I have a project to expand tzdata. Summarizing shortly, the rough idea is to - add boundary descriptions to each area with a different timezone history so that with given coordinates it can automatically be determined to which timezone history 'table' a given location belongs. I am aware that many non-trivial issues of geo-information processing arise with such a goal. - add more details for the complicated timezone history of some countries, e.g. Canada, where other sources have identified more than 250 regions with different timezone history, whereas current tzdata has only 15 regions. I am aware that this is a large project which will require resources measured in man-years. I may be in a position to contribute/sponsor such resources. I would like to communicate with the current maintainers of tzdata about these ideas, and about the best approach for such an expansion. My motivation background is the field of serious astrology, where reliable timezone history information is an essential requirement. tzdata is doing an excellent job to provide reliable information for current timzones, but it lacks sadly (and understandably, given the complexity of the problem) in historical detail. Alois Treindl