Convert velo to legend scale

Q&A
1

Hi all,

Could you please help me to plot a vector on legend using “gmt legend” command when the real vector I plotted using “gmt velo -Se0.5c/0.95/0 …”

Regards,

Susilo

2

Unfortunately, those specialty symbols produced by the seis and geodesy supplements cannot easily be placed in the legend. We are working on this issue but no released solution yet. You will have to fake it by maybe plotting a regular white ellipse with legend and then by trial-and-error guess the coordinates you need to plot that single error-ellipse in the right spot on the legend.

3

Thanks Paul for your reply

4

It’s indeed a pain to do it … Don’t know if it can help, but here’s my way “to fake it”

The plot :

gmt grdvector tmp_u10.nc tmp_v10.nc -Gblack -Wthickest,black -Si${length_wanted}c -Q${head_wanted}c+e+a45+jc+n15
  • -Si defines a scale for the vector length
    *-Q defines a width of the head (+n up/downscale what’s above/below the value 15 here)

Then the legend :

gmt legend -DjTR+w$(echo "scale=3; 60*${length_wanted};"|bc)c+o-5p/2p -F+r4p+pthinnest,gray+gwhite <<- END
S - v${head_wanted}c+e+a45 $(echo "scale=3; 10*${length_wanted};"|bc)c black 2p - 10m.s@+-1@+
        END
  • First line defines the legend rectangle
  • Second line is the actual legend (Symbol - vector …)

Hopefully it might be useful…

5

Thank you very much for your reply

Susilo

6

Hello,
I would like to know if it is still not possible to plot in the legend the symbol of a vector (plotted with fig.velo) with its respective scale (no fake).

7

Not that I’m aware of. It has been pushed into not priority feature on github.
Though, I wonder if there could be a trick with the new windbar module?