I am analyzing ADFS logs, which reference the SharePoint webs visited (via the wcontext parameter) but do so via their GUID.
How do I translate a SharePoint site/web GUID into a URL?
There is no direct correlation between a GUID and a URL.
If you are looking for this information from a code-behind, you could get the SPWeb object from the GUID, and poll the .URL property from there.
I used SharePoint Manager 2010 to find the GUID of a site I found in the event log. You can download it from spm.codeplex.com