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CadastreVision: A benchmark dataset for cadastral boundary delineation from multi-resolution earth observation images CadastreVision:根据多分辨率地球观测图像划分地籍边界的基准数据集
IF 10.6 1区 地球科学 Q1 GEOGRAPHY, PHYSICAL Pub Date : 2024-08-24 DOI: 10.1016/j.isprsjprs.2024.08.005

Approximately 70%–75% of people worldwide have no formally registered land rights. Fit-For-Purpose Land Administration was introduced to address this problem and focuses on delineating visible cadastral boundaries from earth observation imagery. Recent studies have shown the potential of deep learning models to extract these visible cadastral boundaries automatically. However, studies are limited by the small size and geographical coverage of available datasets and by the lack of information about which cadastral boundaries are visible, i.e., associated with a physical object boundary. To overcome these problems, we present CadastreVision, a benchmark dataset containing cadastral reference data and corresponding multi-resolution earth observation imagery from The Netherlands, with a spatial resolution ranging from 0.1 m to 10 m. The ratio between visible and non-visible cadastral boundaries is essential to evaluate the potential automation level in cadastral boundary extraction from earth observation images and interpret results obtained by deep learning models. We investigate this ratio using a novel analysis pipeline that overlays cadastral reference data with visible topographic object boundaries. Our results show that approximately 72% of the total length of cadastral boundaries in The Netherlands are visible. CadastreVision will enable new developments in cadastral boundary delineation and future endeavours to investigate knowledge transfer to data-scarce areas. Our data and code is available at https://github.com/jeroengrift/cadastrevision.

全世界约有 70%-75% 的人没有正式登记的土地权。为解决这一问题,推出了 "合目的土地管理",其重点是从地球观测图像中划定可见的地籍边界。最近的研究表明,深度学习模型具有自动提取这些可见地籍边界的潜力。然而,由于可用数据集的规模较小、地理覆盖面较窄,而且缺乏关于哪些地籍边界是可见的(即与物理对象边界相关联)的信息,这些研究受到了限制。为了克服这些问题,我们提出了一个基准数据集,其中包含地籍参考数据和荷兰相应的多分辨率地球观测图像,空间分辨率从 0.1 米到 10 米不等。可见和非可见地籍边界之间的比例对于评估从地球观测图像中提取地籍边界的潜在自动化水平以及解释深度学习模型获得的结果至关重要。我们使用一个新颖的分析管道来研究这一比例,该管道将地籍参考数据与可见地形物体边界重叠。我们的结果表明,荷兰地籍边界总长度的约 72% 是可见的,这将促进地籍边界划分的新发展,并有助于未来研究向数据稀缺地区转移知识的工作。我们的数据和代码可在以下网址获取
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引用次数: 0
Graph-based adaptive weighted fusion SLAM using multimodal data in complex underground spaces 在复杂地下空间使用多模态数据的基于图的自适应加权融合 SLAM
IF 10.6 1区 地球科学 Q1 GEOGRAPHY, PHYSICAL Pub Date : 2024-08-24 DOI: 10.1016/j.isprsjprs.2024.08.007

Accurate and robust simultaneous localization and mapping (SLAM) is essential for autonomous exploration, unmanned transportation, and emergency rescue operations in complex underground spaces. However, the demanding conditions of underground spaces, characterized by poor lighting, weak textures, and high dust levels, pose substantial challenges to SLAM. To address this issue, we propose a graph-based adaptive weighted fusion SLAM (AWF-SLAM) for autonomous robots to achieve accurate and robust SLAM in complex underground spaces. First, a contrast limited adaptive histogram equalization (CLAHE) that combined adaptive gamma correction with weighting distribution (AGCWD) in hue, saturation, and value (HSV) space is proposed to enhance the brightness and contrast of visual images in underground spaces. Then, the performance of each sensor is evaluated using a consistency check based on the Mahalanobis distance to select the optimal configuration for specific conditions. Subsequently, we elaborate an adaptive weighting function model, which leverages the residuals from point cloud matching and the inner point rate of image matching. This model fuses data from light detection and ranging (LiDAR), inertial measurement unit (IMU), and cameras dynamically, enhancing the flexibility of the fusion process. Finally, multiple primitive features are adaptively fused within the factor graph optimization, utilizing a sliding window approach. Extensive experiments were conducted to check the performance of AWF-SLAM using a self-designed mobile robot in underground parking lots, excavated subway tunnels, and complex underground coal mine spaces based on reference trajectories and reconstructions provided by state-of-the-art methods. Satisfactorily, the root mean square error (RMSE) of trajectory translation is only 0.17 m, and the mean relative robustness distance between the point cloud maps reconstructed by AWF-SLAM and the reference point cloud map is lower than 0.09 m. These results indicate a substantial improvement in the accuracy and robustness of SLAM in complex underground spaces.

