the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Mapping Three Decades of Urban Growth in China: A 30 m Annual Building Height Dataset (1990–2019)
Abstract. Long-term building height data are critical for analyzing urban morphological evolution and renewal processes, yet such datasets at fine spatial resolutions remain scarce for large geographical regions. This study proposes a framework to generate continuous annual building height maps for China at 30 m spatial resolution from 1990 to 2019, integrating multi-source remote sensing data (Landsat, Sentinel-1/2, et al.) through the eXtreme Gradient Boosting (XGBoost) model. The framework reconstructs Vertical-Vertical (VV) band, incorporates reference data derived from the Continuous Change Detection and Classification (CCDC) algorithm, and utilizes Total Variation (TV) denoising to achieve temporal consistency, while retaining inter-annual building height variations. Validation results demonstrate stable performance of the building height estimates over the past three decades, with nationwide RMSE values ranging between 5.96 and 6.69 m. Comparisons with existing datasets confirm consistency with reference building heights and their temporal evolution driven by urban development and renewal. Furthermore, our dataset shows pronounced horizontal and vertical expansion of Chinese cities between 1990 and 2019, as the total impervious surface area increases from 56,413.68 to 174,320.66 km² and overall building volume rises from 471.24 to 884.69 km³. Provincial contributions to national building volume change substantially over time, with Hebei (12.9 %), Shandong (11.4 %), and Henan (10.3 %) leading in 1990, while Shandong (10.0 %), Guangdong (8.0 %) and Jiangsu (8.0 %) are in the leading positions in 2019. The resulting annual 30 m resolution building height datasets, made openly accessible, provide a valuable foundation for cross-city comparisons, long-term three-dimensional (3D) urban morphology studies, and policy-relevant planning in fast-growing Chinese cities.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Earth System Science Data.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.- Preprint
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Status: final response (author comments only)
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RC1: 'Comment on essd-2025-632', Anonymous Referee #1, 11 Jan 2026
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AC1: 'Reply on RC1', Quanhua Dong, 06 May 2026
We express our deep gratitude for the reviewer’s positive feedback on our work and sincerely appreciate the constructive comments highlighting important areas for improvement regarding data quality, robustness, and validation. Detailed responses are provided in the submitted file “Reply on RC1-submit-20260506.pdf”. In that file, each comment is addressed in detail, with responses organized in a question (black)–response (blue)–revision (red) format to ensure clarity.
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AC1: 'Reply on RC1', Quanhua Dong, 06 May 2026
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RC2: 'Comment on essd-2025-632', Anonymous Referee #2, 16 May 2026
Overall, this is a valuable and timely study. Long-term, annual building-height reconstruction remains an important gap in urban remote sensing, especially at fine spatial resolution and national scale. The proposed dataset has clear potential to support studies of three-dimensional urban growth and renewal in China. Nevertheless, several methodological and interpretive issues still deserve further clarification. Addressing these points would improve the robustness, transparency, and broader usability of the dataset.
- On Page 9, Lines 205–210 and Page 10, Lines 217–219, the manuscript states that reconstructed 1 km VV backscatter is used as an independent variable for XGB-ReVV during 1990–2014. Since this VV layer is reconstructed from Landsat-derived variables and terrain/DSM information, its uncertainty may be propagated into the subsequent 30 m building-height prediction. Although the authors report satisfactory performance of the reconstruction model in the Beijing–Tianjin–Hebei region, it remains unclear whether this performance can be generalized to the whole of China, particularly across regions with different urban forms, climate conditions, and surface characteristics. I suggest that the authors add a short discussion on the robustness and potential error propagation of the reconstructed VV variable, and clarify the extent to which the regional validation supports its nationwide application.
- On Page 7, Lines 148–151, the 2019 reference height data are derived from Baidu Maps building footprints, where floor counts are converted to height using a simple assumption of 3 m per floor. Although this approach is supported by Liu et al. (2021), the cited validation was based on a limited building-height assessment of only 519 buildings in Shenyang, with a reported mean height deviation of approximately 1 m and an accuracy of 86.8%. This raises the question of whether the same level of accuracy can be assumed for nationwide and multi-temporal building-height mapping. In addition, Section 4.1 would benefit from a clearer explanation of how the 2019 reference heights are transferred backward to 1990. In particular, if a pixel experienced in-situ height changes over the past three decades, such as demolition followed by reconstruction of a taller building, it would be helpful to clarify how such cases are handled during annual reference sample generation.
