Assessing the Quality of the Leica BLK2GO Mobile Laser Scanner versus the Focus 3D S120 Static Terrestrial Laser Scanner for a Preliminary Study of Garden Digital Surveying
Round 1
Reviewer 1 Report
The authors present a case study of documenting a garden using static laser scanning and mobile laser scanning in Lisbon. Although the topic itself is very interesting, the paper is rather descriptive and the methodological and geometrical rationale is not sufficiently described. A quality assessment is mentioned in the title of the manuscript, but the analysis is limited to a rather qualitative comparison. Geometrical information about the comparison is missing in the body, as well as in the conclusion. A comparison of the various tree stem diameters or the evaluation of the deviation between the sensors (e.g., as a function of surface properties, like roughness) would be useful. In terms of comparison of the used equipment, neither the accuracy parameters nor the effect on these parameters is not presented. Some advantages of laser scanning are presented in the introduction, but the relation between these advantages and the characteristics of the study area is not made. Lastly, the evaluation of the results at the end of the paper is very descriptive, and no conclusions can be drawn regarding the repeatability of the technique.
As mentioned earlier, the topic is very interesting, and the paper is properly written from a linguistic perspective. To date, many theoretical and case-study-based papers are written about the comparison of photogrammetry versus laser scanning on the one hand, and static versus kinematic laser scanning on the other hand. It is advised to have a closer look at the literature for the development of a sound qualitative and quantitative analysis of these different methods. These methods can certainly be implemented for the documentation of the park presented in the manuscript. Unfortunately, I cannot recommend the publication of this paper in its current form.
Author Response
Dear reviewer,
thank you for your valuable comments.
We have followed your suggestions and made some changes to the text, starting with the title of the article.
We have improved the analysis, as you can see. The parts in yellow are those we have added/changed.
New references have been added to the text for a clear description of the state of the art and the research objective.
Unfortunately, due to the Christmas holidays, we had limited access to our workstations and we hope for a second round of reviewing to further improve our article. There are some details on tree diameters that we would like to present better next time, as well as improve some parts of the discussion section.
Thank you again for your help.
GDD
Reviewer 2 Report
The paper presents preliminary results of a study on latest technology for gardens.
The authors discuss the use of TLS and MLS for garden surveying. The field of application is certainly interesting, but the methods adopted and their comparison are sometimes described in a superficial way.
It is necessary to integrate references to better place the research carried out. The conclusions should also be argued in more depth
Author Response
Dear reviewer,
thank you for your valuable comments.
We have followed your suggestions and made some changes to the text, starting with the title of the article.
We have improved the analysis, as you can see. The parts in yellow are those we have added/changed.
New references have been added to the text for a clear description of the state of the art and the research objective.
Unfortunately, due to the Christmas holidays, we had limited access to our workstations and we hope for a second round of reviewing to further improve our article. There are some details on tree diameters that we would like to present better next time, as well as improve some parts of the discussion section.
Thank you again for your help.
GDD
Reviewer 3 Report
The article discusses the feasibility and productivity of 3D scanning of an area of historic forest, and assesses the efficacy of producing a 3D pointcloud. It proceeds to compare and assess the measurements according to a series of parameters: breast height diameter, contour lines etc.
It is restricted to the use of 2 sensors only, of which only one was operated by the authors themselves. The authors did the data processing. The processing steps in CloudCompare are described clearly and reproducibly.
The article is well structured, but requires more definition of details regarding sensors specifications and generally embedding it into a current the state-of-the-art. The conclusion needs to reflect on other sensors on the market to give a correct picture of the possibilities of SLAM sensors. In addition, the requirements of historic gardens including architectural and decorative features for the examination of art-historical or architectural features, in contrast to requirements of forestry to care for the plants need to be more clearly presented. Which are the classical traditional methods used by forestry and why can they not be complemented rather than replaced with 3D imaging?
The data recording and data processing mechanisms and technologies are well known and well established. This is a project report, and does not represent novel or original research.
Detailed remarks:
Abstract: line 13-18 - > do not condemn the "traditional and classical methods" , this is too negative and also not applicable,
Grammar: line 24 - remove "more".
Grammar line 55: "the use of laser scanners today makes possible" -> Today's use of 3d laser scanning makes it possible to ....
English Grammar Line 245: "to better construct" move the adverb before the verb
Line 76: please insert forward reference to your own section 2.1.1. , otherwise, it seems at first glance that you are completely missing the technical description of the sensors.
line 88: 3D scanning does not directly produce a "virtual environment"! This would be a more intricate long process of implementing and compiling a VR environment. All it does is to produce a 3D digital geospatial dataset in the first place! please exchange this wording in two places in your paper.
