IEM Provided RADAR Information for GIS

Our RadView project is an effort to get real time NWS NEXRAD information into GIS applications. We have no magic bullets for getting this information into GIS systems, but have a number of things for you to try out!

These services are provided with-out warranty and with program interfaces that may change or go away!

Quick links to specific products


NEXRAD + Mapserver Howto:

Here is a HOWTO on generating NEXRAD composites with GEMPAK and then displaying them in Mapserver. Feedback is certainly welcome.

Geo-referenced Images:

Using geo-referenced images is probably the simpliest way of getting data into your GIS. Displaying timestamps and color bars are tricky business. The following URLs contain pure RASTER data layers.
RADAR EPSG Proj Code Data Files World File
US Base Reflectivity (N0R) Composite
(generated every 5 minutes)
Decimal Degree Units
US Storm Total Precip (NTP) Composite
(generated every 5 minutes)
Decimal Degree Units
US 1 Hour Precip (N1P) Composite
(generated every 5 minutes)
Decimal Degree Units
KCCI-TV SuperDoppler
(generated every 2-3 minutes)
UTM Zone 15N

Web Map Service (WMS):

WMS is a neat way to pull in images into your GIS, if your GIS can act as a WMS client. Describing WMS is beyond the scope of this page, but we have set up a WMS on our webserver. Point your WMS aware client at

for Iowa imagery in EPSG: 26915 (NAD83 / UTM Zone 15N)
Base Reflectivity:
1 Hour Rainfall:
Storm Total Rainfall:

for United States imagery in EPSG: 4326 (unprojected lat-lon)

Note: The WMS service should be able to send back an image in the projection of your choice. This has worked during the limited testing done in house.

There are many free web WMS clients available on the Internet. Recently, ESRI has released an OGC extension supporting WMS for their free client called ArcExplorer. After downloading ArcExplorer, you will want to also download the Interoperability Extension. ESRI has also released an extension for ArcIMS!

Notes and Caveats:

  1. The storm total precipitation (NTP) product does not directly composite. Each NEXRAD site reports the value for a different timespan. Basically, once the radar detects rain, it will begin to accumulate the rainfall in the NTP product. Once it stops raining for an hour, the value is reset to zero. Since all sites reset at different times, you see the issue.