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Peer-Review Record

HiXDraw: An Improved XDraw Algorithm Free of Chunk Distortion

Reviewer 1: Wenzhong Shi
Reviewer 2: Anonymous
Reviewer 3: Wanfeng Dou
ISPRS Int. J. Geo-Inf. 2019, 8(3), 153; https://doi.org/10.3390/ijgi8030153
Received: 7 February 2019 / Revised: 3 March 2019 / Accepted: 10 March 2019 / Published: 21 March 2019

Round 1

Reviewer 1 Report

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The manuscript proposed an improved XDraw algorithm by using a new auxiliary grid recording the contributing points at invisible target points. The accuracy and efficiency are verified by the experiments. However, the reviewer has some comments as follow:

1. The full name of LOS should be given as soon as possible at the first appearance.

2. The two criteria for point selection, namely appropriateness and adequacy, should be explained separately for better understanding.

3. The symbols used to record the coordinates of a point should be the same format all the time, namely Pij, where i and j are better use as subscript.

4. According to the manuscript, line 157 “p42 depends on p31 and p30” should be corrected as “p41 depends on p31 and p30”.

5. There is no Figure 9 in the manuscript, therefore the corresponding sentence in line 161 should be rewrited.

6. The line style of R2 and XDraw in Figure 3 are slightly different from its legend. And the name of a figure should be always on the same page with the figure.

7. In a word, there are some format errors in the manuscript need to be correct.


Author Response

Response to Reviewer 1 Comments

 

Dear reviewer,

 

Thanks for your valuable comments and suggestions, which are very helpful in improving the quality of our work. All the comments have been addressed as follows.

 

Point 1: The full name of LOS should be given as soon as possible at the first appearance.

 

Response 1: Thanks for pointing out the issue. We had omitted the first appearance of LOS in the abstract. We have given the full name of LOS at the first appearance.

 

Point 2: The two criteria for point selection, namely appropriateness and adequacy, should be explained separately for better understanding.

 

Response 2: Thanks for your suggestion. We have added the separate explanations of the two criteria in the manuscript.

 

Actual changes: we have deleted the original description, and we have added the following explanations in Section 1.1, page 2, line 46-49:

 

·           Criteria for appropriateness: A point should not make a contribution to calculating the visibility and LOS height if this point is not 4-neighbor adjacent to the LOS.

·           Criteria for adequacy: Every point that is 4-neighbor adjacent to the LOS should contribute to calculating the visibility and LOS height.

 

Point 3: The symbols used to record the coordinates of a point should be the same format all the time, namely Pij, where i and j are better use as subscript.

 

Response 3: Thanks for pointing out the problem. We have unified the format of all the symbols, including those in Figure 1. We record the coordinates of a point using Pij. The i and j are used as subscripts.

 

Point 4: According to the manuscript, line 157 “p42 depends on p31 and p30” should be corrected as “p41 depends on p31 and p30”.

 

Response 4: Thanks for pointing out the problem. We have corrected the mistake by changing “P42” to “P41.

 

Point 5: There is no Figure 9 in the manuscript, therefore the corresponding sentence in line 161 should be rewrited.

 

Response 5: Thanks for pointing out the mistake. The figure that we were referring to is Figure 8. We have replaced “Figure 9” with “Figure 8”. As we have decided to insert other figures into the manuscript, the final number here is 11. All the references of figures in the manuscript have been carefully checked to avoid similar mistakes.

 

Point 6: The line style of R2 and XDraw in Figure 3 are slightly different from its legend. And the name of a figure should be always on the same page with the figure.

 

Response 6: Thanks for pointing out the problems. We have checked the line style of R2 and XDraw in Figure 3 and changed their colors so that they are consistent with the legend. Also, we have increased the space before the figures if necessary to make sure that the name of a figure is on the same page with the figure.

 

Point 7: In a word, there are some format errors in the manuscript need to be correct.

 

Response 7: Thanks for pointing out all these errors. We have revised the format of the manuscript carefully. We have corrected many errors.

 

Actual changes:

We have added the space between “1.2.” and “Viewshed Algorithms” in the title of Section 1.2, and we have added “.” after “1.3” in the title of Section 1.3.

 

We have replaced “Chunk” with “chunk” in line 78 to ensure consistency.

 

We have set the boldface type for “a”, “b”, “c”, and “d” in all the “Figure *(*)” in the manuscript to eliminate inconsistency.

 

We have set the boldface italic type for all the “r” in this manuscript.

 

We have set the italic type for time ratio “η” and error ratio “μ” to eliminate inconsistency.

 


Reviewer 2 Report

Minor issues:

LOS is not defined by line 51.

Bad grammar in the use of verbs along the paper.

Line 50-57 could be better explained with a figure.

Line 59-61 R3 and R2 is not defined.

Line 76-78 the use of "c" or "C" in "chunk distortion"


Major issues. 

This proposal must be rewritten in order to correctly evaluate.


 Subsection 1.1 is a "background" section, however, there are sentences like "the targets always sit on the ground." line 39 that explain more an experimentation constrain. And mix sober state of the art with sentences like "Franklin et al. Proposed two criteria for point selection: " in line 43.


Subsection 1.2 includes several works that must be considered "state of the art" or related work. 


Subsection 1.3 must be a section of "Methods" in which is described the method that must be used in the paper, or in this case improved.


"Chunk distortion" is not clearly detailed until section 3, however, is mentioned along section 1 and 2.


One of the most important changes that must be done until a new revision is rewrite section 4 "Experiments" which is totally mixed with "Results" in one section (This could be done in this way, however "Experiments and Results" section must carry in order)


Another important concern is about "Discussion" section, this section is a big problem to the Originality and Novelty of this proposal, the authors describe that their proposal is the worst performed just claiming that is "still very fast", which is not a qualitative term and must be avoided in a technical paper.


Finally, conclusions again mix two sections, "future work" must be an additional section.


I suggest authors must carefully write again all the paper and try to tackle or justify better the novelty and Scientific Soundness of their proposal.



Author Response

we have uploaded our response as a Word file.

Author Response File: Author Response.docx

Reviewer 3 Report

This article presents an improved XDraw algorithm by considering the effective contributing reference points to compute the visibility of a target. The results of the experiments show the positive support of article's viewpoint. The authors deeply analyzed the problems of chunk distortion on the existing XDraw algorithms and proposed three propositions as the base of algorithm design. However, some modifications are required.

In the last paragraph of page 5,the number of contributing points are required to explain clearly by intuitive figure.

Some errors exist, for example, in the section 3 of page 4 Figure 9(b) and 9(c) do not appear.

In Table 1, the two attributes of each cell are needed to explain further.

Author Response

we have uploaded our response in the word file

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Authors had work hardly to overcome all major issues found in past review, a few minor spelling changes must be done before publishing, however, the proposal could be published in current form.

ISPRS Int. J. Geo-Inf. EISSN 2220-9964 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
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