# How can I plot a smooth line of fit through the following points and is there an easier way to plot (x,y) labels for each point?

\documentclass{standalone}
\usepackage{pdfpages}
\usepackage{tikz}
\usepackage{pgfplots, pgfplotstable}
\pgfplotsset{compat=1.12}
\usepgfplotslibrary{fillbetween}
\usepackage{amsmath}

\begin{document}
\centering
\begin{tikzpicture}
\pgfplotsset{scale only axis}
\begin{axis}[xmin=0, xmax=1000, ymin=-3000, ymax=8000, xlabel=$\phi M_u\;(kNm)$, ylabel=$\phi N_u\;(kN)$]
\addplot [color=blue, ,text=black, only marks, mark = *, mark options={fill=blue,}, visualization depends on=\thisrow{alignment} \as \alignment, nodes near coords, point meta=explicit symbolic, every node near coord/.style={anchor=\alignment}] table [meta index=2] {
x       y           label           alignment
0   7190    (0,\;7190)      -160
631     4748    (631,\;4748)    -160
895     2174    (895,\;2174)    0
442     0       (442,\;0)       160
0   -1971   (0,\;-1971)     160
};
\end{axis}
\end{tikzpicture}
\end{document}


So you mean something like the following?

\documentclass[border=5pt]{standalone}
\usepackage{pgfplots}
\pgfplotsset{
compat=1.3,
/pgf/declare function={
% polynomial coefficients calculated in Excel
a0 = 539.4248043;
a1 = 0.213478271;
a2 = -4.00837E-05;
% declare polynomial function
f(\x) = a0 + a1*\x + a2*(\x)^2;
},
}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
xmin=0,
xmax=1000,
ymin=-3000,
ymax=8000,
xlabel=$\phi M_u\;(kNm)$,
ylabel=$\phi N_u\;(kN)$,
scale only axis,
]
text=black,
only marks,
visualization depends on=\thisrow{alignment} \as \alignment,
% here you can define what should be shown in the nodes near coords'
nodes near coords={%
\footnotesize%
$(\pgfmathprintnumber{\pgfkeysvalueof{/data point/x}}, \pgfmathprintnumber{\pgfkeysvalueof{/data point/y}})$%
},
node near coords style={
anchor=\alignment,
/pgf/number format/1000 sep={},
},
] table {
x    y      alignment
0    7190   -160
631  4748   -160
895  2174   90
442  0      -30
0    -1971  160
};

`