Pitfalls [and Possibilities] in the Use of Maps

to Visualize Earth Data and Understand Earth Processes

Kim KastensLamont-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 map-based data exploration that works for professionals may be insufficient for novices

• Understanding is not the same as believing and

acting upon.

(from Downs & Liben, 1991)

Projective spatial skill includes the ability to anticipate the shape of a projection (or shadow) cast by an object held up to a light.

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.

Pitfall #1

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)

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?

Data from Downs & Liben (1991)

Mean number of correct answers selected (out of 6)

Degrees of rotation of object

from vertical30° 60°

90° (flat)

Thin Forms

Male 5.4 5.2 5.1

Female 4.9 4.9 3.3

Thick Forms

Male 1.1 1.3 4.9

Female 0.7 0.9 2.8

from: Hobbs, Bruce E., Winthrop D. Means, and Paul F. Williams (1976) An Outline of Structural Geology. New York: John Wiley & Sons, Inc.

[Not to mention other, more obscure, spatial representations used in Geosciences, which rely heavily on projective spatial skills.]

What is odd about this picture?

Frontispiece fromGeography for Life:The National Geography Standards

Pitfall #2

Frontispiece fromGeography 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.

equals?

It’s like learning to read musical notation without connecting it to the heard sounds.

DependentVariable

PLACE ("reality")

CHILD

REPRESENTATION (map)

(diagram after Liben, 1997)

(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).

Hint Button: brings back the red dot and arrow temporarily.Compass: Shows the direction towards whichyou are looking.

Red dot and arrow are only visible whenyou first start Are We ThereYet? , or if youclick the "Hint" button.

DestinationCompass RoseWater fountain in video

Symbol for waterfountain has beenadded to the map.

Symbols that can be dragged and dropped onto map

Turn Right arrowVideo Red dot shows where you are "standing."

Arrow shows which way you are " looking."

Return to mainmenu buttonStart button Map Key button: Click for explanation of map symbols

Move ForwardArrowTurn Left arrowRed line traces the route followed.

Gold star markswhere child clicked the correct location.

Black ball marks where an incorrect location was clicked.

Pitfall #3

Many important aspects of the Earth system are inherently three-dimensional, 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 three-dimensional 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)

(after Mayer et al, 2002)

First Training Approach: Look at sketches of possible geological features: “Pictorial Training”

(after Mayer et al, 2002)

Second training approach: “Strategic Scaffolding”

Correct answers out of 5:

M=2.36 SD=1.52

M=3.25 SD=1.41

M=2.90 SD=1.78

M=3.39 SD=1.41

Control (no aids)

Both aids

Analyzing and clearly articulating the strategies used by experts…..

…. Isn’t necessarily going to be the strategy that is most effective for novices.

Pitfall #5

What geologists are trained to think about.

What happens when we try to communicate outside our cozy circle of geoscientists and geoscience students?

What society wants to know about

(from International Research Institute for Climate Prediction: http://iri.columbia.edu/forecast/net_asmt)

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?’ “

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)

(from International Research Institute for Climate Prediction: http://iri.columbia.edu/forecast/net_asmt)

Forecast Subsequently Observed

(from Ishikawa, Barnston, Kastens, Louchouarn and Ropelewski , in prep)

“… 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.

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

map-based data exploration that works for professionals may be insufficient for novices

• Understanding is not the same as believing and

acting upon.