Disaster response / Near real-time mapping

Latency: From Orbit to Application COM-001 Latency in satellite systems is the total time between a sensor observing something on Earth and that observation becoming usable information. It is not one delay — it is a chain of them. Propagation through space, queuing at ground stations, decryption, format conversion, atmospheric correction, reprojection, tiling, indexing, and delivery. Some links are governed by physics and cannot be shortened. Others are engineering choices. Understanding where latency lives determines what questions you can answer with the data. A flood map delivered in 15 minutes can direct evacuations. The same map delivered in 48 hours is a historical record. SAR Fundamentals SEN-005 Synthetic Aperture Radar (SAR) is a radar imaging system carried on aircraft or satellites that creates high-resolution images of the Earth's surface by emitting microwave pulses and measuring what bounces back. Unlike optical sensors that rely on sunlight, SAR generates its own illumination — so it works at night. Unlike optical sensors that are blocked by clouds, SAR's microwave frequencies pass through clouds, rain, and smoke. SAR does not see color or reflected light. It sees surface roughness, moisture content, and geometric structure. This makes it essential for flood mapping, deforestation monitoring, ground deformation measurement, and any application where persistent, all-weather observation is required. Analysis-Ready Data DAT-004 Analysis-Ready Data (ARD) is satellite imagery that has been processed to a standard where it can be used directly for analysis without additional preprocessing. This means the image has been geometrically corrected (pixels are in the right geographic locations), radiometrically calibrated (pixel values represent meaningful physical quantities like surface reflectance rather than arbitrary digital numbers), atmospherically corrected (the atmosphere's distortion has been removed), and often cloud-masked (unusable pixels are flagged). ARD is the difference between receiving raw ingredients and receiving a prepared, measured, recipe-ready mise en place. Data Provenance SEC-001 Data provenance is the complete, verifiable record of where a piece of data came from, every transformation it underwent, and who or what performed those transformations. In satellite imagery and remote sensing, provenance is not a nice-to-have audit trail — it is the difference between evidence and hearsay.