Tag-based data, particularly different XML dialects, have become a very popular way to distribute geospatial data. Formats which are both machine and human readable are generally easy to work with though they sacrifice storage efficiency for usability. These formats can become unmanageable for very large data sets but work very well in most cases.
While most formats are some form of XML (such as KML or GML), there is a notable exception. The Well-Known Text (WKT) format is fairly common but uses external markers and square brackets ("[]") to surround data instead of tags in angled brackets around data like XML does.
Python has standard library support for XML as well as some excellent third-party libraries available. Proper XML formats all follow the same structure so you can use a generic XML library to read it. Because XML is text-based, it is often easy to write it as a string instead of using an XML library. The vast majority of applications which output...