Linear scale (source code)

= Linear scale
{title2=$u=ax+c,\quad a>0$}

A <linear scale> places a value $x$ at a position $u=ax+c$, where $a>0$ and $c$ are <constants>. Equal differences in $x$ occupy equal distances because $u_2-u_1=a(x_2-x_1)$. This contrasts with a <logarithmic scale>, which assigns equal distances to equal <ratios>.