Using regular pgfplots you could do the following: Draw the line with the points you choose and label them with nodes. Then draw the additional distance markers using \draw
in the axis coordinate system (The concrete positions of all elements may have to be adjusted).
\documentclass{article}
\usepackage{tikz}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
\tiny
\begin{axis}[
width = 6cm,
height = 4cm,
ymajorgrids = true,
ymin=-1,
ymax=7,
xmin=-6,
xmax=6,
xtick distance=1,
ytick distance=1,
axis y line*=center,
axis x line*=center,
enlarge x limits=.12
]
\addplot+[sharp plot] coordinates {(6,3) (1,4) (-4,5) } node[below=1mm, pos=0] {A(6,3)}
node[pos=0.45,below=1mm] {P(x,y)}
node[pos=1,below=1mm] {B(-4,5)};
\draw[|-|] (axis cs:1.2,5) -- node [above, rotate=-10] {m=13} (axis cs:6.3,3.9);
\draw[|-|] (axis cs:-3.8,6) -- node [above, rotate=-10, pos=.3] {n=2} (axis cs:1.2,5);
\end{axis}
\end{tikzpicture}
\end{document}
Output:
