Analysing Temporal Evolution of OpenStreetMap Waterways Completeness in a Mountain Region of Portugal

1. Summary

The authors thanks to the reviewer_1 the comments and suggestions that will contributes to improve the manuscript.

Comment 1: It requires moderate English improvement and technical proofreading.

The authors agree with this comment and thank that suggestion. The revised version of the manuscript presents improvement on English, particularly in grammar and some type of specific vocabulary.

Comment 2: The manuscript does not present innovative algorithmic methods or extensive analysis, limiting its contribution.

The authors agree with the comment and thank the suggestions, however as we mentioned in manuscript, there exist few bibliographic references to this topic (completeness of watercourses), then we decide to draw the idea in this format, although in further investigations we may introduce those methods and expand the analysis.

Comment 3: Issues with the methodological Rigor and Insufficient detail in analysing altitude, slope, and proximity to settlements.

The authors agree with the comment and thank the suggestions. As can be seen in revised version, the authors improve the analysis of the relations between those factors (indicators) with the evolution of completeness of OSM watercourses.

Comment 4: The conclusion is not strong and does not effectively summarize the findings or the impact of various attributes on completeness.

The authors agree with the comment and thank the suggestions. The conclusions were improved, and the authors tried to describe them in a more comprehensive way, presenting some possible justifications for some results, such as the indicators related to land use (rock and vegetation).

Once again, the authors want to thank you for taking the time to review this manuscript. Please find the detailed responses and revisions/corrections highlighted/in track changes in the manuscript re-submitted file.

1. Summary

The authors thanks to the reviewer_2 the comments and suggestions that will contributes to improve the manuscript.

Comment 1: The innovation and motivation should be indicated in the section ABSTRACT and the last paragraph of section INTRODUCTION.

The authors agree with these comments and thank that suggestion. Thus, the revised manuscript includes an improvement of abstract where the authors summarize in a clearly way what had been done with this study. The last paragraph of Introduction chapter was also improved and developed.

Comment 2: As we all know, OSM is voluntary geographic information, and how ensure the reliability and accuracy of OSM waterways data?

The authors thank the question, however accuracy (planimetric or altimetric) of OSM waterways is not the topic of the study. However, in a further study we may consider extending more quality elements, such as accuracy of OSM watercourses.

Comment 3: Is OSM waterways data the same scale as the reference data? Does it affect the results of the study? That should be discussed.

The authors want to thank your questions that we consider relevant in this theme scope. However, the objective of this study it wasn’t to analyse accuracy (planimetric or altimetric) of OSM waterways but the completeness of those watercourses. The OSM waterways are not at the same scale of reference data (official hydrography at 1/25 000), but that is not a problem because the scale of digitalization by volunteers depends on the spatial resolution of satellite image used. We also know that this type of feature “waterway” occupied significative extension of terrain, whereby reference data at 1/25 000 scale it is enough to evaluate the completeness. Furthermore, all the lines (OSM and reference) are compared in the same projected reference system (PT-TM06/ETRS89). We also consider the results are influenced by the fact that they aren’t at the same scale, however, this type of data has a pre-processing completely distinct.

Comment 4: In addition to the reference data provided by Army Geospatial Information Center Hydrography, it is recommended that major waterway be selected and evaluated using the results obtained from remote sensing images with high-spatial resolution.

The authors thank the suggestion; however, they think that the reference data used in the study (official military hydrography of 1/25 000 scale) is enough data to evaluate the completeness of OSM waterways. But the authors may will consider doing that analysis in further developments of this topic.

The authors want to thank you for taking the time to review this manuscript. Please find the detailed responses and revisions/corrections highlighted/in track changes in the manuscript re-submitted file.

1. Summary

The authors thanks and recognize the important comments and suggestions sending by reviewer_3 that will contributes to improve the manuscript

Comment 1: In the Abstract Section, authors need write research methods such as what kind of the model or what kind of the image.

The authors agree with this comment and thank that suggestion. This suggestion was included in abstract (revised version).

Comment 2:  Line 23-23, in the Abstract Section, “Regarding the indicator’s altitude, slope and location/proximity of settlements, it was not possible to observe their influence on the evolution of the completeness of this geographic entity”. Also in the Line 292-294 of Conclusions Section, “We concluded that the slope is not related to the representation of the news’s OSM watercourses, as most of them are in the lower slope areas.”

In general, actually it is indeed the influence factors for the geographic distribution of waterways from the geography view or based on geography knowledge. For example, most of watercourses are in the lower slope areas which is just the relationship or results the altitude, slope and watercourses interact. But authors put forward the idea above on the Line 23-23 and Line 292-294. So, it is necessary for authors to indepth explain for this.

