Custom AirNow Maps - Troubleshooting and Fixing Errors

Unfortunately, the mapping system is not designed to give you error messages or correct you when you enter incorrect values in your web address. Nor does it give you consistent behavior that indicates what error is made.

Even trivial changes will completely confuse the system, so if you’re having problems, please look through what you created carefully and make sure that it lines up with the documentation precisely. For example, the value “Xmin” confuses the mapping system. It must be “xmin”—all lower case—for the map to recognize it.

Another common error is putting the same variable in twice (or more). This is a particularly easy mistake to make when you create complex custom maps, like we did in the section Putting It All Together. Even if you do same variable twice in exactly the same way, it will confuse the system.

Finally, the map does not prevent you from making errors of logic that display nonsensical data. For example, the system will allow you to display the Contours for PM2.5, but the Monitors for Ozone. This will result in a map where the colors are completely out of sync-- because the monitor Ozone values will not match the contour for PM2.5!

As always, if you’ve done what you can and the system is not working for you, please feel free to email the Airnow team at airnowquestions@epa.gov.