I welcomed the availability of high definition terrain data on my iPad which I can download for regions I really need it. Concerning this, I have two questions:

1) These data take up significantly more space than the lower resolution one. Since I can select for which regions to download it, I can taylor the compromise between storage space required and increased usability to my liking. However, it would be great if I could somehow also "release" those regions of high definition terrain data when I don't need it anymore. E.g., it might be good to have HD data for a particular flight into mountainous regions. After completion of the flight, however, I might never again visit this area and, hence, don't benefit from its being HD.

2) Is there a similar option to download HD terrain elevations for the PC version of SD?

Thanks, -- Chris.