The authors thank this observation and suggestion. In revised version of manuscript some explanations were done about these issues. These both indicators (altitude and slope) contribute to define the geometric of watercourses and is the relief that define the way of water in land surface. In our study area there exist a main river (Mondego River) in in regions of lower altitude. But even being the region of lower altitude correspond also to highest slope. In this way, in this specific zone both indicators have the contrary extreme values. On the other hand, we remind that those descriptions about OSM watercourses were made about news (the ones that were extracted on 2023 from OSM platform).

Comment 3: Line 104-105, in the Materials and Methods Section, authors should list the download netaddress, i.e. uniform resource locator of OpenStreetMap waterways. At Line 129, authors should list the radius of Z1 and Z2. Considering the accuracy of OpenStreetMap waterways comparing with the Reference data from Army Geospatial Information Center Hydrography, quantitative model for the accuracy of calculation should be list in Materials and Methods Section so that the accuracy of OpenStreetMap waterways can be verified.

The authors thank your comments and suggestions. The radius of Z1 and Z2 circles were included in the revised manuscript version. About the other part of comments, we remind that the analysis performed were about completeness of OSM watercourses not about the accuracy. The visual interpretation over satellite image was a way (method) used to perform some of them (analysis).

Comment 4: Figure 1 lacks north arrow and scale bar. In Figure 2, rivers (main stream) and anabranch (stream) should be drawn with different chickness for identifying them easily.

The authors thank the comments and suggestions. The Figure 1 was improved with the suggestions. But about the Figure 2, the authors didn’t understand effectively the suggestion.

Comment 5: In Figure 7, the letters like “PT-TM06/ETRS 89” and “Value” can be deleted. In Figure 8, the letters like “<VALUE>” can be deleted. Also, in this Figure 8, slope classes can be breaked off at the integer division by the manual way in ArcGIS software. In addition, existing colour bar in ArcGIS for the elevation can be used for DEM in Figure 8.

The authors thank the comments and suggestions. The Figure 8 was revise taking account the suggestions.

Comment 6: Line 181-183, in the Results Analysis and Discussion Section, “When we observe the news’s OSM watercourses, we see that they are mainly located in lower altitude areas.” Hopefully authors can explain this point. Similarly, authors can explain why or give some reasons for the sentences at Line 194-196 “it can be observed that some small watercourses also appearing in areas with steeper slopes.” and the sentences at Line 214-217.

The authors thank the comments and suggestions. In this stage we are analysing the news’s OSM waterways in all study area. And we observe that in a global form the new lines are in lower altitude areas, but the also exist an area with steeper slopes and higher altitude where exist news’s waterways.

Comment 7:  Line 271-272, Figure 7 and Figure 8 both lacks of the scale bar in the maps. And it is better for authors can vectorize or label some settlements in the two maps because settlements is mentioned in this Section.

The authors thank the comments and suggestions. The corrections suggested were performed and may be seen in the revised manuscript. The Figure 9 was replaced and some part of settlement was vectorized above satellite image.

Comment 8: Line 159, “such us” might be “such as”, so please check it.

The authors thank the corrections. The authors do that correction.

Once again, the authors want to thank you for taking the time to review this manuscript. Please find the detailed responses and revisions/corrections highlighted/in track changes in the manuscript re-submitted file.

1. Summary

The authors thanks and recognize the important comments and suggestions sending by reviewer_4 that will contributes to improve the manuscript

Comment 1: The main one is that the authors have duplicated their analyses. They analyzed OSM data over a 1:25K map (M888 - 201) and then randomly selected two smaller areas, on the same map, to do the same analyses. This is pointless.

The authors thank your comments and suggestions, although they consider important to clarify that when both zones were defined to analyzed if there exist any tendency of completeness evolution in some regions (zones) within the study area. We consider this relevant in this particularly type of geospatial opensourse information.

Comment 2: Authors’ objectives, as described, constitute the second problem of this manuscript. Despite all the literature, the authors chose to carry out their assessment over an isolated and sparsely populated area. Anyone familiar with literature would expect little or no change in such an area, especially with such a map feature (i.e., watercourses). Therefore, most readers might question the choice of such an area to assess the completeness of OSM data. The answer may lie in the future direction of authors’ research. They aim to repeat the analysis over another region type to verify the relationship between OSM data completeness and the presence of people nearby, as demonstrated by the literature for other map feature types. Such an objective is legitimate. However, without proper explanations in the introduction, the reader may only wonder about the authors’ objectives and the quality of their work.

The authors thank your comments and suggestions. We understand the reasons of that comments, but the feature analyzed in this study is “waterway” that have particularly treatment in process of creation in OSM platform. The big rivers normally across extent rural areas, and we already know that most of published works about completeness of OSM data are related to objects located in urban environment, we even thought that it was an advantage – exploring the completeness of a feature OSM that few authors had did.

Once again, the authors want to thank you for taking the time to review this manuscript. Please find the detailed responses and revisions/corrections highlighted/in track changes in the manuscript re-submitted file.