Automated Data Plotter

This application dynamically generates many types of graphs. These graphs are derived from processing of various data sources done by the IEM. Please feel free to use these generated graphics in whatever way you wish. Reset App. The IEM Explorer application offers a simplified frontend to some of these autoplots.


First, select a chart type::


Second, select specific chart options::

Aggregate Population or Area
At Valid Timestamp:
How to consider if an event is active [see footnote]
Image Pixel Size @100 DPI
Image Resolution (DPI) (50 to 500)
Select Output Format:

Plot Description:

This autoplot attempts to estimate the number of people or area in the US under a given NWS Watch/Warning/Advisory (WaWA). Double-accounting is somewhat a problem here in the case of overlapping polygons. For each WaWA type, if there are polygons associated with the event, the population of the polygon intersection with the 30 arc-second grid is used.

While the graphic only displays the top 10, the data download provides everything available to be computed.

Footnote on "Active" WaWA: A more complex than it should be nuance to explain here is the concept of what is "active" at a given timestamp. Let us consider a real world example. On Monday afternoon, the NWS issues a Winter Storm Warning for an upcoming storm that goes "into effect" at noon on Tuesday. You request this plot for a timestamp of 6 PM on that Monday. Is the Winter Storm Warning included in this metric at that time?

  • Yes, if you select the option to include any WaWA that have been created, but may have an VTEC start time in the future yet.
  • No, if you select the option to only include WaWA that have an issuance time before the given timestamp.

The default setting here is the first option, to include any events that have been created, but not necessarily having an issuance time prior to the given timestamp. This is why we can't have nice things!

Autoplot 247 is closely related to this app and provides a map of WaWa + stats.


Based on a sampling of recent timings for this application, plot generation time has averaged 3 seconds. Hold on for the plot is generating now!


View Data (as csv)   Download as Excel  
If you notice plotting issues with the image above, please do let us know by providing the URL address currently shown by your web browser.

IEM Daily Features using this plot

The IEM Daily Features found on this website often utilize plots found on this application. Here is a listing of features referencing this plot type.