# graphing techniques

```Ear 101: Graphing Techniques Applied to Earth Science
Graphing Review
A.
B.
Purpose of graphing - to plot data and allow general relationships to be visualized.
Basic X-Y (scatterplot) graph
1.
Axis
a.
Y axis = vertical axis (ordinate)
b.
X axis = horizontal axis (abscissa)
C.
Graph Trends (see attached figures)
1.
Linear Increase / Decrease
2.
Constant
3.
Parabolic (curvilinear) Increase / Decrease
Linear Increase
Constant
Parabolic
D.
Determining Slopes of Lines
1.slope of any line on a graph = rise / run = (Y2 - Y1) / (X2 - X1)
Positive Slope
Negative
Slope
Zero Slope
Undefined Slope
Overview of Graph Types
A.
B.
C.
D.
X-Y Scatterplot Graphs
1.
linear axes
2.
log-linear axes
3.
log-log axes
Bar Graphs
Triangular Graphs (three end-member composition plots)
Polar-Azimuthal Graphs (directional scatter plots)
Example Linear Graph Y = 2X + 4
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0
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Web Hits Per Month
15000
Expected Hits > 13000
10000
5000
0
Jan-98
Example Bar Graph
Jul-98
Jan-99
Jul-99
Jan-00
Jul-00
Jan-01
Log Fit
Polynomial Fit
Linear Fit
In Class Exercise:
1.
Create a climatograph using the following information for Northport, NY.
Located at about 40.90°N 73.35°W. Height about 6m / 19 feet above sea level.
Average Temperature
Jan Feb Mar Apr May Jun
Jul Aug Sep Oct
Nov Dec Year
°F 30.7 32.0 39.7 49.3 59.2 68.2 73.4 72.7 66.2 55.9 46.4 36.0 52.3
```