How can I add color AND a node label to a scatter plot?

Question

I'd like to produce a scatter plot from a data file. The data file could look like this:

 x       y       color   myvalue
 0.5     0.2     1       test
 0.2     0.1     2       uniform

I'd like to add the string data in column myvalue to the nodes, but still have the option to colour the marks. I tried two things recommended in the manual:

\begin{tikzpicture}
  \begin{axis}[% scatter/use mapped color={draw=black,fill=mapped color},
              enlargelimits=0.2]
    \addplot[scatter, mark=*,only marks, 
            scatter src=explicit symbolic,
            nodes near coords,]
      table [x=x, y=y, meta=myvalue] {tab.tbl};

   \end{axis}
\end{tikzpicture}

This allows me to put the labels to the marker in the plot.

But I don't know how to add colours. My second attempt was to use the colour for the point meta data (manual page 88), but then I couldn't add text (it would only accept numbers in the code below):

\begin{tikzpicture}
  \begin{axis}[enlargelimits=0.2]
     \addplot[scatter, mark=*,only marks,
              scatter src=explicit symbolic,
           % we use ’point meta’ as color data...
           point meta=\thisrow{color},
           % ... therefore, we can’t use it as argument for nodes near coords ..
           nodes near coords*={\myvalue},
           % ... which requires to define a visualization dependency:
           visualization depends on={\thisrow{myvalue} \as \myvalue},
           ]
           table [x=x, y=y, meta=myvalue] {tab.tbl};
  \end{axis}
\end{tikzpicture}

How can I have both?

Answer 1

oh, I found the solution in a related question.

How to use a string column to label datapoints in pgfplots.

The key is to use value in front of the macro definition.

The working code is:

\begin{tikzpicture}
  \begin{axis}[% scatter/use mapped color={draw=black,fill=mapped color},
              enlargelimits=0.2]
     \addplot[scatter, mark=*,only marks,
           % we use ’point meta’ as color data...
           point meta=\thisrow{color},
           % ... therefore, we can’t use it as argument for nodes near coords
           nodes near coords*={\myvalue},
           % ... which requires to define a visualization dependency:
           visualization depends on={value \thisrow{myvalue} \as \myvalue},
           ]
           table [x=x, y=y]
           {tab.tbl};
  \end{axis}

\end{tikzpicture}