{"id":6551,"date":"2026-01-23T14:46:16","date_gmt":"2026-01-23T13:46:16","guid":{"rendered":"https:\/\/revodata.nl\/?p=6551"},"modified":"2026-01-23T15:15:37","modified_gmt":"2026-01-23T14:15:37","slug":"building-a-geospatial-time-machine","status":"publish","type":"post","link":"https:\/\/revodata.nl\/nl\/building-a-geospatial-time-machine\/","title":{"rendered":"Building a Geospatial Time Machine"},"content":{"rendered":"\t\t
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Editor’s note: This post was originally published June 12th, 2025.\u00a0<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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What is environmental change detection?\n\n\n<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Think of it as a time machine for planet Earth. No flux capacitor, no DeLorean, and no Marty McFly needed!\ud83d\ude09 Just some cool tech that lets us peek into how our world changes over time.<\/p>

Detecting and understanding environmental changes is essential for informed decision-making, sustainable development, and effective disaster risk reduction. By systematically identifying and monitoring trends such as deforestation, urban expansion, and coastal erosion at an early stage, policymakers, urban planners, environmental agencies, and other relevant stakeholders can implement timely and proactive measures to mitigate adverse impacts on ecosystems, biodiversity, and vulnerable human populations.<\/p>

Change detection provides a critical evidence base for assessing the effectiveness of existing environmental policies and conservation strategies. It also plays a key role in informing the planning and development of resilient infrastructure capable of withstanding future environmental stresses. Furthermore, by offering accurate and up-to-date information, it supports more efficient resource allocation and helps prioritize areas facing the greatest risks.<\/p>

Above all, the ability to detect and interpret environmental changes enhances society\u2019s capacity to respond to climate-related challenges such as sea-level rise, extreme weather events, and habitat degradation. In this context, change detection serves as a vital tool for promoting more responsible and adaptive management of the planet in an era marked by rapid and often unpredictable transformation. While this \u201ctime machine\u201d can\u2019t rewrite history, it empowers us to learn from the past and chart a course toward a more sustainable future.<\/p>

For today\u2019s adventure, I\u2019m using Databricks and Apache Sedona , they\u2019re basically the power tools for working with geospatial data without your computer having a meltdown. And where are we headed? San Francisco,<\/em><\/strong>specifically the SoMa (South of Market)<\/em><\/strong> area! We\u2019re gonna see how it looked in August 2022 versus February 2025. Trust me, even in just a couple years, you\u2019d be surprised how much a neighborhood can transform. It\u2019s like watching your city grow up in fast-forward.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Implementation<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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The following implementation is part of the training we offer at RevoData focused specifically on leveraging the geospatial capabilities of Databricks.<\/p>

Remote sensing and photogrammetry cover a lot of ground, you\u2019ve got active and passive sensors, different types of resolution (spatial, spectral, temporal, radiometric), geo-referencing, orthophoto generation, and electromagnetic spectrum analysis. Instead of getting bogged down in all the technical details, I\u2019m going to focus on why I chose certain methods and what other options could potentially be considered. Let\u2019s get started.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Datasets<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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First things first, we need data, but what kind? For change detection in an urban environment, we typically rely on satellite or aerial images captured in at least four spectral bands: Red<\/strong>, Green<\/strong>, Blue<\/strong>, and Near Infrared (NIR)<\/strong>. Why NIR? Well, it all comes down to physics. Different sensors detect different \u2018flavors\u2019 of energy, from visible light our eyes see to invisible infrared or microwave radiation. Each sensor type reveals unique information about Earth\u2019s surface based on the specific energy waves it can measure. What the sensor \u2018sees\u2019 depends on how objects interact with these waves:<\/p>