- On Page 9, Lines 195–198, the authors state that applying the 1999 CCDC mask uniformly to 1990–1999 has “negligible effects” on reference data accuracy. However, Page 13, Lines 271–274 show that the validation accuracy of annual reference samples remains only around 65%–70% during 1990–2002. Therefore, I suggest replacing “negligible effects” with a more cautious statement, such as “limited but non-negligible uncertainty may remain for the pre-2000 period.” The authors may also clarify in Section 4.1 or Section 6 that early-year estimates are more suitable for regional-scale or trend-level analyses, rather than for strong interpretation of pixel-level inter-annual changes.
- On Page 10–11, Lines 225–228, the manuscript states that the annual reference height samples are randomly split into 90% training and 10% testing sets. Since both subsets are derived from the same CCDC-filtered and 2019-reference-based sample generation procedure, this evaluation is better interpreted as testing the consistency of model fitting against CCDC-derived reference labels, rather than as a fully independent validation of spatial or temporal generalization. I suggest that the authors make this distinction clearer when presenting the accuracy results, so that the reported RMSE, MAE, and R² are not over-interpreted as completely independent validation metrics.
- Page 16, Lines 335–342 show that latitude and longitude are the most important predictors, even exceeding most optical and SAR variables. Meanwhile, Page 15–16, Lines 318–326 report clear regional discrepancies in model performance, especially poorer performance in parts of southern China and the Pearl River Delta. This suggests that the model may partly rely on regional urban-form priors rather than only pixel-level remote-sensing signals. I recommend that the authors add a short discussion on whether the strong importance of geographic coordinates helps capture spatial heterogeneity, or whether it may introduce risks when extrapolating to regions or cities with limited representation in the training samples.
- Several numerical values should be checked for consistency. The Abstract reports an RMSE range of 5.96–6.69 m, whereas Page 13, Lines 283–284 report 5.94–6.69 m, and Page 29, Lines 490–491 again report 5.96–6.69 m. Similarly, Page 27, Line 460 reports the 2019 national building volume as 884.69 km³, while Page 27, Lines 463–464 report 884.49 km³. I suggest that the authors harmonize these values throughout the manuscript to avoid giving the impression of inconsistent data versions or calculation procedures.
Citation: https://doi.org/10.5194/essd-2025-632-RC2 -
AC2: 'Reply on RC2', Quanhua Dong, 26 May 2026
We would like to express our sincere gratitude to the editor and the reviewers for their valuable time, constructive comments, and thoughtful suggestions on our manuscript. In the supplement PDF, we address each of the reviewer’s points in detail, organizing our responses in a question (black)-response (blue)-original (red) format to ensure clarity.
Data sets
Building Height in China, 1990-2019, 30 m Yizhi Zhang https://doi.org/10.6084/m9.figshare.29918978
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This study develops a time-series 30 m building height dataset for China by integrating multi-source remote sensing data, representing a valuable contribution to large-scale mapping of urban vertical dynamics. The dataset has clear potential for urban studies and related applications. However, several issues related to data quality, robustness, and validation—particularly for high-rise buildings and regions with limited reference data—still need to be carefully addressed to strengthen the reliability and usability of the product. The following comments are provided for the authors’ consideration.
(1) Different building height products adopt different height definitions (e.g., average height, area-weighted average height), and these definitional differences should be explicitly considered. In addition, it is worth noting that some gridded building height products may include only building information, which appears to differ from the definition adopted in this study. As a result, direct resampling and comparison across products may not be strictly comparable.
(2) The reported RMSE of 748.79 m is physically implausible and requires clarification.
(3) Please note that it is unclear whether the same reference building height data were used consistently across Fig. 10b–e. Reference heights above 20 m appear in some panels (b–d) but not in others (e), and zero-height pixels are shown for Ma’s dataset, although such values do not appear in Ma’s original released data.
(4) It is unclear whether this part of the validation is limited to buildings with heights below 45 m.
Overall, Section 4.4 requires careful re-examination.