Starting June 2018 Google has implemented a pay-as-you-go pricing model for the Google Maps Platform APIs. Previously, most users with moderate usage could use Google Maps, which are embedded into opCharts and Open-AudIT Professional/Enterprise, for free. Google's new policy is outlined HERE: https://developers.google.com/maps/documentation/javascript/usage-and-billing
In order to enable Google Maps you will need to a Google API Key follow this link and log in with your Google account: https://cloud.google.com/maps-platform/#get-started
For more information please see the following guide which includes a video. Use API Keys | Maps JavaScript API | Google Developers
If you are having issues with Google Maps API keys or your company does not have access to create Google Maps API keys, please contact the support team.
You can now manage your Google Maps API Key using the admin system in the application, for example https://your-server-name/omk/admin/general/opcharts
Once you have your Google API key you will need to add it to opCommon.nmis to enable Maps in opCharts. You can find opCommon.nmis (NMIS8 compatible) or opCommon.json (NMIS9 compatible) in /usr/local/omk/conf/, edit the file with vim (or another suitable text editor) and search for the opcharts_map_api_key property.
Open Open-AudIT Professional/Enterprise and select Admin -> Configuration -> All from the menu. Search for maps_api_key and place your API key in the value position.