## Efficient table reading

This document shows that the default table ordering is unefficient (but there are good reasons for this ordering, see Section ). For an efficient gridding process you should:

- give XY_MAP the right to allocate as much as memory as possible, e.g. 90% of the RAM (assuming you run a single CLASS session at a time), leaving typically 10% for the regular OS operations,
- if the problem still does not fit in memory, it is worth transposing the .tab table to .bat order before invoking XY_MAP.

This can be achieved with the commands

    LAS> TRANSPOSE myfile.tab myfile.bat 21
    LAS> SIC LOGICAL VOLATILE_MEMORY 90%
    LAS> XY_MAP myfile  ! Will take myfile.bat if available

Note that the memory allocated during XY_MAP processing is freed as soon as the command terminates.