2

The issue that I am having with the image of my longtable is that the caption is not centered and I have vertical lines that appear above my table. I have looked up other posts about my errors but non resolve the issue. 

\begin{center}
\begin{longtable}{|c|c|c|}
\centering
\caption{Average Scalar Flux Groups 1 and 2 Test  C} \\
\hline
\rowcolor[gray]{0.85}\textbf{Average Scalar Flux Group 1} 
&\textbf{Average Scalar Flux Group 2} & \textbf{Distance} \\  
\hline
2.185692E-17    &   4.194769E-18        &       0.00 \\ \hline
-1.202652E-04   &   1.202652E-04        &       0.10\\ \hline
-2.405521E-04   &   2.405521E-04        &       0.20\\ \hline
-1.839872E-04   &   1.894445E-04        &       0.30\\ \hline
-1.295853E-04   &   1.403995E-04        &       0.40\\ \hline
-7.678566E-05   &   9.288239E-05        &       0.50\\ \hline
1.078685E-04    &   -1.078685E-04       &       22.30\\ \hline
0.000000E+00    &   0.000000E+00        &       22.40\\ \hline
\label{tlabel}
\end{longtable}
\end{Center}

This is what it looks like. The rest of the table looks fine. It is also cutting off a word in my header above the horizontal line at the top of the page on the left hand side. enter image description here

Megan
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1 Answers1

3

You shouldn't enclose the longtable in a center environment, because the table will be centered by default. Also, \label should go besides the \caption.

\documentclass{article}
\usepackage[margin=2cm]{geometry}
\usepackage{colortbl,longtable}
\usepackage{lipsum} % just for the example
\begin{document}

\lipsum[2]

\begin{longtable}{|c|c|c|}
\caption{Average Scalar Flux Groups 1 and 2 Test  C}
\label{tlabel} \\
\hline
\rowcolor[gray]{0.85}\textbf{Average Scalar Flux Group 1} 
&\textbf{Average Scalar Flux Group 2} & \textbf{Distance} \\  
\hline
2.185692E-17    &   4.194769E-18        &       0.00 \\ \hline
-1.202652E-04   &   1.202652E-04        &       0.10\\ \hline
-2.405521E-04   &   2.405521E-04        &       0.20\\ \hline
-1.839872E-04   &   1.894445E-04        &       0.30\\ \hline
-1.295853E-04   &   1.403995E-04        &       0.40\\ \hline
-7.678566E-05   &   9.288239E-05        &       0.50\\ \hline
1.078685E-04    &   -1.078685E-04       &       22.30\\ \hline
0.000000E+00    &   0.000000E+00        &       22.40\\ \hline
\end{longtable}

\lipsum[3]
\end{document}

enter image description here

Note that in the standard page setup for the article class the table is too wide, so it will stick in the right margin.

An even better result will be obtained with the help of the siunitx package that's able to format numbers in various ways. Note, in particular, that the hyphens in the preceding example should be minus signs.

\documentclass{article}
\usepackage[margin=2cm]{geometry}
\usepackage{colortbl,longtable,siunitx}
\usepackage{lipsum} % just for the example

\sisetup{
  output-exponent-marker=\ensuremath{\mathrm{E}},
  exponent-product={},
}

\begin{document}

\lipsum[2]

\begin{longtable}{
  |S[table-format=-1.6e-2]|
   S[table-format=-1.6e-2]|
   S[table-format=2.2]|
}
\caption{Average Scalar Flux Groups 1 and 2 Test  C}
\label{tlabel} \\
\hline
\rowcolor[gray]{0.85}\textbf{Average Scalar Flux Group 1}
&\textbf{Average Scalar Flux Group 2} & \textbf{Distance} \\  
\hline
2.185692E-17    &   4.194769E-18        &       0.00 \\ \hline
-1.202652E-04   &   1.202652E-04        &       0.10\\ \hline
-2.405521E-04   &   2.405521E-04        &       0.20\\ \hline
-1.839872E-04   &   1.894445E-04        &       0.30\\ \hline
-1.295853E-04   &   1.403995E-04        &       0.40\\ \hline
-7.678566E-05   &   9.288239E-05        &       0.50\\ \hline
1.078685E-04    &   -1.078685E-04       &       22.30\\ \hline
0.000000E+00    &   0.000000E+00        &       22.40\\ \hline
\end{longtable}

\lipsum[3]
\end{document}

enter image description here

You should also consider this possible enhancement, that avoids many problems both in readability and in horizontal spacing.

\documentclass{article}
\usepackage[margin=2cm]{geometry}
\usepackage{longtable,siunitx,booktabs}
\usepackage{lipsum} % just for the example

\sisetup{output-exponent-marker=\ensuremath{\mathrm{E}},exponent-product={}}

\begin{document}

\lipsum[2]

\begin{longtable}{
  S[table-format=-1.6e-2]
  S[table-format=-1.6e-2]
  S[table-format=2.2]
}
\caption{Average Scalar Flux Groups 1 and 2 Test  C}
\label{tlabel} \\
\toprule
\multicolumn{2}{c}{\textbf{Average Scalar Flux}} & {\textbf{Distance}} \\
\cmidrule{1-2}
{\textbf{Group 1}} & {\textbf{Group 2}} & \\
\midrule
 2.185692E-17 &  4.194769E-18 &  0.00 \\
-1.202652E-04 &  1.202652E-04 &  0.10 \\
-2.405521E-04 &  2.405521E-04 &  0.20 \\
-1.839872E-04 &  1.894445E-04 &  0.30 \\
-1.295853E-04 &  1.403995E-04 &  0.40 \\
-7.678566E-05 &  9.288239E-05 &  0.50 \\
 1.078685E-04 & -1.078685E-04 & 22.30 \\
 0.000000E+00 &  0.000000E+00 & 22.40 \\
\bottomrule
\end{longtable}

\lipsum[3]
\end{document}

enter image description here

egreg
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