Xtics logscale

If the logscale attribute is set for a tic series along a log-scaled axis, the tic interval is interpreted as a multiplicative factor rather than a constant. For example:
    # generate a series of tics at y=20 y=200 y=2000 y=20000
    set log y
    set ytics 20, 10, 50000 logscale
Note that no tic is placed at y=50000 because it is not in the series 2*10^x. If the logscale property is disabled, the tic increment will be treated as an additive constant even for a log-scaled axis. For example:
    # generate a series of tics at y=20 y=40 y=60 ... y=200
    set log y
    set yrange [20:200]
    set ytics 20 nologscale
The logscale attribute is set automatically by the set log command, so normally you do not need this keyword unless you want to force a constant tic interval as in the second example above.