Subject Matter Content Creation for Second Life Delivery - Teaching through Multi-User Virtual Environments - page 428

that of map projections. Map projections come in
three basic families based on a geometric concep-
tion of how the earth's sphere is converted to a
flat map. The three families are conical, cylindri-
cal, and planar (like a picture of the earth). While
these are common in the map literature and in
map use, cartography, and GIS courses, the stu-
dents can only envision the shapes in 2-D textbooks
or as representations through projection changes
performed by the GIS or cartographic software.
These images are also 2-D and do illustrate how
the lines of longitude and latitude are changed by
map projection, but the flat representation still
limits student understanding.
To overcome this difficulty I again relied on
the building tools of Second Life. In this case the
student was provided with a Mercator map pro-
jection… a map projection in which the lines of
latitude and longitude cross at exactly 90 degree
angles. This projection is typically developed
through the idea of projecting a light from the
center of the earth outward onto a cylinder that
surrounds the earth. The students are asked to

create a flat prim on which to lay the projected
map. The 'wow' factor of producing a map in
Second Life was supplanted by an even greater
reaction when the students were able to create a
sphere and flatten it and place the map on that (a
planar projection). They then produced a cylinder
and placed the texture on the curved part of that
shape. And finally they did the same procedure
for a conical prim (Figure 8). In addition I had the
students place this same map texture on a sphere
to show the students what the lines of longitude
and latitude would look like on the earth.
In this case the students were asked to observe
the nature of the grid lines (longitude and latitude)
as the map texture was literally projected, in 3-D,
inside Second Life. The students were not only
surprised at how effectively they could view the
lines and how they change, but also that they could
walk around the objects and view them as if they
were literally in outer space looking at the earth
(in the case of the sphere at least). The students'
reaction to this visualization was promising, but
the answers to questions posed about the impacts

Figure 8. A perspective of my avatar, Gadget Loon, as he stands amidst the map projections students
have created to illustrate how the lines of latitude and longitude change from one family of projections
to another