If you want to be absolutely sure that the figure will be placed at the top of the next page (as opposed to, possibly, the top of the page where the \begin{figure}
directive is detected), you should use the afterpage
package and its \afterpage
command:
\documentclass{article}
\usepackage{afterpage,natbib,lipsum}
\usepackage[demo]{graphicx}
\begin{document}
\lipsum[1-3]
\afterpage{%
\begin{figure}[t!] % use "t!" to force the float to start the float at top of page
\centering
\includegraphics[width=0.9\textwidth]{C:/Thesis/Latex/thesis_1(1)/Figures/studyArea.jpg}
\rule{35em}{0.3pt}
\caption{The Grand St.~Bernard wireless sensor network deployment
(a) the coordinates of nodes according to the Swiss coordinate system
(b) the distribution of the nodes in the study site \citep{r33}}
\label{fig:studyarea} % better not to have a space in the "label"
\end{figure}
} % end of "afterpage" group
\lipsum[4-6]
\end{document}
Addendum: Assuming that the line you wish to draw between the graph and caption should span the entire width of the text block, I would recommend using the command \rule{\textwidth}{0.3pt}
instead of \rule{35em}{0.3pt}
.
[t]
if it should be on the next page. I suppose that you do not need\FloatBarrier
. And by the way: there is no optionf
for the placement of a float,