在复杂的地下空间进行自主探索、无人驾驶运输和紧急救援行动时,准确而稳健的同步定位和绘图(SLAM)是必不可少的。然而,地下空间光照差、纹理弱、灰尘大,这些苛刻的条件给 SLAM 带来了巨大挑战。为了解决这个问题,我们提出了一种基于图的自适应加权融合 SLAM(AWF-SLAM),用于自主机器人在复杂的地下空间实现精确、稳健的 SLAM。首先,我们提出了一种对比度受限的自适应直方图均衡(CLAHE),它结合了色调、饱和度和值(HSV)空间的自适应伽玛校正与加权分布(AGCWD),以增强地下空间视觉图像的亮度和对比度。然后,利用基于 Mahalanobis 距离的一致性检查来评估每个传感器的性能,从而为特定条件选择最佳配置。随后,我们阐述了一个自适应加权函数模型,该模型利用了点云匹配的残差和图像匹配的内点率。该模型可动态融合来自光探测与测距(LiDAR)、惯性测量单元(IMU)和摄像头的数据,从而提高融合过程的灵活性。最后,利用滑动窗口方法,在因子图优化范围内对多个原始特征进行自适应融合。基于最先进方法提供的参考轨迹和重构,使用自行设计的移动机器人在地下停车场、挖掘的地铁隧道和复杂的地下煤矿空间进行了广泛的实验,以检验 AWF-SLAM 的性能。令人满意的是,轨迹平移的均方根误差(RMSE)仅为 0.17 m,AWF-SLAM 重建的点云图与参考点云图之间的平均相对鲁棒性距离低于 0.09 m。
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引用次数: 0
UB-FineNet: Urban building fine-grained classification network for open-access satellite images UB-FineNet:用于开放获取卫星图像的城市建筑细粒度分类网络
IF 10.6 1区 地球科学 Q1 GEOGRAPHY, PHYSICAL Pub Date : 2024-08-23 DOI: 10.1016/j.isprsjprs.2024.08.008

Fine classification of city-scale buildings using satellite imagery is a crucial research area with significant implications for urban planning, infrastructure development, and population distribution analysis. However, the task faces great challenges due to low-resolution overhead images acquired from high-altitude space-borne platforms and the long-tailed sample distribution of fine-grained urban building categories, leading to a severe class imbalance problem. To address these issues, we propose a deep network approach to the fine-grained classification of urban buildings using open-access satellite images. A Denoising Diffusion Probabilistic Model (DDPM) based super-resolution method is first introduced to enhance the spatial resolution of satellite images, which benefits from domain-adaptive knowledge distillation. Then, a new fine-grained classification network with Category Information Balancing Module (CIBM) and Contrastive Supervision (CS) technique is proposed to mitigate the problem of class imbalance and improve the classification robustness and accuracy. Experiments on Hong Kong data set with 11 distinct building types revealed promising classification results with a mean Top-1 accuracy of 60.45%, which is on par with street-view image based approaches. A comprehensive ablation study demonstrates that the CIBM and CS modules improve Top-1 accuracy by 2.6% and 3.5%, respectively, over the baseline approach. In addition, these modules can be easily integrated into other classification networks, achieving similar performance improvements. This research advances urban analysis by providing an effective solution for detailed classification of buildings in complex mega-city environments using only open-access satellite imagery. The proposed technique can serve as a valuable tool for urban planners, aiding in the understanding of economic, industrial, and population distribution within cities and regions, ultimately facilitating informed decision-making in urban development and infrastructure planning. Data and code will be publicly available at https://github.com/ZhiyiHe1997/UB-FineNet.

