Pitfalls [and Possibilities] in the Use of Maps
to Visualize Earth Data
and Understand Earth Processes
Kim Kastens
Lamont-Doherty Earth Observatory of Columbia University
Presented at workshop on Use of Visualization in
Geosciences
Carleton College, February 27, 2004
Pitfalls: Preview
• Many students are weak in projective spatial skills: bad
news for map projections
• Students’ prior map skills training may have lacked any
connection with the real world
• When maps and profiles are combined to explore a data
volume, likelihood of nonpenetrative errors
• Clearly articulating and modelling an approach to mapbased data exploration that works for professionals may
be insufficient for novices
• Understanding is not the same as believing and acting
upon.
Pitfall #1
Projective spatial skill includes the ability to anticipate the shape of a
projection (or shadow) cast by an object held up to a light.
(from Downs & Liben, 1991)
Good answers show
understanding of variation as
a function of the angle of
presentation of shape
relative to the light and
screen.
Good answers show
understanding of
variation as a function
of thickness of the
shape.
Mistaken answers
include:
• upside down
“shadows”
• incomplete
“shadows”
• concave “shadows”
of convex objects
• asymmetrical
“shadows” of
symmetrical objects
• inconsistent
treatment of thickness
of object
(from Downs & Liben, 1991)
This projective spatial skill
is important in teaching
about maps because map
projections are often
illustrated by having
students envision a light
inside the globe that
projects shapes from the
surface of the globe onto a
sheet of paper held
tangent to the Earth’s
surface.
(http://www.cfr.washington.edu/research.urbaneco/GIS_Tutorial/UEGIS-tutorial-notes.htm)
Data from Downs &
Liben (1991)
Degrees of rotation of
object from vertical
Mean number of correct answers
selected (out of 6)
30°
60°
90° (flat)
Male
5.4
5.2
5.1
Female
4.9
4.9
3.3
Male
1.1
1.3
4.9
Female
0.7
0.9
2.8
Thin
Forms
Thick
Forms
Many college students do
very poorly on Downs &
Liben’s shadow projection
test.
How well do you suppose
these students will
understand standard
explanations of map
projections?
What can we do to help
them?
[Not to mention other,
more obscure, spatial
representations used in
Geosciences, which
rely heavily on
projective spatial skills.]
from: Hobbs, Bruce E., Winthrop D. Means,
and Paul F. Williams (1976) An Outline of
Structural Geology. New York: John Wiley &
Sons, Inc.
Pitfall #2
Frontispiece from
Geography for Life:
The National Geography
Standards
What is odd
about this
picture?
Frontispiece from
Geography for Life:
The National Geography
Standards
It doesn’t show a
school or a
school activity!
That’s because the
crucial and complex
skill of translating
between the real world
and the representation
(the map) is usually not
taught in school.
The City Park is between which streets?
A and B Streets
B and C Streets
A and C Streets
How many stores are on the map?
0 1 2 3 4 5
For many elementary
school map skills
activities there is no
actual represented
space.
Or even if the
represented space does
exist, the questions can
be answered entirely in
the frame of reference
of the map, without
thinking about the
represented space.
It’s like learning to read musical notation without connecting it to the heard sounds.
?
equals
SK
A
T
PLACE ("reality")
CHILD
REPRESENTATION
(map)
(diagram after Liben, 1997)
Dependent
Variable
(after Liben, 1997)
Many elementary school
map skills curriculum
materials involve tasks
that can be solved entirely
in the frame of reference
of the map, without ever
thinking about the
represented space (the
real world).
Vi deo
Sta rt
bu tton
Map Key
bu tton :
Click for
expl anation
of map
symb ols
Symbo l fo r
wate r
fo unta in
ha s be en
ad ded to
th e ma p.
Wa ter
fountain
i n vide o
Tu rn Righ t arro w
Move Forward
Arro w
Symbo ls that
can b e dra gged
an d dro pped
on to m ap
Tu rn Le ft a rrow
Retu rn to mai n
me nu b utto n
Red dot shows wh ere you are "stan ding ."
