# How to indicate radius (or size) of circle when it's defined as \path node[shape=circle]at(x,y){}?

I need to change the size of the circle but using radius doesn't work here.

\documentclass{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\path node(ID1)[draw,shape=rectangle]{ID1};
\path node[draw=red,shape=circle]at(ID1.north){};
\end{tikzpicture}
\end{document}

• It's neither nor. If you want a circle of radius exactly 2pt, try \documentclass{standalone} \usepackage{tikz} \begin{document} \begin{tikzpicture} \path node(ID1)[draw,shape=rectangle]{ID1}; \path node[draw=red,shape=circle,minimum size=4pt,inner sep=0pt,outer sep=0pt]at(ID1.north){}; \draw[blue] (ID1.north east) circle[radius=2pt]; \end{tikzpicture} \end{document} – user121799 Feb 15 at 23:24

## 1 Answer

There are several pgf keys that matter, which you can control by setting minimum size and inner sep appropriately. inner sep is, to a good approximationif the radius is not "too small". If you want to control the radius very precisely, useinner sep=0ptandminimum size=.

\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}
\path node(ID1)[draw,shape=rectangle]{ID1};
\path node[draw=red,shape=circle,minimum size=4pt,inner sep=0pt,outer sep=0pt]at(ID1.north){};
\draw[blue] (ID1.north east) circle[radius=2pt];
\end{tikzpicture}
\end{document}
`