利用卫星图像对城市规模的建筑物进行精细分类是一个重要的研究领域,对城市规划、基础设施建设和人口分布分析具有重大意义。然而,由于高空机载平台获取的俯拍图像分辨率低,城市建筑细粒度分类的样本分布呈长尾状,导致严重的类不平衡问题,因此这项任务面临巨大挑战。为了解决这些问题,我们提出了一种利用开放获取的卫星图像对城市建筑进行细粒度分类的深度网络方法。我们首先引入了基于去噪扩散概率模型(DDPM)的超分辨率方法来提高卫星图像的空间分辨率,这种方法得益于领域自适应知识提炼。然后,利用类别信息平衡模块(CIBM)和对比监督(CS)技术提出了一种新的细粒度分类网络,以缓解类别不平衡问题,提高分类的鲁棒性和准确性。在包含 11 种不同建筑类型的香港数据集上进行的实验表明,分类结果很有前途,Top-1 的平均准确率为 60.45%,与基于街景图像的方法相当。一项全面的消融研究表明,与基线方法相比,CIBM 和 CS 模块的 Top-1 准确率分别提高了 2.6% 和 3.5%。此外,这些模块还可以轻松集成到其他分类网络中,实现类似的性能改进。这项研究为仅使用开放获取的卫星图像对复杂特大城市环境中的建筑物进行详细分类提供了有效的解决方案,从而推进了城市分析。所提出的技术可作为城市规划者的宝贵工具,帮助了解城市和区域内的经济、工业和人口分布情况,最终促进城市发展和基础设施规划方面的明智决策。数据和代码将在以下网址公开发布
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引用次数: 0
Integrating geographic knowledge into deep learning for spatiotemporal local climate zone mapping derived thermal environment exploration across Chinese climate zones 将地理知识融入深度学习,绘制时空局部气候区图,探索中国各气候区的热环境
IF 10.6 1区 地球科学 Q1 GEOGRAPHY, PHYSICAL Pub Date : 2024-08-21 DOI: 10.1016/j.isprsjprs.2024.08.004

The Local Climate Zone (LCZ) scheme representing urban structure and land use pattern is essential for urban heat island (UHI) research. Fine-grained LCZ mapping considering spatial and temporal heterogeneity can provide a more precise characterization of surface thermal properties, thereby enabling a comprehensive analysis and understanding of spatiotemporal trends in climate change research. However, data-driven deep learning-based methods have limitations in coping with the complex urban landscapes of the real-world scenarios, including the spectral similarity of different LCZ and the geospatial heterogeneity of urban LCZ categories. In this study, we constructed a geographic knowledge base for enhanced LCZ characterization with the consideration of prior surface spatial information, including a set of spectral indices and urban morphological parameters (UMPs). Then, we integrated the explicable geographic knowledge base into a learnable deep learning framework in an end-to-end manner for accurate LCZ mapping by fusing multi-source heterogeneous data with a multi-level fusion strategy. The constructed Chinese Climate Zone Time Series LCZ (CClimate-TLCZ) dataset derived from Landsat-8 data with a 30 m spatial resolution, covering 18 representative cities in China, were used to evaluate the proposed framework. The experimental results demonstrate that the proposed framework achieved optimal outcomes across 18 cities, with an average overall accuracy exceeding 94 %, which is more than 20 % higher than that obtained by the standard WUDAPT method. Furthermore, the analysis of LCZ mapping-driven land surface temperature (LST) and surface UHI (SUHI) applications shows that cities within the same climate zone have similar LST distribution patterns, while significant heterogeneity exist between different zones. The annual consistency of LST patterns within each climate zone supports the validity of the LCZ classification scheme and accurate LCZ mapping for urban thermal environment studies. From 2016 to 2022, SUHI intensity initially increases and then decreases, indicating improvements in the urban thermal environment. These findings underscore the critical role of precise LCZ mapping in urban climate resilience and sustainable urban planning.

