Using PGFPlotstable, we can use a naive numerical integration scheme to find the function directly within LaTeX.
Edit and compile if you like:\documentclass[border=10pt]{standalone}
\usepackage{pgfplots}
\pgfplotsset{width=7cm,compat=1.8}
\usepackage{pgfplotstable}
\pgfplotstableset{
create on use/x/.style={
create col/expr={
\pgfplotstablerow/201*2-1
}
},
create on use/y/.style={
create col/expr accum={
\pgfmathaccuma+(2/201)*(abs(\pgfmathaccuma^2)+abs(\thisrow{x}^2)-1)
}{0.6}
}
}
\pgfplotstablenew{201}\loadedtable
\begin{document}
\begin{tikzpicture}
\begin{axis}[
view = {0}{90},
domain = -1:1,
y domain = -1:1,
samples = 21,
xmax = 1,
ymax = 1
]
\addplot3 [gray, quiver={u={1}, v={x^2+y^2-1}, scale arrows=0.075,
every arrow/.append style={-latex}}] (x,y,0);
\addplot [thick, red] table [x=x, y=y] {\loadedtable};
\end{axis}
\end{tikzpicture}
\end{document}
