relevance to your study.

Thank you for your comment.

The following addition was made to the text:

The literature addresses issues related to voyage planning. Voyage planning consists in determining successive waypoints, either manually by the navigator or automatically by systems such as ‘Route Planner.’ Various aspects of voyage planning and execution are analyzed in the literature, taking into account the criteria and tools available in ECDIS systems to support this process. These tools allow verification of the route planned by the navigator using designated waypoints. Verification involves checking whether the intended track, defined by waypoints and permissible cross-track error (XTE) limits, intersects the safety contour, isolated navigational hazards, or restricted and special areas. Additionally, it is possible to introduce ‘NoGo Areas.’ The safety contour is understood as the one selected by the navigator from the ENC database. It necessitates corrections of waypoint positions and XTE values for individual route segments. Current IHO work within the S-100 standard framework allows for the automatic generation of ‘NoGo Areas.’ The hydrographic object domains and methods of their determination proposed by the authors, defining passing distances from hydrographic objects, may be applied to the delineation of ‘NoGo Areas’ around them.

Since you make use of AIS data, I strongly recommend adding a dedicated subsection explaining AIS and its usage. In this context, it would be appropriate to cite the following paper, which discusses the use of AIS virtual AtoN for navigation in the Lagoon of Venice: - Di Ciaccio, F., Menegazzo, P., & Troisi, S. (2019). Optimization of the maritime signaling system in the lagoon of Venice. Sensors, 19(5), 1216.

The description of AIS remains too general. Since AIS data are a core component of the analysis, the article must include a dedicated subsection explaining the system and explicitly detailing the specifications used. Furthermore, the recommended reference (Di Ciaccio et al., 2019) has not been properly cited, despite being a valuable contribution that illustrates a real world application of AIS and strengthens the technological background of your work.

Thank you for your comment.

The following addition was made to the text:

In the AIS system, vessels regularly transmit both static data, including identification details, ship type, dimensions, and draught, as well as dynamic data, such as current position, draught, course, and speed. In this study, data on ship size and position were used. AIS signals are also transmitted by AtoN (Aids to Navigation), both physically existing and virtual.

Several issues also concern the figures. For instance, Figure 1 ("Categorization of chart objects [source: own]") does not clearly state the authorship of the image, and this note should either be removed or properly clarified. More importantly, it is not explained on what basis this categorization is proposed, nor is it discussed whether other categorizations are already available and commonly used by the maritime community.

Even if the categorization aligns with IHO standards, this is not clearly stated in the text. It is important to explicitly reference the origin of the proposed classification to avoid ambiguity and ensure methodological transparency.

Thank you for your comment.

Figure 1 has been modified, and the following addition was made to the text:

The categorization proposed by the authors for determining prohibited areas around objects is presented in Figure 1. The basic object types (point, polygon, line) correspond to the IHO classification. The authors proposed a categorization of such objects and provided illustrative examples.

The same problem applies to the subdivision of ships by size: you state that "The research was conducted for ships of different sizes: small, medium, large and huge (Table 1). The division was dictated, among other things, by the specific nature of the recommended shipping routes for ships in the analysed area." However, this is not discussed or supported, making it unclear why this particular categorization was chosen.

Although this classification is widely used in maritime contexts, a scientific article requires explicit references, even for well-known conventions. Citing a source enhances the article’s credibility and helps readers unfamiliar with the domain understand the basis of the categorization.

Thank you for your comment.

The following addition was made to the text:

The basic ship parameters considered in route planning are its size—length and draught. It is not feasible to determine a domain for a vessel of arbitrary length and draught. The adopted division into groups by length was established arbitrarily, based on the navigator’s experience. Conventional and widely used shipping terminology for ship size groups was applied: coaster, short-trade ship, handy size, and panamax. For clarity, especially for readers less familiar with this subject, the corresponding simplified terms were introduced: ‘small,’ ‘medium’, large,’ and ‘panamax’ ship.

All figures and tables throughout the manuscript lack proper captions. Captions should explain what the image represents and provide enough context for the reader to understand it without referring back to the text. As an example, Figure 5 is captioned simply "Ellipse", with no further explanation. This problem occurs consistently and should be addressed carefully. Moreover, are you sure that you need to show what an ellipse looks like? This figure, as it stands, adds no scientific value to the manuscript.

Thank you for your comment. In accordance with the recommendation, Figure 5 has been removed.