代表城市结构和土地利用模式的地方气候区(LCZ)方案对于城市热岛(UHI)研究至关重要。考虑到空间和时间异质性的细粒度 LCZ 制图可以更精确地描述地表热特性,从而在气候变化研究中实现对时空趋势的全面分析和理解。然而,基于数据驱动的深度学习方法在应对现实世界场景中复杂的城市景观时存在局限性,包括不同低碳区的光谱相似性和城市低碳区类别的地理空间异质性。在本研究中,我们考虑了先前的地表空间信息,包括一组光谱指数和城市形态参数(UMPs),构建了一个地理知识库,用于增强 LCZ 特征。然后,我们将可解释的地理知识库以端到端的方式集成到可学习的深度学习框架中,通过多层次融合策略融合多源异构数据,实现精确的低纬度区测绘。为了评估所提出的框架,我们使用了由Landsat-8数据构建的中国气候区时间序列LCZ(CClimate-TLCZ)数据集,该数据集的空间分辨率为30米,覆盖了中国18个具有代表性的城市。实验结果表明,所提出的框架在 18 个城市中取得了最佳结果,平均总体精度超过 94%,比标准 WUDAPT 方法高出 20%以上。此外,对 LCZ 绘图驱动的地表温度(LST)和地表 UHI(SUHI)应用的分析表明,同一气候带内的城市具有相似的 LST 分布模式,而不同气候带之间存在显著的异质性。各气候区内 LST 分布模式的年度一致性证明了 LCZ 分类方案的有效性,并为城市热环境研究提供了精确的 LCZ 地图。从 2016 年到 2022 年,SUHI 强度先上升后下降,表明城市热环境有所改善。这些发现强调了精确绘制 LCZ 图在城市气候适应性和可持续城市规划中的关键作用。
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引用次数: 0
Seasonally inundated area extraction based on long time-series surface water dynamics for improved flood mapping 基于长时间序列地表水动态的季节性淹没区提取,用于改进洪水测绘
IF 10.6 1区 地球科学 Q1 GEOGRAPHY, PHYSICAL Pub Date : 2024-08-20 DOI: 10.1016/j.isprsjprs.2024.08.002

Accurate extraction of Seasonally Inundated Area (SIA) is pivotal for precise delineation of Flood Inundation Area (FIA). Current methods predominantly rely on Water Inundation Frequency (WIF) to extract SIA, which, due to the lack of analysis of dynamic surface water changes, often yields less accurate and robust results. This significantly hampers the rapid and precise mapping of FIA. In the study, based on the Harmonic Models constructed from Long Time-series Surface Water (LTSW) dynamics, an SIA extraction approach (SHM) was introduced to enhance their accuracy and robustness, thereby improving flood mapping. The experiments were conducted in Poyang Lake, a region characterized by active hydrological phenomena. Sentinel-1/2 remote sensing data were utilized to extract LTSW. Harmonic analysis was applied to the LTSW dataset, using the amplitude terms in the harmonic model to characterise the frequency of variation between land and water for the surface units, thus extracting the SIAs. The results reveal that the harmonic model parameters are capable of portraying SIA. In comparison to the commonly used WIF thresholding method for SIA extraction, the SHM approach demonstrates superior accuracy and robustness. Leveraging the SIA extracted through SHM, a higher level of accuracy in FIA extraction is achieved. Overall, the SHM offers notable advantages, including high accuracy, automation, and robustness. It offers reliable reference water extents for flood mapping, especially in areas with active and complex hydrological dynamics. SHM can play a crucial role in emergency response to flood disasters, providing essential technical support for natural disaster management and related departments.

准确提取季节性淹没区(SIA)是精确划分洪水淹没区(FIA)的关键。目前的方法主要依靠水淹没频率(WIF)来提取季节性淹没区,由于缺乏对地表水动态变化的分析,其结果往往不够准确和可靠。这极大地阻碍了快速、精确地绘制 FIA 图。在本研究中,基于长时间序列地表水(LTSW)动态变化构建的谐波模型,引入了一种 SIA 提取方法(SHM),以提高其准确性和鲁棒性,从而改善洪水测绘。实验在水文现象活跃的鄱阳湖进行。利用哨兵-1/2 遥感数据提取 LTSW。对 LTSW 数据集进行谐波分析,利用谐波模型中的振幅项来描述地表单元的水陆变化频率,从而提取 SIA。结果表明,谐波模型参数能够描绘 SIA。与常用的提取 SIA 的 WIF 阈值法相比,SHM 方法具有更高的准确性和鲁棒性。利用 SHM 方法提取的 SIA,可以实现更高水平的 FIA 提取精度。总体而言,SHM 具有显著的优势,包括高精度、自动化和稳健性。它为洪水测绘提供了可靠的参考水域范围,尤其是在水文动态活跃而复杂的地区。SHM 可以在洪水灾害的应急响应中发挥重要作用,为自然灾害管理和相关部门提供必要的技术支持。
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引用次数: 0
Sub-national scale mapping of individual olive trees integrating Earth observation and deep learning 结合地球观测和深度学习绘制国家以下尺度的橄榄树个体地图
IF 10.6 1区 地球科学 Q1 GEOGRAPHY, PHYSICAL Pub Date : 2024-08-19 DOI: 10.1016/j.isprsjprs.2024.08.003

