Why does The National Map Viewer link (http://viewer.nationalmap.gov/viewer) sometimes not initially open or load for international users?
International users should first set your Internet browser language to "English/United States" to be able to access The National Map Viewer. Use the following instructions dependent on the browser being used:
Chrome: Help-How to use Chrome-Language and display settings
Internet Explorer: Tools-Internet Options-General Tab-Languages (under the Appearance section at the bottom)
Then access TNM Viewer link after first clearing your browser history and using the Ctrl-F5 keys to refresh the cache with new web content. If Internet Explorer (IE) still does not work, then use a different browser, such as Chrome or Firefox, because IE may be too restrictive on ActiveX Directory security settings to allow viewer access.