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Logarithmic graph

Logarithmic graphs are line graphs with one or both axes in a logarithmic scale. This example is a log/lin graph. The Y axis is a logarithmic scale, the X axis a linear (arithmetic) scale.

Graphics Server lets you draw one or both axes of a line graph in a base 10 logarithmic scale rather than an arithmetic scale, creating a log/lin, log/log, or lin/log graph. Logarithmic axes amplify minor fluctuations and flatten larger ones. In many cases, the logarithmic scale lets you create a more informative comparison of small and large values.

Except for the scales of their axes, logarithmic graphs work exactly like line graphs. They offer the same style options.

• In most ways, you handle logarithmic graphs the same as regular line graphs. You choose from the same style options--lines, symbols, and/or vertical sticks.
  
  
• For lin/log and log/log graphs, you must supply independent X values for all data points.
  
  

Use a logarithmic graph...

• When you have data in logarithmic form.
  
  
• When you want to show a broader range of data than is possible on an arithmetic scale. The arithmetic numbers 10, 100, and 1000, for example, have the logarithms 1, 2, and 3--meaning that these three values would be equally spaced on a logarithmic axis.
  
  
• To demonstrate relative rates of change. On a logarithmic scale, the actual distance representing a given percentage increase or decrease is the same anywhere along the scale, so a continuous percentage change shows as a straight line rather than a curve.
  
  

Other graph types to consider

• You can draw an area graph with a logarithmic Y axis.

In a log/lin graph, both axes are drawn on logarithmic scales.		The lin/log graph has a linear (arithmetic) Y axis and a logarithmic X axis.