Iowa Environmental Mesonet

Iowa State University Department of Agronomy

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IEM RadMap API

Please note: This mapping service is provided without warranty. Please do not use this on a high traffic website. If necessary, this application may be disabled to keep the IEM web farm from melting! This API is intended to support local scripts to generate timelapse movies.

The "radmap" application dynamically generates a PNG image based on a set of HTTP provided parameters. This page documents these parameters. Please note that the API presented here may change in the future.

Basic HTML example:

<img src="http://mesonet.agron.iastate.edu/GIS/radmap.php?layers[]=nexrad§or=conus&ts=200806071000" />

HTTP GET Parameters

&layers[]=...&layers[]=...&...

Layer(s) to draw in the map. Here is a list of available layers:
  • uscountines - CONUS Counties
  • nexrad - CONUS Nexrad Base Reflectivity Composite
  • watch_by_county - Convective Watch-by-County
  • watches - Polygon SPC Watch boundaries
  • cbw - County/Zone based Watch/Warning/Advisories
  • sbw - Storm based Watch/Warning/Advisories
  • county_warnings - County based Warnings
  • lsrs - Local Storm Reports
  • roads - Iowa Winter Road Conditions
  • legend - Include Legend on the Map

§or=...

Predefined areal extent to use for the map. Current sectors are:
  • iem - Iowa
  • lot - Chicago
  • ict - Wichita, Kansas
  • sd - South Dakota
  • hun - Northern Alabama
  • conus - CONUS
  • texas - Texas

&width=640&height=480

Width and height of the map in pixels.

&vtec=...

VTEC identification string of a specific product. The result is a map centered on this product with a timestamp set to product issuance. An example VTEC string is: "2008.DMX.TO.W.0048".

&pid=...

This is for the specific example of offices who issue geometries with their SPS statements. An example string is: "200903082123-KGRR-WWUS83-SPSGRR"

&bbox=xmin,ymin,xmax,ymax

Bounding box of the map (typically a latitude and longitude box). An example would be "-95.4,40.1,-89.4,44.5".

&ts=YYYYMMDDHHII

Timestamp in GMT for which the map is valid for. For example, 6:45 GMT on 5 Jun 2005 would be "200506050645".

&title=....

A customized title to place on the map.

Example Python client script

Here is an example python script that will call this service and locally generate a folder of images that can then be converted into a movie. 

#!/usr/bin/env python

import datetime, os

# Generate series of images between 0z and 12z on the 3rd of August
now = datetime.datetime(2008,8,3,0,0)
ets = datetime.datetime(2008,8,3,12,0)
interval = datetime.timedelta(minutes=5)

baseuri = "http://mesonet.agron.iastate.edu/GIS/radmap.php?"
baseuri += "width=800&height=600&bbox=-95,42.5,-89,45.5"
baseuri += "&layers[]=uscounties&layers[]=nexrad&layers[]=sbw"
baseuri += "&layers[]=watch_by_county"

# Change into a frames folder
os.chdir("frames")
stepi = 0
while (now < ets):
  url = "%s&ts=%s" % (baseuri, now.strftime("%Y%m%d%H%M"))
  cmd = "wget -q -O %05i.png '%s'" % (stepi, url )
  os.system(cmd)
  stepi += 1
  now += interval

os.system("ffmpeg -y -i %05d.png -b 2000k out.mp4")

Change Log

  • 10 Mar 2009: Initial release