METHOD: HACHURE

Steep ground crowds the mark.

Here, white persists
where almost nothing is level.

Above it,
the darkest mass
will not resolve
to elevation.

DO NOT INTERPOLATE ACROSS VOIDS.

The eye had crossed
before interdiction.

VERTICAL CONTROL

datum:     

zero is stipulated,
then propagated upslope
through every value that follows.

The lower control
has passed beneath the neatline;

orography remains
legible without it.

RELIEF

high−low,

provided both terms
survive reduction.

One is entered.
The other had already
fallen out of sheet.

INDEX CONTOUR

Every so often, a heavier line
returns the climb to legibility.

Beyond this interval,
continuity is only
presumed, and the sheet closes
on whatever     turns out to be.