Excel log chart question

I am trying to plot these log10 charts in Excel. I can get a log base 10 chart but I can’t get the chart’s vertical axis to show constant percentage increases. Taking a chart that had a stock price on the vertical axis with values between 20 and 200, the measured distance in change on the vertical axis should remain constant for constant percentage increases in price. For example, if the price increases by 100% then the measured distance change on the vertical axis should be the same for all 100% increases. Examples are \$20 to \$40, \$30 to \$60, \$40 to \$80, \$100 to \$200. If you take a ruler and measure the change on the y-axis, they should be identical. The log paper that Steve used to plot BOFI, CRTO, SKX, SWKS does this, but I was unable to change the y-axis in Excel to do this.

Chris

I am trying to plot these log10 charts in Excel. I can get a log base 10 chart but I can’t get the chart’s vertical axis to show constant percentage increases. Taking a chart that had a stock price on the vertical axis with values between 20 and 200, the measured distance in change on the vertical axis should remain constant for constant percentage increases in price. For example, if the price increases by 100% then the measured distance change on the vertical axis should be the same for all 100% increases. Examples are \$20 to \$40, \$30 to \$60, \$40 to \$80, \$100 to \$200. If you take a ruler and measure the change on the y-axis, they should be identical. The log paper that Steve used to plot BOFI, CRTO, SKX, SWKS does this, but I was unable to change the y-axis in Excel to do this.Chris

Hi Chris, That’s why I use the paper graphs. The picture you get (see that BOFI graph) is so explicit, so clear, and the slope of the line so helpful in visualizing that’s well worth it. Besides which, I have the old-fashioned idea that by drawing the line in yourself it makes you more personally aware of what you are seeing. Finally, I can grab one company’s graph, and another, and another, instantly, right out of my alphabetically-sorted file, whenever I want to, without having to find them on the computer or download them. But as I said I know that is very old-fashioned.

Saul

2 Likes

Chris:

I haven’t used Excel in years but every spreadsheet I do use produces the right Y axis scale for semi-log charts. One way to check is to plot a series that must produce a straight line:

10, 20, 40, 80, 160, 320, 640

http://softwaretimes.com/pics/log.png

Denny Schlesinger

If you don’t get an answer here, you might try