You are here: Appendix B: File Sizes and Memory Usage > Calculating memory usage

Calculating memory usage

The amount of memory that GeoExpress uses to perform operations depends on the following factors:

Of these factors, you can control the strip height and the block size that GeoExpress uses.

Memory usage is constant over the length of the encode operation.

MG3 and MG4 memory usage

The following formula describes the approximate amount of memory used by GeoExpress to compress a single image to the MrSID Generation 4 (MG4) or MrSID Generation 3 (MG3) format:

Memory = ((8 + 4 × BlockSize + MIN(StripHeight, BlockSize)) × 4 + StripHeight) × NumBands × Width

The following list describes the variables used by the formula:

MG2 memory usage

The following formula describes the approximate amount of memory used by GeoExpress to compress a single image to the MrSID Generation 2 (MG2) format:

Memory = ((8 + 4 × BlockSize + 64) × NumBands × Width × 4) + (0.005 × ExpectedOutputFileSize)