Mdtryhht

This question is related to Strange behavior in TikZ draw command but is not the same.

While working with coordinates and nodes in TikZ, I was expecting that:

 coordinate (x) at (4,0) node[right] $x$;
 coordinate (y) at (0,3) node[above] $y$; 

and

 node[right] at (x) $x$;
 node[above] at (y) $y$;

would yield the same result. But they don't. I get the following output:

With coordinate (x) at (4,0) node[right] $x$;, I meant, the system will create a node at (4,0) and will place the text $x$ to its right.

Based on the output, I see the text $x$ is placed at (0,0), with the above command.

Why does this happen.

MWE:

documentclassarticle
usepackagetikz
usetikzlibraryintersections
begindocument
begintikzpicture
 coordinate (x) at (4,0) node[right] $x$;
 coordinate (y) at (0,3) node[above] $y$;

 node[right] at (x) $x$;
 node[above] at (y) $y$;

 draw[<->,thick] (0,3) |- (4,0);
endtikzpicture
enddocument 

try the following:

documentclassarticle
usepackagetikz
%usetikzlibraryintersections not used in this mwe

begindocument
begintikzpicture
 coordinate[label=right:$x$] (x) at (4,0);
 coordinate[label=above:$y$] (y) at (0,3);

 draw[<->,thick] (y) |- (x);
endtikzpicture
enddocument

In section 17.2.1 of the TikZ manual, the commands for such works are shown:

• 
  

  path ... node ... (1.1)

  
  
  

  or node ... (1.2)

  
  


• 
  

  path ... coordinate ... (2.1)

  
  
  

  or coordinate ... (2.2)

  
  

coordinate ... node ... are not present!

That is why coordinate (x) at (4,0) node[right] $x$; and node[right] at (x) $x$; don't give the same result. In fact, coordinate (x) at (4,0) node[right] $x$; is understood as

coordinate (x) at (4,0); 
path node[right] $x$; % (0,0) in case no coordinates are specified

That is why we get

with this code

documentclass[tikz]standalone
begindocument
begintikzpicture
coordinate (x) at (2,0) node[draw,right] world;
fill (x) circle (1pt)
 (0,0) circle (1pt);
endtikzpicture
enddocument

and we get

with this code

documentclass[tikz]standalone
begindocument
begintikzpicture
node[draw] (x) at (2,0) Hello node[draw,right] world;
fill (0,0) circle (1pt);
endtikzpicture
enddocument

So how to solve it? We can't combine (2.2) or (1.2) with ... node ..., but we can do it with (1.1) or (2.1):

path (4,0) coordinate (x) node[right] $x$;

Remember that draw, fill, filldraw... are all daughters of path, so they are all valid. But node and coordinate are not.

I found this using the draw powerful trick :)

It doesn't give you the expected result because the syntax is not appropriate. (At which level do you expect an explanation? Does it help that in coordinate (x) at (4,0) node[right] $x$; at (4,0) got "absorbed" by coordinate (x) so that TikZ adds the default coordinate (0,0) to interpret node[right] $x$?) You can condense all statements to one line.

documentclass[tikz,border=3.14mm]standalone
begindocument
begintikzpicture
 draw[<->,thick] (0,3) coordinate (y) node[above] $y$ |- (4,0) coordinate (x) node[right] $x$;
endtikzpicture
enddocument