Re: datelistplot - log axis for values
- To: mathgroup at smc.vnet.net
- Subject: [mg82825] Re: [mg82806] datelistplot - log axis for values
- From: Carl Woll <carlw at wolfram.com>
- Date: Thu, 1 Nov 2007 05:03:16 -0500 (EST)
- References: <200710311116.GAA22567@smc.vnet.net>
sdw wrote:
>Hi -
>
>Does anyone have a clever way to make datelistplot act like loglistplot and create nice log Y axis vs. dates?
>
>this is not the same as just logging the y variable before plotting - I want the Y axis to show the actual values on a log scale, not the log values on a linear scale
>
>thanks,
>
>Steven
>
>
>
>
One way is to use the internal function used by LogPlot and friends.
First, make Mathematica load the .mx file necessary for LogPlot
functionality:
In[1]:= LogPlot
Out[1]= LogPlot
Next, let's make some data:
data = CountryData["US", {"GDP", All}];
We need to scale the data:
scaledata = data;
scaledata[[All, -1]] = Log[scaledata[[All, -1]]];
Now, we use the internal function Graphics`LogPlotDump`LogScale (this is
why we executed In[1], as this function would be undefined if we hadn't):
ticks = Graphics`LogPlotDump`LogScale[Min[scaledata[[All, -1]]],
Max[scaledata[[All, -1]]]];
Finally, you are ready to make the DateListPlot:
DateListPlot[scaledata, FrameTicks -> {Automatic, ticks, True, None}]
<plot snipped>
Carl Woll
Wolfram Research