The olive tree holds great cultural, environmental, and economic significance in the Mediterranean region. In particular, Morocco has been making dedicated investments over $10 billion since 2008 to fuel the transition from cereal to olive production. Understanding the spatial extent of this large-scale land conversion is critical for a variety of socioeconomic purposes. In response to this demand, we conducted a study to map individual olive trees in northern Morocco using satellite imagery and deep learning techniques at a sub-national scale. This study utilized cloud-free, very-high-resolution DigitalGlobe imagery collected between 2018 and 2022 to identify each individual olive tree in six northern Morocco provinces. We compared various deep learning models, including both transformer-based and CNN-based models, to generate patch-level spatial constraints and pixel-level tree identification. We found that transformer-based models outperformed CNN-based models in both tasks. Additionally, spatially constraining the pixel-level results improved olive tree mapping accuracy to varying degrees, depending on the initial performance of the model. The evaluation of the olive map generated from this study shows high accuracy in both surveyed and unsampled regions. This research represents the first-of-its-kind individual olive tree mapping at the sub-national scale that can help monitor the large-scale land conversions such as about 110,000 ha of olive plantings in the six Moroccan provinces studies here. Meanwhile it demonstrates a cost-effective and efficient prototype approach that can be adapted to identify similar tree crop expansion occurring in other parts of the world.

橄榄树在地中海地区具有重要的文化、环境和经济意义。特别是,自 2008 年以来,摩洛哥一直在进行超过 100 亿美元的专项投资,以推动从谷物生产向橄榄生产的转型。了解这种大规模土地转换的空间范围对于各种社会经济目的至关重要。为了满足这一需求,我们开展了一项研究,利用卫星图像和深度学习技术在次国家尺度上绘制摩洛哥北部的橄榄树个体地图。这项研究利用 2018 年至 2022 年期间收集的无云、极高分辨率 DigitalGlobe 图像,识别了摩洛哥北部六个省份的每一棵橄榄树。我们比较了各种深度学习模型,包括基于变换器的模型和基于 CNN 的模型,以生成斑块级空间约束和像素级树木识别。我们发现,基于变换器的模型在这两项任务中的表现都优于基于 CNN 的模型。此外,对像素级结果进行空间约束在不同程度上提高了橄榄树映射的准确性,这取决于模型的初始性能。对本研究生成的橄榄树地图进行的评估显示,在调查过的区域和未取样的区域都有很高的精确度。这项研究是首次在次国家尺度上绘制个体橄榄树地图,有助于监测大规模的土地转换,例如本研究中摩洛哥六个省约 110,000 公顷的橄榄树种植。同时,它还展示了一种成本效益高、效率高的原型方法,可用于确定世界其他地区类似的林木作物扩张情况。
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引用次数: 0
Coarse-to-fine semantic segmentation of satellite images 卫星图像从粗到细的语义分割
IF 10.6 1区 地球科学 Q1 GEOGRAPHY, PHYSICAL Pub Date : 2024-08-16 DOI: 10.1016/j.isprsjprs.2024.07.028

Training deep neural networks for semantic segmentation of aerial images relies heavily on obtaining a large number of precise pixel-level annotations, which can cause significant annotation expenses. Given the fact that acquiring fine-class annotations is considerably more challenging than obtaining coarse-class annotations, we present a novel semi-supervised learning framework, which utilizes high spatial resolution images annotated with coarse-class labels alongside a very small set of fine-grained annotated images as the training set, thereby achieving classification results that are refined in both spatial resolution and categorical granularity. Specifically, this framework adopts Mix Transformer (MiT) as the backbone architecture to accommodate both local feature extraction and long-range dependency modeling capabilities and utilizes multi-prototype learning to model each class as multiple sub-prototypes, preserving the intrinsic variance characteristics within classes. We propose a dedicated co-training approach tailored for extracting fine-grained pseudo-labels from coarse-grained samples. In this approach, a local-softmax pseudo-labeling strategy is developed to ensure a harmonious balance between the efficiency and accuracy of the pseudo-labeling, and four losses are formulated for both single-level class and cross-category granularity supervised learning. We evaluate the proposed framework on the Gaofen Image Dataset (GID) and Five-Billion-Pixels (FBP) dataset, confirming its feasibility and superior results. In particular, based on coarse-class annotations, the performance achieved using only 5% of fine-class labels, in terms of the four metrics, namely mIoU, mean UA, mean F1-score, and OA, reached 91%, 96%, 89%, and 93% of the fully-supervised baseline performance respectively. The code is available at https://github.com/chenhaocs/C2F.

训练用于航空图像语义分割的深度神经网络在很大程度上依赖于获取大量精确的像素级注释,这可能会导致大量的注释费用。鉴于获取细粒度注释比获取粗粒度注释更具挑战性,我们提出了一种新颖的半监督学习框架,利用注有粗粒度标签的高空间分辨率图像和极少量的细粒度注释图像作为训练集,从而获得在空间分辨率和分类粒度上都更加精细的分类结果。具体来说,该框架采用 Mix Transformer(MiT)作为骨干架构,兼顾了局部特征提取和长距离依赖建模功能,并利用多原型学习将每个类建模为多个子原型,从而保留了类内的内在差异特征。我们提出了一种专门用于从粗粒度样本中提取细粒度伪标签的联合训练方法。在这种方法中,我们开发了一种局部软最大伪标签策略,以确保伪标签的效率和准确性之间的和谐平衡,并为单级类别和跨类别粒度监督学习制定了四种损失。我们在高分图像数据集(GID)和五十亿像素数据集(FBP)上对所提出的框架进行了评估,证实了其可行性和优越性。特别是在粗类注释的基础上,仅使用 5%的细类标签,在 mIoU、平均 UA、平均 F1 分数和 OA 四个指标上取得的性能分别达到了完全监督基线性能的 91%、96%、89% 和 93%。代码见 https://github.com/chenhaocs/C2F。
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引用次数: 0
From satellite-based phenological metrics to crop planting dates: Deriving field-level planting dates for corn and soybean in the U.S. Midwest 从卫星物候指标到作物播种日期:推导美国中西部玉米和大豆的田间播种日期
IF 10.6 1区 地球科学 Q1 GEOGRAPHY, PHYSICAL Pub Date : 2024-08-16 DOI: 10.1016/j.isprsjprs.2024.07.031

Information on planting dates is crucial for modeling crop development, analyzing crop yield, and evaluating the effectiveness of policy-driven planting windows. Despite their high importance, field-level planting date datasets are scarce. Satellite remote sensing provides accurate and cost-effective solutions for detecting crop phenology from moderate to high resolutions, but remote sensing-based crop planting date detection is rare. Here, we aimed to generate field-level crop planting date maps by taking advantage of satellite remote sensing-derived phenological metrics and proposed a two-step framework to predict crop planting dates from these metrics using required growing degree dates (RGDD) as a bridge. Specifically, we modeled RGDD from the planting date to the spring inflection date (derived from phenological metrics) and then predicted the crop planting dates based on phenological metrics, RGDD, and environmental variables. The ∼3-day and 30-m Harmonized Landsat and Sentinel-2 (HLS) products were used to derive crop phenological metrics for corn and soybean fields in the U.S. Midwest from 2016 to 2021, and the ground truth of field-level planting dates from USDA Risk Management Agency (RMA) reports were used for the development and validation of our proposed two-step framework. The results indicated that our framework could accurately predict field-level planting dates from HLS-derived phenological metrics, capturing 77 % field-level variations for corn (mean absolute error, MAE=4.6 days) and 71 % for soybean (MAE=5.4 days). We also evaluated the predicted planting dates with USDA National Agricultural Statistics Service (NASS) state-level crop progress reports, achieving strong consistency with median planting dates for corn (R2=0.90, MAE=2.7 days) and soybeans (R2=0.87, MAE=2.5 days). The model’s performance degraded slightly when predicting planting dates for fields with irrigation (MAE=5.4 days for corn, MAE=6.1 days for soybean) and cover cropping (MAE=5.4 days for corn, MAE=5.6 days for soybean). The USDA RMA Common Crop Insurance Policy (CCIP) provides county- or sub-county-level crop planting windows, which drive producers’ decisions on when to plant. Within the CCIP-driven planting windows, higher prediction accuracies were achieved (MAE for corn: 4.5 days, soybean: 5.2 days). Our proposed two-step framework (phenological metrics-RGDD-planting dates) also outperformed the traditional one-step model (phenological metrics-planting dates). The proposed framework can be beneficial for deriving planting dates from current and future phenological products and contribute to studies related to planting dates such as the analysis of yield gaps, management practices, and government policies.