All figures and tables must include detailed captions that clearly describe their content. Captions should provide enough information to be understood independently from the main text.

Thank you for your comment.

The descriptions of the figures were refined, and supplementary legends were introduced.

While the method itself could be considered understandable, the way it is described is often unclear, making it hard to follow the reasoning behind the approach and its application. Sentences like "the first three define the zones in a crisp manner. The fourth domain visualizes zones with intermediate levels (Figures 12, 13), similarly to the fuzzy domain of a ship" are vague and lack the necessary scientific precision and detail.

Terms like “fuzzy domain” should be explained more thoroughly. Even though these concepts may be familiar to experts, scientific articles should also be accessible to non-specialist readers. Providing a clearer explanation and contextualization improves readability and enhances the article’s educational value.

Thank you for your comment.

The concept of the ‘fuzzy domain’ was clarified in the text as follows:

Subsequently, the fuzzy domain of an object was introduced based on fuzzy set theory (Figure 13a–d), analogously to the ship’s fuzzy domain. The fundamental concept of this theory is the fuzzy set, which allows an element to belong to a set with a degree ranging from 0 to 1. A membership degree of 0 indicates that the element does not belong to the set, a degree of 1 denotes full membership, and values within the interval (0,1) represent partial membership. The coefficient CR is interpreted as the degree of membership in the fuzzy set defined as the fuzzy domain of a hydrographic object. This approach enables continuous assessment of the current level of intrusion into the area surrounding the object, based on the CR factor, and facilitates tracking its direction of change.

The discussion chapter is too short to be a standalone section and adds little value in its current state. I suggest merging it with the results chapter to create a comprehensive Results and Discussion section.

Thank you for Your comment. The Discussion has been expanded and will continue to constitute a separate chapter.

Furthermore, the results presented are not particularly interesting or insightful, and there is no proper discussion of their usefulness. The manuscript lacks practical examples or applied considerations, even in relation to the case study, which would be essential to demonstrate the real-world value of the proposed approach. Thank you for Your comment. Discussion has been expanded. 11. Finally, the overall writing quality needs significant improvement through proper language editing to make the manuscript clearer and more readable.

Thank you for your comment. Corrections have been made in accordance with the suggestions, and the text has undergone another proofreading.

Some newly introduced edits have introduced additional ambiguities. A thorough language revision is highly recommended to enhance clarity, flow, and overall readability.

Thank you for your comment.

Language revised.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript has been updated according to most of the previous comments. However, there are still some minor problems to be improved as follows.
1. The manuscript’s main contributions should be stated clearly point by point in Section 1 Introduction. Lines 61-83 give some descriptions about the motivations, namely, NoGo areas, of this study. However, the novel ideas of this manuscript are still unclear.
2. Section “State of the Art” gives some brief introductions about voyage planning. MASS voyage planning is a hot topic in recent years. Lots of literatures are listed in this field. However, the literatures are still scarce with regard to the voyage planning about “NoGo areas”. So, it is quite difficult for the reviewer to determine the contribution of this manuscript.
3. AIS data are analysed and discussed in this manuscript. However, AIS data contains a lot of information. What kinds of information are used for voyage planning?
4. The advantages of incorporating AIS data should be in Section 1 Introduction. These advantages should be illustrated with comparison to the traditional methods.

Author Response

Dear Reviewer,

For better visibility, the main revisions in the manuscript have been highlighted in yellow.

Below, we provide detailed, point-by-point responses to your comments (in blue).

The manuscript has been updated according to most of the previous comments. However, there are still some minor problems to be improved as follows.

The manuscript’s main contributions should be stated clearly point by point in Section 1 Introduction. Lines 61-83 give some descriptions about the motivations, namely, NoGo areas, of this study. However, the novel ideas of this manuscript are still unclear.

Thank you for your comment.

Figure 1 has been modified, and the following addition was made to the text:

The following addition was made to the text:

Section “State of the Art” gives some brief introductions about voyage planning. MASS voyage planning is a hot topic in recent years. Lots of literatures are listed in this field. However, the literatures are still scarce with regard to the voyage planning about “NoGo areas”. So, it is quite difficult for the reviewer to determine the contribution of this manuscript.

Thank You for this remark.

The following addition was made to the text:

The determination of hydrographic object domains constitutes the first stage in the automatic delineation of ‘NoGo areas.

