\documentclass[]{article}
\usepackage{gensymb} %fro the \degree symbol
\usepackage{pgfplots}
\title{GPS variations on a fixed place}
\author{v. santos}
\date{}
\begin{document}

\maketitle


\begin{tikzpicture}[]
\begin{axis}[
  width=12cm,
  height=7cm,
  xlabel=Time (min),
  ylabel=latitude variation around $40.62975\degree$,
  ymajorgrids,
  enlargelimits=false,
]
\addplot[no markers,blue] table[y=latitude, y expr=\thisrowno{0}-40.62975, x=Tempo(min), col sep=comma] {gpsvalues.csv}; 
\end{axis}
\end{tikzpicture}


\begin{tikzpicture}[]
\begin{axis}[
  width=12cm,
  height=7cm,
  xlabel=Time (min),
  ylabel=longitude variation around $-8.65813\degree$,
  ymajorgrids,
  enlargelimits=false,
]
\addplot[no markers,red] table[y=longitude, y expr=\thisrowno{1}+8.65813, x=Tempo(min), col sep=comma] {gpsvalues.csv}; 
\end{axis}
\end{tikzpicture}

It could also be interesting to have the correspondent metric variations.


\end{document}