Geography Reference

In-Depth Information

STEP 2: SCALE THE
X
,
Y
VALUES AND THEN GRAPH THEM

The
x
,
y
values calculated in Step 1 are in kilometers; therefore they are certainly too

large to fit on a piece of paper. As with creating any other map, the values need to

converted to map units by determining a ratio that fits the
x
,
y
values on the sheet of

paper you use (8.5
×
11 inches, or approximately 22
×
33 cm). Scale can be deter-

mined by putting the ground values and map values in the same units, here cm, and

calculating the ratio between the shortest ground value distance and the longest

map value distance.

Determine this value and fill it in here:

Scale factor: ________________________

With the scale factor, convert your original projected values to map units. Use the

table below for those calculations.

Table of Projected Values (Step 2)

Latitude

Longitude

0

°

30

°

60

°

90

°

120

°

150

°

180

°

0

°

0,0

30

°

60

°

90

°

Using a ruler, graph each coordinate pair on the
x
and
y
axis on a separate piece of

paper. The graph should look like the northeastern quadrant of a sinusoidal projec-

tion. When this is completed, label the axis with tick marks that indicate the corre-

sponding degree value from 0

to 90

latitude and 0

to 180

longitude. This is a

°

°

°

°

map projected to a sinusoidal projection.

Questions

1. The sinusoidal projection is an example of an equal area projection. What

are the major differences between this type of projection and conformal pro-

jections?

2. Why do the
x
values lack two-dimensional scaling at 0

longitude in the

°

sinusoidal projection?

3. What are the major differences between the Mercator and sinusoidal projec-

tions? How big is a pole in each projection?

4. Minneapolis/St. Paul is located at approximately -93

longitude, 45

latitude.

°

°

What is the
x
,
y
coordinates in the sinusoidal projection?

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