How to make (1,1) mean (1cm,1cm) in TikZ? (Setting the units of coordinates)

Question

I have a picture in TikZ and I'd like to change the basic units of the coordinates I specify. I know I could just scale the picture, but I don't want to do that. For any given coordinate, I can write (1cm,1cm) etc for each coordinate, but I'd rather specify the "units" I want to use separately... Or for example make (1,1) mean (5ex,10ex)...

Is there a way to do this?

Answer 1

By default yes but you can compare the next results

\begin{tikzpicture}
  \draw(0,0)--(1,1);
\end{tikzpicture} 

\begin{tikzpicture}[x=2cm,y=-1cm] 
  \draw(0,0)--(1,1);    
\end{tikzpicture}  

\begin{tikzpicture}[x=5,y=5] 
  \draw(0,0)--(1,1);
\end{tikzpicture} 

\begin{tikzpicture}[x=28.45274,y=28.45274] 
  \draw(0,0)--(1,1);
\end{tikzpicture}

In the last code, we can see that without unit x and yare defined with pt

To complete the answer :

\begin{tikzpicture}
  \draw (0,0)--(600,0);
\end{tikzpicture}

Latex Error: ... Dimension too large. The unit is the cm.

\begin{tikzpicture}[x=0.01 cm]
  \draw (0,0)--(600 cm,0);
\end{tikzpicture}

again Latex Error: ... Dimension too large because 600 cm is a length and TeX uses only lengths < 575 cm.

\begin{tikzpicture}[x=0.01 cm]
  \draw (0,0)--(600,0);
\end{tikzpicture}  

This is correct ! 600 < $2^{31}-1$ . 600 is a integer and not a length and now 600 gives 6 cm