在非洲各地，农田正转变为住宅区，定居点不断扩张，城市边界也在变化。通常，这种增长速度超过了地图和规划系统的更新能力。值此10月31日世界城市日之际，值得探讨决策者是否拥有规划这一增长所需的信息。[...]

Across Africa, fields are turning into housing areas, settlements are expanding, and city borders are shifting. Often, this growth happens faster than our maps and planning systems can keep up with. As we mark World Cities Day on 31st October, it’s worth asking if decision-makers have the information they need to plan for this growth. […]

今年，主题聚焦于如何通过城市更新改善住房可及性，并助力建设包容且具备气候韧性的社区。全球约有28亿人面临某种形式的住房问题，近11亿人居住在贫民窟或非正规住区。非洲向城市生活的转型使这一挑战更为紧迫。联合国预测显示，非洲大陆人口可能从2020年的约13.4亿增长至2050年的约24.9亿，其中大部分增长将发生在城镇和中等规模城市。规划充足住房始于了解人们定居的地点以及城市区域的变化情况：哪些社区增长最快，绿地在哪里缩减，以及哪些住区位于洪水风险区。这些答案有助于规划者理解需求，并确定行动最为紧迫的区域。Digital Earth Africa 为用户提供卫星数据访问权限，帮助追踪城市随时间的变化。通过利用多年来的卫星图像，用户可以观察城市如何扩张，并利用这些信息为可持续城市发展做出更好的决策。绘制城市地图不仅仅是衡量城市扩张的程度。Digital Earth Africa 的工具允许用户绘制建成区地图、检查绿地和树木覆盖情况，并计算可持续发展报告所需的指标。结合水和洪水数据，这些工具有助于规划者将土地利用与人们的日常需求联系起来：明确哪些住区面临反复的洪水风险，哪些区域最需要改进，以及在何处增加绿地可以使社区更宜居。然而，卫星数据无法回答所有规划问题，但它为进一步研究、社区参与和政策决策提供了坚实的证据基础。获取这些工具只是故事的一部分，人们还需要使用它们的技能。Digital Earth Africa 的自定进度城市化课程专为没有卫星数据或编程背景的人士设计。它帮助规划者、研究人员及其他人员建立实用技能，以研究城市增长并将卫星数据作为证据使用。然而，当证据缺失或过时，决策就会变得更加困难。卫星数据可以帮助城市了解其城区如何变化，发现新挑战，并就投资和服务提供的地点提出更清晰的问题。

This year, the theme focuses on how renewing urban areas can improve access to housing and help build inclusive, climate-resilient neighbourhoods. Around the world, about 2.8 billion people face some form of housing problem, and nearly 1.1 billion live in slums or informal settlements. Africa’s move toward city living makes this challenge even more urgent. United Nations projections show that the continent’s population could grow from about 1.34 billion in 2020 to around 2.49 billion by 2050, with much of this growth happening in towns and medium-sized cities. Planning for adequate housing starts with understanding where people are settling and how the city area is changing. Which neighbourhoods are growing fastest, where is green space shrinking as well as which settlements are in areas at risk of flooding. These answers can help planners understand needs and decide where action is most urgent. Digital Earth Africa gives users access to satellite data that helps track changes in cities over time. By using satellite images from many years, users can see how cities have grown and use this information to make better decisions for sustainable city development. Mapping cities is more than just measuring how much a city has grown. Digital Earth Africa tools let users map built-up areas, check green space and tree cover, and calculate measures for sustainability reports. Combined with water and flood data, these tools help planners connect land use to people’s daily needs on which settlements face repeated flood risks, which areas need improvements the most and where could more green space make neighbourhoods more liveable. However, satellite data can not answer every planning question, but it provides a solid evidence base for further study, community input, and policy decisions. Access to these tools is only part of the story, but people also need the skills to use them. Digital Earth Africa’s self-paced urbanisation course is made for those with no background in satellite data or coding. It helps planners, researchers, and others build practical skills to study city growth and use satellite data as evidence. However, decision-making is harder when evidence is missing or old. Satellite data can help cities see how their urban areas are changing, spot new challenges, and ask clearer questions about where to invest and provide services.