Mr. Radar is a minimalist Python application for rendering radar data from the National Weather Service of the United States. Radar data is rendered using the standard NWS color scale and saved in png format. An HTML page is generated which layers the radar images with user-specified map layers and displays the radar images in an animated loop.
Fill out the config.ini file with your desired radar layer(s), map
layers, and latitude/longitude extents. Then call mr_radar.py
periodically (or pass the --repeat flag with a refresh interval in
seconds). The png files with radar data and html file of the
animation will be placed in named folders corresponding to the radar
layer names in the configuration file.
The make_map.py, level3_to_png.py, and generate_html.py files
are also callable as standalone utilities. make_map.py downloads
and stitches together map tiles to generate a png map image.
level3_to_png.py renders a "level 3" radar data file to a png image
over the specified extents. generate_html.py creates an HTML radar
animation with the png images that are present in a specified directory.
Raw radar files are downloaded from the National Weather Service
FTP server.
It can be helpful to explore the
directory browser
to identify the path for your desired radar site and product.
The most recent radar file in each directory is named sn.last.
Currently, Mr. Radar only supports base reflectivity products
(e.g. product codes p19r0 and 180z0). Composite products use a
rectangular pixel grid (instead of the polar pixel grid which we
assume), and non-reflectivity products require different colormaps.
It should not be too difficult to add support for these products in a
future release.
More information about radar file formats and data processing is available on my website.
Map data and radar data are rendered using a web Mercator projection. As such, map data can be downoaded from nearly any online map service using the standard "slippy" tile format, including any of the tile servers listed by OpenStreetMap.
A base map layer is rendered beneath the radar data, and an overlay map layer is rendered above the radar data. If the overlay map layer is used, it must be mostly transparent in order to avoid obscuring the radar data. The toner-lines tiles from Stamen Design work exceptionally well. (The problem with only rendering map data beneath radar data is that you can't see the map at all when there is a big storm.)
Map tiles are automatically fetched and stitched together into a
single png image on the first call to mr_radar.py. The latitude and
longitude extents of the png image are stored in the png metadata. The
cached map image is not automatically refreshed when the URL or
extents are changed; remove base_map.png and overlay_map.png from
the output directory whenever it is necessary to regenerate the map.
- Improve the HTML page with a UI to control animation speed.
- Performance profiling and improvements.
- Support for additional radar products (composite reflectivity, radial velocity, etc).
- Better packaging of Python files.