To add labels to a grid, Hans wrote a macro hlintext (Min, Max, Step, Lenght
, Format). I do not know what to put in "Format".
Best regards,
Fabrice

\definecolor[mycolor][c=.4,m=0,y=0,k=0]
\starttext
\start
\switchtobodyfont[small]
\startMPcode
     input tex;
     numeric xmin, xmax, ymin, ymax;
     xmin := 0; xmax := 22; ymax :=460 ;ymin:=0; u := 0.5cm; v:= 0.025cm;
     drawoptions(withpen pencircle scaled 0.5pt withcolor
\MPcolor{mycolor});
     draw hlingrid(ymin,ymax,20,11.5cm,11cm);
     draw vlingrid(xmin,xmax,2,11cm,11.5cm);
     drawoptions(withpen pencircle scaled 1pt) ;
     drawarrow (0,0)--(22,0) scaled u ;
     drawarrow (0,0)--(0,460) scaled v ;
     for i=0 step 2 until 20 :
        label.bot(TEX("$"&decimal(i)&"$"),(i,0)*u);
     endfor;
     for i=0 step 20 until 440:
        label.lft(TEX("$"&decimal(i)&"$"),(0,i)*v);
      endfor;
     label.bot( "$x$",(10.8cm,-0.1cm)) ;
     label.rt( "$y$",(0.1cm,11.3cm)) ;

\stopMPcode
\stop
\stoptext