Continuity and Change in the Computer era 207
include pressure, spatial acuity, and position. Others that provide sensory informa-
tion are heat and cold, and pain, but these have not yet been used in haptic maps. It
is unlikely that pain would be used as a mapping variable, but certainly, if hardware
is developed to support it, temperature could be a valuable addition, especially for
weather and climate maps (Table 11.1).
In making maps for the visually impaired, the mapmaker must pay particular
attention to audience needs and abilities. Not all visually impaired users have the
same degree of blindness, and there are differences based on whether the user is blind
from birth or became blind through accident or disease at a later age (adventitiously).
Adventitiously blind users have memory of sight and this can be an important factor.
Additionally, those who are blind through diabetic retinopathy, an eye complication
of diabetes, often have a reduced sense of touch in their fingers, making braille read-
ing difficult or impossible. Haptics and sound are an option in this case.