Recommendation: replace "machine" with "sensor" throughout the text.
The following considerations are missing from the text:
Name the Charta of Florence (with complete title!) already in the introduction or in the section 2 - not only at the end. What are the challenges today, and how does UNESCO deal with climate change regarding historic gardens. Add recent references.
2.1.1. clear references regarding scanner specifications (cite spec sheet with date, model number and reference it later) , add scanner recording principles for each scanner in this section, for example Phase-shift method for Faro , in more detail.
Figures 2,3,4 : scalebar is missing. Please insert a Grid (for example 10m or 20m grid) and scalebar.
line 59: traditional technique - specify the techniques that you refer to: are these drawing, total station measurement, aerial photography etc etc... this is too vague and does not allow an assessment against requirements in forestry for the care of historically planted gardens
Line 208: who defines the threshold of 40mm and why?
The final assessment is missing the comparison with other more potent SLAM sensors on the market. Of course the Lidar scanners , for example of an in-built Velodyne 3D scanner (in a Geoslam Horizon or Pegasus backpack by Leica Geosystems) can do 3D scanning in complete darkness, because they are based on LiDaR! Your remark in line 421 is wrong or only applicable to the BLK2GO. Your assessment in line 413 is also wrong as it only applies to BLK2GO. Other SLAM systems have a reach up to 100m.
Please do a majour revision of the paper based on the comments.
Author Response
Dear reviewer,
thank you for your valuable comments.
We have followed your suggestions and made some changes to the text, starting with the title of the article.
We have improved the analysis, as you can see. The parts in yellow are those we have added/changed.
New references have been added to the text for a clear description of the state of the art and the research objective.
Unfortunately, due to the Christmas holidays, we had limited access to our workstations and we hope for a second round of reviewing to further improve our article. There are some details on tree diameters that we would like to present better next time, as well as improve some parts of the discussion section.
Thank you again for your help.
GDD
Reviewer 4 Report
The article compares the processes and raw registered point clouds of TLS and MLS technologies for documenting forest areas.
The goal is clear. The methods are clearly described. The conclusions are confirmed by the presented results.
There are several points in the text that require attention:
Line 164 - information is given on the complete data for BLK2GO (total number of points and total file size), but this information is not available for the FARO scanner. Further in the text, the data for both scanners for the analysis zone are given. But at this point, this information should be removed or supplemented with the same information for the FARO scanner.
Line 187 - typo "rage".
Figure 1 - the numbers on the map do not help to find a place, but on the contrary, they are very confusing. They should be removed. Leave on the map only a marker for the location of the work area and a description of the location.
Figure 2, 3, 4, 5 - you need to specify the scale.
Figures 8 and 9 are desirable to indicate the scale.
The article should be accepted for publication with minor changes.
Author Response
Dear reviewer,
thank you for your valuable comments.
We have followed your suggestions and made some changes to the text, starting with the title of the article.
We have improved the analysis, as you can see. The parts in yellow are those we have added/changed.
New references have been added to the text for a clear description of the state of the art and the research objective.
Unfortunately, due to the Christmas holidays, we had limited access to our workstations and we hope for a second round of reviewing to further improve our article. There are some details on tree diameters that we would like to present better next time, as well as improve some parts of the discussion section.
Thank you again for your help.
GDD
Round 2
Reviewer 3 Report
Dear authors, (yes MDPI seems to make us work during the winter break - :) , happy to have a further round of a review including new images when you are back at your desks at your institution) .
First of all : very well done for the improvement of the paper, inserting new extended text and new very relevant references. This has massively improved the quality of the article from my point of view.
For now, I have only very small remarks:
Line 87 - reference 7 is double
Line 216 - under "our" supervision?
Line 588 : technology (spelling)
Line 646: December (not Dicember)
Line 718: possibly add date of accession of sources and date of publication if known (and possibly titel of document if specific)
Queries on images:
Figure 7b and Figure 4b: please consider if it would be more informative to contrict the maximum and minimum display of the graph to a smaller range (yes, Ignoring the small amount of outliers), so that we can see the distribution better? for example in 7b from -0,3 to +0,3 on the x-axis, and in Figure 4b only up to +0,8? (CC has an option to recalculate the graph display to cut off the outliers)
Looking forward to the next round. Congrats and have a good passage to the new year!
Author Response
Thanks again for your valuable feedback.
The typos listed in your report have been corrected.
Unfortunately, my version of CC doesn't allow me to scale the graphics in Figure 7b and Figure 4b, but I will check if I can find a solution for that and will ask to replace the images to the journal before the final publication.
Regarding the body text, I have further improved the article and added paragraph 3.1.4
