# NEXRAD Level II Archive Tool

This tool uses Spatialite (https://www.gaia-gis.it/fossil/libspatialite/index)
in conjunction with the NCEI Storm Events Database (https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/)
to archive only NEXRAD Level II data for which storms were recorded
by the National Weather Service.  Using the start and end times and
coordinates of a given storm report, this tool is able to query and
filter objects in the NEXRAD Level II Amazon bucket
(https://registry.opendata.aws/noaa-nexrad/), allowing one to only
archive volume scans for which storms were noted, from the appropriate
radar sites.

## Building

Simply run `make` to produce a Docker image pre-populated with the
NEXRAD radar site database.

## Running

Invoke `sh run.sh` to run this archival tool, passing two arguments:

* The path to a storm events database CSV export file, whose name
  as obtained from the NCEI begins with `StormEvents_details_`.  Only
  these files contain the start and end coordinates of a storm which
  are used to select data from the correct radar sites.
  
* A path to a destination directory where archived data shall be
  downloaded.  Note that files downloaded under this directory will
  be organized in the `YYYY/MM/DD/SITE/` hierarchy.
  
Other optional arguments will be passed through to the
`bin/nexrad-archive` executable within the Docker image:

* `--dry-run`

  This will avoid actually performing any archiving; instead, the
  tool indicate what actions it would take.
  
* `--quiet`

  Suppresses standard output.