Identifying the Hierarchical Structure of Nighttime Economic Agglomerations Based on the Fusion of Multisource Data

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study focuses on exploring the economic agglomeration in various districts in Xi’an. A composite index, i.e. QPW index, is constructed by fusing data from multiple sources such as the nighttime lighting data, POI data and Weibo check-in data. A "two-step method" is employed to determine the hotspots of nighttime economic centers, and identify the ranges of various levels of agglomerations. Thus, an approach to identify the hierarchical structure of nighttime economic agglomerations is proposed.

The problem is interesting and the use of multiple data sources to supplement the shortcoming of each data type used is interesting. The following comments are made:

1. The article needs to clarify with supportive contents/citations to assure that the parameter values used are relevant and not random:

   1. Line 179: how is 500m selected?

   2. Lines 192-193: How are the values 0.4 and 0.3 chosen?

   3. Lines 216-219: Provide relevant citations/contents to support the statements made.

   4. Line 239: Here, 50% is assumed as threshold. Is this appropriate for situations such as:

      In a place Place-A, there are two kinds of POIs (e.g. POI-X 51% and POI-Y 49%). If POI-Y is not available in any other places except Place-A, then this assumption will say POI-Y as non-existing.

2. The methodology should be clarified with clear terms and explanations. For example, (lines 198-205 ), what is focus counting? Provide clear explanations to each steps.

3. Line 249 in section 3.1 “The agglomerations are categorized into one to five levels based on the intensity of nighttime economic activities, ranging from high to low, and a spatial distribution map is produced, as shown in Figure 6.”.

   1. What is the significance of each data (NTL, POI, Check-in) in each level defined.

   2. Though the 5 levels are said to be set based on NTL intensity, is there any characteristics which differentiate these levels in reality?

4. Line 361 claims “This complements the bias of a single source of data in the study of agglomerations by combining both nighttime infrastructure and nighttime human activities.” Figure 6 and the explanations in section 3.1 illustrates the results of using fused dataset only. It does not explain the bias involved in using single datasource only ( e.g. using nighttime light only or using POI only or using check-in data only). Please provide some examples of the bias and how they are solved. A comparison of Figure 6 with single data source map would be more clear.

5. The study focuses on fusing multiple datasources such as nighttime lighting and geotagged social media data. Besides, literature should include related past works in this domain such as:

   1. https://isprs-archives.copernicus.org/articles/XLII-2-W7/1341/2017/

   2. https://ieeexplore.ieee.org/document/8506604

   3. https://www.mdpi.com/2071-1050/11/17/4718

   4. https://www.mdpi.com/2072-4292/10/7/1128

   5. https://www.sciencedirect.com/science/article/abs/pii/S0924271618302375

   6. https://doi.org/10.1016/j.compenvurbsys.2021.101749

Considering the observations highlighted above, it is my recommendation that the current study need to address the comments for publication.

Comments on the Quality of English Language

Minor errors such as line 91-92.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This study tries to identify and characterize the hierarchical structure of night-time economic agglomeration by utilizing multi-source data. In general, the topic is interesting. Below please find my comments and suggestions for your consideration.

1. The authors should clearly state their research contribution at the end of the introduction section. What research gaps does this study aim to fill in?

2. I am confused about the relationship between POI and night-time economy. Some categories of POI are not in service during the night.

3. More support is needed for deciding the weight.

4.  Some important and highly relevant studies have not been cited. For example, (1) Huang, B., Zhou, Y., Li, Z., Song, Y., Cai, J., & Tu, W. (2020). Evaluating and characterizing urban vibrancy using spatial big data: Shanghai as a case study. Environment and Planning B: Urban Analytics and City Science, 47(9), 1543–1559. (2) Wang B., Loo B P Y., Liu J*., Lei Y, Zhou L. (Online first) Urban vibrancy and air pollution: avoidance behaviour and built environment. International Journal of Urban Sciences.

5. You are suggested to discuss the limitations of this study and future work directions.

6. Finally, the language should also be further edited.

Comments on the Quality of English Language

Proofreading is needed.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The peer-reviewed article is worthy of publication and has sparked my interest from the outset. However, I am unable to fully assess its scientific value, especially in terms of the research methodology, as I am not an expert in such research procedures. As a researcher of the night-time economy, I will highlight its strengths and weaknesses but I leave the final evaluation to other reviewers and the volume editor:

Among its strengths are:

    Inclusion of digital data in the study of the night-time economy,
    Proposal for the utilization of new data sources,
    Proposal for the application of new research methods,
    Expansion of the geographical scope of research on the night-time economy to Asian countries.

Weaknesses include:

    Lack of reference to the geographical context. Readers outside of China are unaware of the specificity of the night-time economy, which may lead to a misinterpretation of the presented results.
    The authors did not demonstrate a broad understanding of night-time economy issues; the literature review needs to be expanded.
    The assumption that light (its intensity) can be important information about the night-time economy is accepted. However, the authors failed to indicate research limitations in this regard. The work does not even signal that a significant portion of the night-time economy is indoor and paradoxically does not generate external light, and even prefers semi-darkness.
    The concluding part of the work is very weak - lack of comparisons, lack of references to international literature.
    My main criticism is the lack of reflection on the social costs of night-time economy development. Reading this work might give the impression that maximizing night-time economy development is advisable, which is absurd. The night-time economy generates enormous social costs, and these should be addressed. The authors' argument that they only examined the spatial distribution of activities at a given moment in time does not justify the lack of awareness of the various aspects of the phenomenon being studied, undermining contemporary research.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

- Provide citations to concepts like ArcGIS( line 253).
- Regarding Figure 7, please label each of the four images properly.

Comments on the Quality of English Language

It is appropriate to use "Figure" instead of "Fig. " while referencing figures within the content. Please refer author guidelines.

Author Response

We are very grateful for your constructive comments and suggestions for our manuscript！In the following, the responses to all the comments are provided one by one.Our changes/additions to the re-submitted files are given in the highlight text.

1.Relevant references have been cited in the paper（line 253,677）：ESRI. ArcGIS desktop and spatial analyst extension: release 10.5. Redlands: Environmental Systems Research Institute. 2017.

2.Thanks to your suggestion, we have re-labeled and re-captioned Figure 7(line 378-380)

3. Thanks for the heads up, all "Fig." have been replaced with "Figure".

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have well addressed my comments.

Author Response

Thank you for your guidance suggestions as well as your approval of the article!

Reviewer 3 Report

Comments and Suggestions for Authors

The authors responded to my comments. From the perspective of studies on the night-time economy, the article is embedded in the issue of the functioning of the city at night and introduces new methodological perspectives.

Author Response

Thank you for your guidance suggestions as well as your approval of the article!