Arro w shows wh ich way you a re " l ooking."
Bla ck bal l ma rks wh ere
an incorrect l oca tion was
clicked .
Hint Button: bring s ba ck the red dot and arrow te mpora rily.
Red dot and
arro w are o nly
visi ble wh en
you first sta rt
Are We There
Yet?, or if you
click the "Hin t"
bu tton .
Comp ass
Rose
Gold sta r
ma rks
where ch ild
clicked
th e correct
lo cation.
Red line
Comp ass:
tra ces
Sho ws
th e rou te
th e di rection
fo llowed .
to wa rds whi ch
you are l ooking.
Destination
Pitfall #3
Many important
aspects of the Earth
system are
inherently threedimensional, not flat
like a map nor even
a draped surface
like the Earth’s
surface…..
….. for example the
ocean and its spatial
distribution of
salinity and
temperature.
So we combine
maps with
profiles/sections to
allow students to
explore a threedimensional data
volume to “discover”
3-D structure and
infer flows and
process.
It looks to me, from watching students try the ocean salinity exercise, that
many are making “nonpenetrative errors” in the sense of Kali & Orion (1996):
In ocean salinity
exploration students
can draw any N-S or
E-W profile they
want or maps at any
water depth ….
…. But they can
only see one map or
profile at a time.
How to help learners
grasp internal
structure of 3-D
volume?
Pitfall #4
(from Mayer, 2002, based on software by W. Prothero)
First Training Approach: Look at sketches of possible geological
features: “Pictorial Training”
(after Mayer et al, 2002)
Second training approach: “Strategic Scaffolding”
(after Mayer et al, 2002)
Correct answers out of 5:
Control (no aids)
M=2.36 SD=1.52
M=3.25 SD=1.41
M=2.90 SD=1.78
Both aids
M=3.39 SD=1.41
Analyzing and clearly articulating the
strategies used by experts…..
…. Isn’t necessarily going to be the
strategy that is most effective for
novices.
What happens when we try to communicate outside our cozy
circle of geoscientists and geoscience students?
What
geologists
are
trained to
think
about.
Pitfall #5
What
society
wants to
know
about
Forecast maps combine
two challenging skills or
understandings:
• spatial thinking
• probability
How well does the
intended audience of
decision-makers and
policy-makers understand
such maps?
(from International Research Institute for Climate Prediction:
http://iri.columbia.edu/forecast/net_asmt)
“Suppose that you were
given this forecast map in
January 2003. Based on
this map, how would you
answer the following
question: ‘Which area will
receive a greater amount
of total precipitation for
this forecast period,
Southern California or
Washington State?’ “
(from International Research Institute for Climate Prediction:
http://iri.columbia.edu/forecast/net_asmt)
Participants: 47 students in the Masters program in Environmental Science
and Policy, School of International and Public Affairs, Columbia University
(from Ishikawa, Barnston, Kastens, Louchouarn and Ropelewski , in prep)
Forecast
Subsequently Observed
(from International Research Institute for Climate Prediction:
http://iri.columbia.edu/forecast/net_asmt)
“… how would you characterize the
correspondence between the forecast
and the observation?”
(from Ishikawa, Barnston, Kastens, Louchouarn and Ropelewski , in prep)
“… how would you characterize the
correspondence between the forecast
and the observation?”
“… would you recommend that such
forecasts be used to make decisions
about what crops to plant?”
(from Ishikawa, Barnston, Kastens, Louchouarn and Ropelewski , in prep)
Understanding data (from map or
otherwise)….
….is different from believing data….
… is different from acting upon data.
(from Ishikawa, Barnston, Kastens,
Louchouarn and Ropelewski , in prep)
Pitfalls: Review
• Many students are weak in projective spatial skills
• Students’ early map skills training often lacks any
connection with the real world
• When maps and profiles are combined to explore a data
volume, likelihood of nonpenetrative errors
• Clearly articulating and modelling an approach to mapbased data exploration that works for professionals may
be insufficient for novices
• Understanding is not the same as believing and acting
upon.