# Aligning relatively positioned nodes in TikZ

\documentclass{standalone}
\usepackage{standalone}
\usepackage{amsmath}
\usepackage{amssymb}

\usepackage{tikz}
\usetikzlibrary{shapes, positioning}

\begin{document}
\begin{tikzpicture}
\tikzstyle{every node}=[font=\scriptsize]
\tikzstyle{apr}=[rectangle,
align=center,
text width = 3cm,
node distance = 1cm,
rectangle split, rectangle split parts=2,
draw, fill=white]

\node(1) [apr]
{
\textbf{Lore Ipsum}\\ \textbf{Dolor}
\nodepart{second} {\begin{aligned} x = &\: 10 \\ y = &\: 20 \\ \dot{x} = &\: 0 \end{aligned}}
};
\node(4) [apr, right = of 1]
{
\textbf{Lore Ipsum}\\ \textbf{Stupid Descenders}
\nodepart{second} {\begin{aligned} x = &\: 10 \\ \dot{x} = &\: 0 \end{aligned}}
};

\end{tikzpicture}
\end{document}


How can I make the tops of the nodes align instead of their centers?

Here is the image:

-
Welcome to TeX.sx! \node (4) [apr, right = of 1.base east, anchor=base west] could be one way, or north instead of base. –  Qrrbrbirlbel Dec 12 '12 at 18:22
And not related to TikZ, but the correct use of amsmath align environments is & = instead of spacing tricks like = & \:. See Relation spacing error using =& in aligned equations –  Qrrbrbirlbel Dec 12 '12 at 18:25

Use appropiate anchor in the relatively positioned node, and specify the appropiate corner in the right = of ... option:
[...]

Note that the order here is important. right = of ... sets the anchor to west so you need to override it by setting anchor=north west afterwards. Putting anchor=north west before right=of ... has no effect. –  Loop Space Dec 12 '12 at 19:42