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+# PopulationDensityData API User Story
+
+ Items | Details |
+|---|---|
+| **Summary** | The API provides estimation of Population Density for a specific area at a future period time, considering historical anonymized information of the network connected devices in the requested area.|
+| **Actors and scope** | **Scope:** Retrieve predicted population density for a defined polygonal area and time interval; provide insights into population patterns to support strategic planning. <br><br> **Use Case 1 — Drone Route Planning:** Identify zones to avoid due to high population-related risk; determine optimal time window to fly between two points (A–B) minimizing population exposure. <br><br> **Use Case 2 — Urban Planning:** Data-driven optimization of public services/resource allocation; support simulation and impact assessment for urban mobility and infrastructure planning.|
+| **Pre-conditions** | The client must provide: <br> - **Requested Area (Required):** Polygonal area defined by coordinates forming a closed loop. <br> - **Start Time (Required):** Future controlled time of departure. <br> - **End Time (Required):** Future controlled time of arrival. <br> - **Precision (Optional):** Geohash precision level. <br> - **Sink (Optional):** Destination system/endpoint for delivery. <br> - **Sink Credentials (Optional):** AuthN/AuthZ details to access the sink.|
+| **Activities / Steps** | 1) The client submits a request including the inputs above. <br> 2) The API responds **synchronously** (response body) or **asynchronously** (delivered to sink), including: <br> - **a) Cell Coordinates:** Geohash string representing the cell. <br> - **b) Population Density Metrics:** per cell in **1-hour intervals** with **min / avg / max** population. <br> - **c) Data Type (k-anonymity):** `Low_Density` (below threshold, cannot disclose) or `Density_Estimation` (values available and disclosed).|
+| **Post-conditions** | The requester can assess population-related information for drone flight operations or urban planning by using forecasted population density derived from network-connected devices within the requested area.|
+| **Exceptions** | - **Invalid input:** missing required fields or incorrect format (e.g., malformed polygon, missing Start/End Time, invalid precision). <br> - **Unsupported values:** parameters outside supported limits (e.g., time interval out of supported range, unsupported precision). <br> - **Unavailable data:** requested area/time/params not available or cannot be provided due to data protection constraints (e.g., k-anonymity).|