[Gdal-dev] Tiff on the CD

[Fu Chen]

Hi!
If many situations, the original tiff file can't be modified(on CD or DVD or file marked with ReadOnly property), but the user still like it be zoomed out smoothly. In CD, the read speed is much slowly than harddisk, so if I take RasterIO to build a overview of whole image on screen will take a long time. If the user wanna access the data more than once, it will be better we keep a overview cache on harddisk. Next time the user insert the CD or DVD (maybe access on a automatic CD library), the software will recognize the file(by CD volume number or something else), and associate the overview cache in the harddisk with it.
If we can't sperate overviews from details in Geotiff format. If it possible to create new feature in vrt that tell where to find the overviews and where to find the detail.

Any idea?