GeoExpress accesses image data in 'blocks' of pixels.
Blocks in MG3 and MG4 encoding are different from blocks in MG2 encoding. The block size parameter in MG3 controls how large the bitplane-encoded regions are. Lowering this parameter may lower the memory usage of the encoder but may also decrease the lossless compression ratio. Raising this parameter may increase memory usage, but may improve the lossless compression ratio. This parameter has little effect on overall encode time. Typical values range from 32 to 64.
Acceptable values: 5 - 64
Default: 64