Note that many transformation functions are available using the scales package : log10_trans(), sqrt_trans(), etc. Use help(trans_new) for a full list.

Note that, since ggplot2 v2.0.0, date and datetime scales now have date_breaks, date_minor_breaks and date_labels arguments so that you never need to use the long scales::date_breaks() or scales::date_format().

This R tutorial describes how to modify x and y axis limits (minimum and maximum values) using ggplot2 package. Axis transformations (log scale, sqrt, …) and date axis are also covered in this article.

It is also possible to use the functions scale_x_continuous() and scale_y_continuous() to change x and y axis limits, respectively.