标题： 高分辨率卫星影像中的覆盖偏差 显示英文标题

标题： Coverage Biases in High-Resolution Satellite Imagery

摘要： 卫星图像越来越多地被用于补充传统数据收集方法，如调查和人口普查，在各个学科中。然而，我们提出疑问：地球上所有地方是否都平等地受益于这一新的信息财富？ 在本研究中，我们调查了提供地面采样距离小于10米的光学卫星图像的主要卫星星座的覆盖偏差，评估了未来按需任务的机会以及全球历史图像的可用性。 具体而言，从前瞻性角度来看，我们根据卫星的轨道路径估计在30天的时间窗口内不同地点被重新访问的频率，从而调查由物理因素引起的潜在覆盖偏差。 我们发现，离赤道更远的地方通常被研究中的星座更频繁地重访。 回顾过去，我们展示了基于从主要卫星图像提供商收集的元数据，历史卫星图像的可用性受到地面社会经济因素的影响：欠发达、人口较少的地方拥有较少的卫星图像。 此外，在三个关于最近冲突地区的案例研究中，即加沙、苏丹和乌克兰，我们展示了地缘政治事件也在卫星图像的可用性中扮演重要角色，这暗示了潜在的商业模式决策。 这些见解揭示了卫星图像带来的数字红利在全球分布并不均匀。 显示英文摘要

摘要： Satellite imagery is increasingly used to complement traditional data collection approaches such as surveys and censuses across scientific disciplines. However, we ask: Do all places on earth benefit equally from this new wealth of information? In this study, we investigate coverage bias of major satellite constellations that provide optical satellite imagery with a ground sampling distance below 10 meters, evaluating both the future on-demand tasking opportunities as well as the availability of historic images across the globe. Specifically, forward-looking, we estimate how often different places are revisited during a window of 30 days based on the satellites' orbital paths, thus investigating potential coverage biases caused by physical factors. We find that locations farther away from the equator are generally revisited more frequently by the constellations under study. Backward-looking, we show that historic satellite image availability -- based on metadata collected from major satellite imagery providers -- is influenced by socio-economic factors on the ground: less developed, less populated places have less satellite images available. Furthermore, in three small case studies on recent conflict regions in this world, namely Gaza, Sudan and Ukraine, we show that also geopolitical events play an important role in satellite image availability, hinting at underlying business model decisions. These insights lay bare that the digital dividend yielded by satellite imagery is not equally distributed across our planet.