Pre-disaster mapping with drones: an urban  case study in Victoria, British Columbia, Canada

Kucharczyk, Maja; Hugenholtz, Chris H.

doi:https://doi.org/10.5194/nhess-19-2039-2019

Articles | Volume 19, issue 9

https://doi.org/10.5194/nhess-19-2039-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/nhess-19-2039-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 9

Research article

|

17 Sep 2019

Research article |

| 17 Sep 2019

Pre-disaster mapping with drones: an urban case study in Victoria, British Columbia, Canada

Maja Kucharczyk and Chris H. Hugenholtz

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Final revised paper (published on 17 Sep 2019)
Preprint (discussion started on 26 Nov 2018)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Comments to manuscript: "Pre-disaster mapping with drones: an urban case study in Victoria, BC, Canada"', Anonymous Referee #1, 09 Feb 2019
- AC1: 'Author responses to Referee #1 comments', Maja Kucharczyk, 01 Mar 2019
RC2: 'The use of drones for natural hazards damages evaluation', Anonymous Referee #2, 12 Feb 2019
- AC2: 'Author responses to Referee #2 comments', Maja Kucharczyk, 01 Mar 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (further review by editor and referees) (26 Mar 2019) by Kai Schröter

AR by Maja Kucharczyk on behalf of the Authors (27 Mar 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (28 Mar 2019) by Kai Schröter

RR by Anonymous Referee #1 (10 Apr 2019)

RR by Anonymous Referee #3 (28 Apr 2019)

Suggestions for revision or reasons for rejection

This paper explores the use of a fixed-wing UAV for cityscape mapping and change detections in building shapes. The manuscript has been once revised according to the previous review. The authors demonstrate the use of eBee UAV for the safe and efficient flight over the urbanized area of Victoria, producing an accurate 3D model of buildings. The reviewer carefully read through the revised manuscript and found that the paper is potentially interesting for the readers of the journal NHESS, but also feels that it needs to be further improved to be a scientific paper published in the journal. The major problems correspond to the issues the previous reviewers pointed out in that 1) the applicability of this methodology needs to be further assessed and 2) the organization of the paper needs to be revised.

1. Applicability

The authors addressed this issue, which was raised by the previous reviewers, by adding a paragraph in the discussion on the potential applicability of their methodology in other cases with differing conditions. However, to the reviewer’s point of view, the added description is a bit insufficient and it needs further reconsideration. Although some of the potential differences in the condition for other areas are presented, no word is provided regarding those in legal and local municipal restrictions. However, this is one of the main issues of this study. If the authors emphasize the novelty of this study in performing the UAV flight in the urbanized area of central Victoria, further discussion on the repeatability or applicability of such legal and practical arrangements would be required. The reviewer is aware of some related descriptions of this issue in the other parts of the manuscript, but they could probably be summarized not in a paragraph but as a separate section. The novelty of this study should not be based on the fact of "the first government-approved drone mapping mission over a major Canadian city” (authors’ reply to the reviewer #2 comment) but on the originality of its methodological approach and potential applicabilities.

2. Organization

Related to the above-mentioned issue, the organization of this manuscript seems necessary to be further improved. Although this has been pointed out by the previous reviewer, the authors did not agree with reorganizing their manuscript. However, still, the present reviewer found many portions of the manuscript disorganized, which make it hard for the manuscript to be straightforward. For instance, as noted below, many parts of the discussion could be presented in methods or results. Accordingly, the current result section does not sufficiently represent all the results.

P9 L5-13 These descriptions regarding the LoD should be given in the method and result sections.
P9 L13-15 These are also methods and results.
P9 L15-L18 The LIDAR specification should be presented in methods.
P9 L21-31 The arguments regarding the DoD and LoD sounds valid, but these are mostly results.

Some other comments follow:

P1 L13 Here could be a subsection such as “1.1. Background”, so that the “1.1. Objectives” will be “1.2.”
P7 L26 The explanation of the acronym DoD was already given.
P9 L18-21 Why don’t the authors use their own non-corrected data? It must be possible to generate a dataset without RTK or PPK corrections from their eBee images.
P10 L1-9 It seems OK to insist that the up-to-date datasets are necessary for such a changing urban area. However, why don’t the authors discuss the use of airborne LIDAR itself as the continuous monitoring approach, even if it is costly? As such, the advantage of UAV mapping could be discussed further.

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ED: Reconsider after major revisions (further review by editor and referees) (08 May 2019) by Kai Schröter

AR by Maja Kucharczyk on behalf of the Authors (08 Jun 2019) Author's response Manuscript

ED: Reconsider after major revisions (further review by editor and referees) (25 Jun 2019) by Kai Schröter

ED: Referee Nomination & Report Request started (26 Jun 2019) by Kai Schröter

RR by Anonymous Referee #3 (13 Jul 2019)

ED: Publish as is (30 Jul 2019) by Kai Schröter

AR by Maja Kucharczyk on behalf of the Authors (10 Aug 2019) Manuscript

Short summary

We performed pre-disaster 3-D mapping with a drone in downtown Victoria, BC, Canada. This was the first drone mapping mission over a Canadian city approved by Canada’s aviation authority. We were legally constrained to using a specific drone. The goal was to assess the quality of the 3-D map. Results indicate that the spatial accuracies achieved with this drone would allow for sub-meter building collapse detection, but the non-tilting camera was insufficient for mapping buildings in 3-D.