有关播种日期的信息对于建立作物生长模型、分析作物产量和评估政策导向的播种窗口的有效性至关重要。尽管非常重要,但田间水平的播种日期数据集却很少。卫星遥感为中高分辨率的作物物候探测提供了精确而经济的解决方案,但基于遥感的作物播种日期探测却很少见。在此,我们旨在利用卫星遥感得出的物候指标生成田间级作物播种日期图,并提出了一个两步框架,以必要生长度日期(RGDD)为桥梁,根据这些指标预测作物播种日期。具体来说,我们建立了从播种日期到春季拐点日期的 RGDD 模型(来自物候指标),然后根据物候指标、RGDD 和环境变量预测作物播种日期。我们利用∼3 天和 30 米的大地遥感卫星和哨兵-2(HLS)协调产品推导出美国中西部地区 2016 年至 2021 年玉米和大豆田的作物物候指标,并利用美国农业部风险管理署(RMA)报告中田间种植日期的地面实况来开发和验证我们提出的两步框架。结果表明,我们的框架可以根据 HLS 派生的物候指标准确预测田间种植日期,玉米的田间变化率为 77%(平均绝对误差 MAE=4.6 天),大豆的田间变化率为 71%(平均绝对误差 MAE=5.4 天)。我们还根据美国农业部国家农业统计服务局 (NASS) 州级作物进度报告对预测播种日期进行了评估,结果与玉米(R2=0.90,MAE=2.7 天)和大豆(R2=0.87,MAE=2.5 天)的中位数播种日期非常一致。在预测灌溉田(玉米 MAE=5.4 天,大豆 MAE=6.1 天)和覆盖种植(玉米 MAE=5.4 天,大豆 MAE=5.6 天)的播种期时,模型的性能略有下降。美国农业部 RMA 共同作物保险政策 (CCIP) 提供了县级或县级以下的作物播种窗口,促使生产者决定何时播种。在 CCIP 驱动的种植窗口内,预测准确率更高(玉米的 MAE 为 4.5 天,大豆为 5.2 天)。我们提出的两步框架(物候指标-RGDD-播种日期)也优于传统的一步模型(物候指标-播种日期)。建议的框架有助于从当前和未来的物候产品中推导出种植日期,并有助于与种植日期有关的研究,如产量差距分析、管理实践和政府政策。
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引用次数: 0
Unveiling spatiotemporal tree cover patterns in China: The first 30 m annual tree cover mapping from 1985 to 2023 揭示中国树木覆盖的时空格局:首次绘制1985-2023年30米年树木覆盖图
IF 10.6 1区 地球科学 Q1 GEOGRAPHY, PHYSICAL Pub Date : 2024-08-13 DOI: 10.1016/j.isprsjprs.2024.08.001

China leads in the greening of the world, with a nearly doubled increase in its forest area since the 1980 s revealed by the National Forest Inventory (NFI). However, a significant challenge persists in the absence of consistent and reliable remote sensing data that align with the NFI, hindering a comprehensive understanding of the spatiotemporal patterns of terrestrial ecosystem changes driven by afforestation and reforestation efforts over recent decades in China. Moreover, conventional binary thematic maps and land use and land cover (LULC) maps encounter difficulties in providing a thorough assessment of canopy cover at the subpixel level and trees extending beyond officially designated forest boundaries. This limitation creates substantial gaps in our comprehension of their invaluable contributions to ecosystem services. To confront these challenges, this study presents a systematic framework integrating time-series Landsat satellite imagery and random forest-based ensemble learning techniques. This framework aims to generate China’s inaugural annual tree cover dataset (CATCD) spanning from 1985 to 2023 at a 30 m spatial resolution. Evaluation against multisource reference data shown high correlations ranging from 0.70 to 0.96 and reasonable RMSE values ranging from 5.6 % to 25.2 %, highlighting the reliability and precision of our approach across different years and data collection methodologies. Our analysis reveals that China’s forested area has doubled, expanding from 1.04 million km2 in 1985 to 2.10 million km2 in 2023. Notably, 33 % of this growth can be attributed to a shift from non-forest to forest land categories, primarily observed in the three-north and southwest regions. However, the majority, contributing 67 %, results primarily from crown closure in central and southern China. This realization underscores the limitations of conventional binary thematic maps and LULC maps in accurately quantifying forest gain in China. Furthermore, China’s tree population structure has undergone a transformative shift from 83 % forest trees and 17 % non-forest trees in 1985 to 92 % forest trees and 8 % non-forest trees in 2023, signifying a transition from afforestation to established forests. Our study not only enhances the understanding of tree cover variations in China but also provides valuable data for ecological investigations, land management strategies, and assessments related to climate change.

