Crop Mapping Based on Historical Samples and New Training Samples Generation in Heilongjiang Province, China
, Diyou Liu 1,2, Quan Xiong 1,2, Ning Yang 1,2, Tianwei Ren 1,2, Chao Zhang 1,2, Xiaodong Zhang 1,2 and Shaoming Li 1,2Round 1
Reviewer 1 Report
It is important to map the inter-annual crop change pattern for agricultural production regulation, especially under the present global climate change scenario. However, such efforts are highly challenging due to the time consumed for collecting field information. The present study makes use of new training samples generated from historical data and spatial information gathered from the 2018 season (mainly vegetation related indexes) to map the crop type of the present season. I only have a few minor issues with regard to the paper.
I found several faulty sentence formations and grammatical errors throughout the manuscript. I have listed a few below, but make sure that the manuscript gets evaluated by a native speaker. Title – Would this be better ? “Crop mapping based on historical samples and new training samples generation in Heilongjiang Province, China”
LL 17 -19 – You mention current season here. You should mention the year in the first use. Otherwise, the readers might think it is 2019.
LL 23-24- Better merge the information of the next sentence in this sentence. “Large number of samples” is vague.
LL 31-36- This sentence should be rewritten as there are grammatical errors and is too long.
LL 56-57- You mention about three methods here. You could have possibly compared the accuracy of the three methods to your methods, and then probably discussed why your method is more advantageous than the other methods.
LL 65-67- This sentence is too confusing to read. Rewrite and give references.
LL 79-81 – Rewrite this sentence to remove grammatical errors and reading comprehensibility
LL 115-116- Explain specifically what is GF1 here. Everyone won’t know it is remotely sensed satellite data. Be more specific here.
LL 117-118- Rewrite this sentence to remove grammatical errors and reading comprehensibility
L 121- You say lack of seasonal data. The seasonal range of your study is probably less as the crops are only grown 6 months in a year. Also, there is no seasonal shifting of crops. So probably say monthly?
LL 124-125- Rewrite this sentence to remove grammatical errors (were instead of are). Also, mention the country here.
L 128 – Give the reference for the climate here and for the next study area.
L 146- “ With less interference”. What do you mean here?
L 147- I don’t see much differences between the two regions selected for this study with regard to the climate and cropping patterns. How can you substantiate your statement about comparing regional differences?
152-153 – This sentence is not clear. Rewrite
L 155- Why didn’t you use 8 m data instead of 16 m? I feel it would have probably increased the accuracy.
L 158 – Cloud amount? Rewrite?
L 172- Mention the model of the GPS used
L 295- How much of the verification samples lied within the historical samples that did not undergo any change? How did you ensure the randomization of data, bias and the historical data did not affect your accuracy assessment?
Author Response
Dear reviewer,
Please see the attachment. Thank you!
Author Response File: 
Author Response.docx
Reviewer 2 Report
In this manuscript authors present a method to create crop maps using historical samples. In my opinion, although authors have worked in an interesting area, in my opinion, they have selected an study area quite easy or they converted easy because they took into account a single legend.
Please remove sample size in abstract section. In addition, it is confused line 24-29.
Line 47: Please include references for "crop classification studies".
Line 52: "tedious", it does not sound good.
Line 58-59: What about crops with similar cycling?
Please, include Coordinate reference system in lines 127 and 131.
Line 139-143: Just only two crops?
Line 172: Include GPS model device.
Line 174-176: Any criteria to know if this sample size is adequate?
Figure 2: I understand the criteria of economy in the project but if you only sample near communication channels you are introducing a bias in your validation. In addition, there are areas in the study area that do not have any control.
Section 3.1 Provide more information about image processing.
Line 205: replace "6-s model" by "6-S radiative transfer model". In addition, where did you get values to generate the model, I mean values like ozone aerosol,...
Line 227: I do not understand "weak correlation coefficients" in this sentence.
Line 235: replace "blue bands" by "blue spectral bands".
Figure 4: Which year is figure data? Is it possible to include the other crops?
Section 3.6 What is sample size to validate?
Table 4. "Using sample of 2018" Your sample to "other crops" is higher than rice. Moreover, Rice has a low accuracy. On the other hand "Using sample of historical data" confused other crops with maize.
Discussion section is not a real discussion, please rewrite it.
Author Response
Dear reviewer,
Please see the attachment. Thank you!
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Authors have taken into account my comments.
Manuscript is able to be published.
