when creating web graphics
it makes the best sense to fit them
to the average browser window
and similarly when visualising (eg)
the Tree of Life
it makes sense to scale the visualisation
down to the appropriate human scale
eg the whole worldmap
shrunk to the width of a notebook page
or the whole history of life
(3 billion years)
shrunk to the height
of a stack of books
(or a breadbox)
but more often
we'll need to zoom in
with both horizontal zoom
(for space)
and independently
vertical zoom (for time)
so we zoom in on our chosen time-span
until it fits the height of a breadbox
and on our chosen space-map
to fit the width of a notebook page
eg Leopold Bloom's wanderings
by foot, carriage, and tram
over the 16 hours of Ulysses
span two miles square
with most of the day spent standing
more-or-less still
(ie, a vertical line
on the Tree of Life)
and Bloom's walking speed
at this scale
by contrast
is quick enough to appear
almost horizontal
so here
and in general
human worldlines are normally
all right angles
lacking any obvious diagonals
(unless the topic
of the zoomed map
is the trip itself)
.