Radar Downloader

Radar Downloader 📡

SPCBot includes a high-performance downloader for raw NEXRAD Level 2 radar data, leveraging the NOAA AWS S3 archive.

📥 Quick Start (/download)

The /download command allows users to retrieve raw radar data for post-event analysis.

• Site Selection: Supports all 160+ NEXRAD sites (e.g., KTLX, KOKX).
• Time Filtering: Retrieve data by specific datetime, time range, or the "N most recent" files.
• Z-to-Z Range: Supports shorthand for Z-time ranges (e.g., start: 2200, end: 0030).

📦 Multi-Site & Zipping

• ZIP Output: For multi-file requests, the bot automatically zips the data before uploading it to Discord, respecting file size limits.
• Concurrent Downloads: Utilizes aioboto3 for non-blocking, parallel S3 downloads, significantly reducing wait times for large datasets.

☁️ S3 Integration

• Backend: Pulls directly from the unidata-nexrad-level2 bucket on AWS S3.
• Metadata Search: The bot performs real-time S3 prefix listing to find the exact filenames and timestamps required, ensuring accuracy even across UTC day boundaries.
• Efficiency: Downloads are streamed directly to a temporary buffer and then zipped, minimizing disk I/O.

🔧 Operator Controls

• Size Limits: Operators can configure the maximum number of files per request in .env to prevent resource exhaustion.
• Permissioning: Access to the downloader can be restricted to specific roles or channels via Discord's native integration settings.

🎞️ Historical Radar Loops (/radarhistory)

Generates an animated reflectivity GIF for any location and time, without needing to know a radar site code.

• Location Input: Accepts city/state, zip code, or coordinates — geocoded via OSM Nominatim.
• Site Resolution: Finds the nearest NEXRAD site via the R-tree spatial index.
• Time Handling: Converts a local date/time and timezone to UTC automatically.
• Data Source: Fetches IEM national composite N0Q reflectivity frames (frames × interval minutes, default 6 frames at 5-minute spacing, max 30 frames).
• Size Management: Frames auto-scale down if the resulting GIF would exceed Discord's 25MB upload limit; temporary files are deleted after upload.