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# Algorithm to Compute the Scaling of a Graph

IP.com Disclosure Number: IPCOM000075969D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 32K

IBM

## Related People

Lawlor, FD: AUTHOR

## Abstract

This is an algorithm for determining the best scaling for a graph from given data points, in order to scale and plot the graph. The algorithm operates within two desirable restrictions: 1) the length (in inches) of each axis is given in order to fit the resulting graph on a page of predefined size; and 2) no more than 9 scale increments per inch to provide readability.

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Algorithm to Compute the Scaling of a Graph

This is an algorithm for determining the best scaling for a graph from given data points, in order to scale and plot the graph. The algorithm operates within two desirable restrictions: 1) the length (in inches) of each axis is given in order to fit the resulting graph on a page of predefined size; and 2) no more than 9 scale increments per inch to provide readability.

Steps 10 and 11 scale the axis by first computing the distance which the axis must span (maximum - minimum data values) at 10, and then at 11 by taking the value of the exponent of the smallest possible increment as the scaling factor of the axis. Thus, the axis is scaled such that each increment is the smallest possible integer value greater than zero.

At 12, the number of increments per inch is calculated such that it is the minimum number to just cover the distance which must be covered by the graph. At 13, the minimum starting label is calculated by dividing the minimum data value by the scale. The starting axis value in user's units is shown at 14, while the value of a one inch increment in user's units is computed at 15.

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