[Gdal-dev] I/O Performance issues with ENVI data format

[Ozy Sjahputera]

I have a C++ program that conducts UTM reprojection and resampling of 
large images before creating the pansharpened multispectral images.  
Initially, I was using GTiff format for the pansharpened image.  For 
16Kx16K panchromatic image (and its corresponding multispectral), it 
took me about 50 minutes to finish the process.  Then I tried using ENVI 
format as a solution to the 4 GB limit of GTiff.  The whole process 
(using the same input images) now take more than 3 hours to complete.  
Both programs were built using the release mode with the same 
optimization options in VC.Net.

Both trials were run on the same machine with XP-SP2.  Any idea why the 
disk I/O with the ENVI format is much slower compared to the disk I/O 
with the GTiff format?

Thanks

Ozy