[GRASS5] [bug #4037] (grass) d.vect.thematic: fails to generate a legend for >20 custom_breaks

[Daniel Calvelo]

[Maciek found a misspecification in d.vect.thematic: the
legend-drawing code is designed for a small number of categories;
going from 20 up, it feeds negative coordinates into d.graph, which
chokes and spits]

What is the right solution?

a) allow >20 items in the legend, shrinking it to fit all of them
b) make the legend with only 20 items (say the 10 lower, a mark and
the 10 upper) with a warning
c) signal >20 items as an error or warning and do not output the legend
d) other suggestion

I like b). c) is of course the easiest. a) is a little involved (since
this is sh) and it would allow for legends of arbitrary number of
items, which makes unreadably absurd legends possible.

Daniel.

-- Daniel Calvelo Aros