read gzipped files in situ (e.g. raster.tif.gz)

[matt.wilkie@…]

I've run into a fair amount of raster imagery, OnEarth for example, which is available gzipped instead of using an internal compression. It would be very convenient if gdal could read gzipped files in situ. Having to decompress the files to a scratch space first means having to keep a lot extra room around to manouver. In other applications which do read .gz files such as VTP it also seems to be a lot faster to read/write a .gz than an uncompressed file. Perhaps because of less disk use (?).

[warmerdam]

A special file handler something like the one used for in-memory files could
be implemented to achieve this.  However, it is not partiuclarly high on my
personal priority list.  Due to challenges seeking in compressed data
streams it might be necessary to decompress the whole file into RAM which 
would not scale well to large datasets.