OpenStreetMapProvider
RadMap can visualize data from the OpenStreetMaps REST services. You can enable tile caching to a local folder setting a new LocalFileCacheProvider to the OpenStreetMapProvider.CacheProvider property.
Figure 1: OpenStreetMapProvider
Using OpenStreetMapProvider
Using Encrypted HTTP Version
A TLS 1.2 SecurityProtocol will be required when modifying the RadMap URL to use https:\ while using OpenStreetMapProvider. This protocol automatically comes with .NET Framework 4.7. For older .NET Frameworks, or because of some other Windows settings, it may be necessary to explicitly choose TLS 1.2 for your application by setting the System.Net.ServicePointManager.SecurityProtocol property to SecurityProtocolType.Tls12. Otherwise the tiles won't be donwload while using https://. This is further described in the Transport Layer Security (TLS) best practices with the .NET Framework MSDN article.