AIS data are analysed and discussed in this manuscript. However, AIS data contains a lot of information. What kinds of information are used for voyage planning?

Thank You for this remark.

AIS data is generally not used for voyage planning (but it is used later for voyage monitoring).

The following addition was made to the text:

The study used data on ship sizes as well as their recorded positions.

The advantages of incorporating AIS data should be in Section 1 Introduction. These advantages should be illustrated with comparison to the traditional methods.

Thank You for this remark.

The following addition was made to the text:

The ECDIS system is used for route planning. In general, AIS data are employed during voyages for route monitoring and hazard avoidance. These data are displayed on AIS receivers or ECDIS screens. Traditionally, AIS data have not been used for voyage planning, which relied instead on nautical charts.

AIS data significantly complement ENC data. AIS transponders installed on both floating and fixed objects (e.g., buoys, beacons) enable voyage monitoring and hazard avoidance. Moreover, such data can be used to define areas around these objects. One example is the delineation of safety zones around ships. In this study, the use of AIS data is proposed for determining recommended safety areas/zones around fixed objects.

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

I would like to thank the authors for the effort made in revising the manuscript. Several improvements have been implemented, such as a clearer methodology section, the removal or adjustment of some figures, and the inclusion of additional references.

I still suggest to slightly review the manuscript to make it suitable for publication:

Abstract and Conclusions. Despite the revisions, these sections remain a little unclear and repetitive. I suggest to revise them to help readers to understand the novelty and relevance of the work.

State of the Art and Related Works. The section has been expanded, but it is still presented as a list of references rather than a proper overview. Moreover, in the current structure (lines 120–157), this content is placed at the end of the introduction. Usually, when a manuscript includes a description of the structure of chapters, this marks the closure of the introduction. For this reason, I strongly recommend creating a dedicated Chapter 2: Related Works using the material from lines 120–157, and then renumbering the current Materials and Methods as Chapter 3. This would provide a clearer structure and align the paper with common scientific standards.

Section 2.5. Method for determining the domain for a point type object. Please check this section as it could be better organized.

Overall, the paper has improved compared to the previous version, but the exposition could still be improved before publication.

Author Response

Dear Reviewer,

Comments and Suggestions for Authors

I would like to thank the authors for the effort made in revising the manuscript. Some improvements have been implemented, such as a clearer methodology section, the removal or adjustment of some figures, and the inclusion of additional references.

I still suggest to slightly review the manuscript to make it suitable for publication:

Abstract and Conclusions.Despite the revisions, these sections remain a little unclear and repetitive. I suggest to revise them to help readers to understand the novelty and relevance of the work.

Thank You for this comment.

The Abstract and Conclusions have been revised. The changes are marked in the file Manuscript with highlighted changes. Redundant repetitions have been removed.

State of the Art and Related Works.
- The section has been expanded, but it is still presented as a list of references rather than a proper overview.

Thank You for this comment.

The authors are not aware of related works concerning hydrographic object domains. For this reason, they have presented only works related to the broader issues addressed in the article. These include, among others, ship route planning and route monitoring, where the proposed domain may be applied.

Moreover, in the current structure (lines 120–157), this content is placed at the end of the introduction. Usually, when a manuscript includes a description of the structure of chapters, this marks the closure of the introduction.

Thank You for this comment.

The Introduction has been revised by moving the description of the structure of chapters in accordance with the comments

For this reason, I strongly recommendcreating a dedicated Chapter 2: Related Works using the material from lines 120–157, and then renumbering the current Materials and Methods as Chapter 3. This would provide a clearer structure and align the paper with common scientific standards.

Thank You for this comment.

Since there are no publications concerning hydrographic object domains, the description of related works has not been extended, and the restructuring of the article’s chapters has been abandoned.

Section 2.5.Method for determining the domain for a point type object. Please check this section as it could be better organized.

Thank You for this comment.

In accordance with the previous reviewers’ comments, the authors have provided a detailed description of the proposed method for determining the domains of point hydrographic objects, including additional illustrations and step-by-step explanations of the method.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The response letter is well prepared, and the manuscript is improved according to the comments. So far, I have no further questions about the manuscript. I think that the manuscript is ready for acceptance.

Author Response

Dear Reviewer,

We would like to sincerely thank you for taking the time to review our paper. Your comments and questions are highly valuable and insightful.

Author Response File: Author Response.pdf