国家森林资源清查(NFI)显示,自 20 世纪 80 年代以来,中国的森林面积增加了近一倍,在世界绿化进程中居于领先地位。然而,由于缺乏与《国家森林资源清查》相一致的可靠遥感数据,全面了解中国近几十年来植树造林和重新造林所导致的陆地生态系统变化的时空模式成为一大挑战。此外,传统的二元专题地图和土地利用与土地覆盖(LULC)地图在提供亚像素级树冠覆盖和官方指定森林边界以外树木的全面评估方面也存在困难。这种局限性使我们在理解它们对生态系统服务的宝贵贡献方面存在巨大差距。为了应对这些挑战,本研究提出了一个整合时间序列大地卫星图像和基于随机森林的集合学习技术的系统框架。该框架旨在生成中国首个年度树木覆盖数据集(CATCD),时间跨度为 1985 年至 2023 年,空间分辨率为 30 米。根据多源参考数据进行的评估显示,相关性从 0.70 到 0.96 不等,均方根误差值从 5.6 % 到 25.2 % 不等,显示了我们的方法在不同年份和数据收集方法中的可靠性和精确性。我们的分析显示,中国的森林面积翻了一番,从 1985 年的 104 万平方公里扩大到 2023 年的 210 万平方公里。值得注意的是,33% 的增长可归因于非林地向林地类别的转变,这主要体现在三北和西南地区。不过,67%的增长主要来自华中和华南地区的树冠郁闭。这凸显了传统二元专题地图和 LULC 地图在准确量化中国森林增量方面的局限性。此外,中国的树木种群结构发生了转变,从 1985 年的 83% 林地和 17% 非林地树木转变为 2023 年的 92% 林地和 8% 非林地树木,这标志着从植树造林向人工林的过渡。我们的研究不仅加深了对中国林木覆盖率变化的理解,还为生态调查、土地管理策略和气候变化相关评估提供了宝贵数据。
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引用次数: 0
Fraction-dependent variations in cooling efficiency of urban trees across global cities 全球城市中城市树木冷却效率的分数变化
IF 10.6 1区 地球科学 Q1 GEOGRAPHY, PHYSICAL Pub Date : 2024-08-09 DOI: 10.1016/j.isprsjprs.2024.07.026

Investigating the relationship between cooling efficiency (CE) and tree cover percentage (TCP) is critical for planning of green space within cities. However, the spatiotemporal complexities of the intra-city CE-TCP relationship worldwide with distinct climates, as well as the differing impacts of consistently increasing tree cover within urban regions on cooling potential, remain unclear. Here we used satellite-derived MODIS observations to investigate the CE-TCP relationship across 440 global cities during summertime from 2018 to 2020. We further investigated the impacts of enhancing tree cover by a consistent amount in different urban locales on the reduction of population heat exposure among specific age groups. Our results demonstrate a nonlinear CE-TCP relationship globally – CE exhibits an initial sharp decline followed by a gradual reduction as TCP rises, and this nonlinearity is more pronounced in tropical and arid climates than in other climate zones. We observe that 91.4% of cities experience a greater reduction in population heat exposure when introducing the same amount of TCP in areas with fewer trees than in those with denser canopies; and heat exposure mitigation is more prominent for laborers than for vulnerable groups. These insights are critical for developing strategies to minimize urban heat-related health risks.

研究降温效率(CE)与树木覆盖率(TCP)之间的关系对于城市绿地规划至关重要。然而,全球范围内不同气候条件下城市内CE-TCP关系的时空复杂性,以及城市区域内树木覆盖率持续增加对降温潜力的不同影响仍不清楚。在此,我们利用源自卫星的 MODIS 观测数据,研究了 2018 年至 2020 年夏季全球 440 个城市的 CE-TCP 关系。我们进一步研究了在不同城市地区提高一定数量的树木覆盖率对减少特定年龄组人群热暴露的影响。我们的研究结果表明,在全球范围内,CE 与 TCP 之间存在非线性关系--CE 最初急剧下降,随后随着 TCP 的上升而逐渐降低,这种非线性关系在热带和干旱气候中比其他气候区更为明显。我们观察到,如果在树木较少的地区引入相同数量的 TCP,91.4% 的城市会比在树冠较密的地区减少更多的人口热暴露;与弱势群体相比,劳动者的热暴露缓解更为显著。这些见解对于制定最大限度降低城市热相关健康风险的战略至关重要。
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引用次数: 0
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ISPRS Journal of Photogrammetry and Remote Sensing
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