topic Re: Displaying 0 on log axis in Graphics Programming

Displaying 0 on log axis

Leo9 — Mon, 29 Aug 2016 20:32:25 GMT

I want to display "0" as a tick on y-axis. The y-axis in my plot is log axis.

The ticks I have currently are 1E1, 1E2, etc. I am using SAS 9.4M2.

Is there any way to display 0 tick on the y-axis ?

Re: Displaying 0 on log axis

ballardw — Mon, 29 Aug 2016 20:50:16 GMT

You need to provide a bit more detail of the code generating the graph as there may be different options available depending on your approach or procedure used.

Re: Displaying 0 on log axis

Rick_SAS — Mon, 29 Aug 2016 21:01:35 GMT

You can't display 0 on a log-scale axis because log(0) is undefined.

You can display 1E-6, which is 6 units to the left of 1.

You can display 1E-10, which is 10 units to the left of 1.

You can display 1E-16, which is 16 units to the left of 1 and is about the limit of many numerical computations.

Re: Displaying 0 on log axis

Leo9 — Tue, 30 Aug 2016 17:35:20 GMT

Thanks.

Does format works on log axis in 9.4M2 ?

Re: Displaying 0 on log axis

Jay54 — Tue, 30 Aug 2016 20:51:15 GMT

First, let me say I agree with Rick that one should not display a '0' on a log axis. Having said that, if you really want to do that, you can use a format to display the lowest value as '0' as shown below. Or, with SAS 9.40M3, you can use special Unicode values in your format to display the smallest value as "approximately" 0 🙂

data log;
input x y;
datalines;
1 0.1
2 1
3 10
4 10000
5 10000000
;
run;

proc format;
value logzero
0.0001="(*ESC*){unicode '2248'x} 0"
1='1'
1000='1000'
1000000='1000000'
;
run;

ods html close;
ods listing gpath='C:\Work\SASUser' image_dpi=200;
ods graphics / reset width=5in height=3in imagename='LogZero';
proc sgplot data=log;
format y logzero.;
scatter x=x y=y;
yaxis type=log logbase=10 min=0.0001 grid
values=(0.0001 1 1000 1000000) ;
run;

Re: Displaying 0 on log axis

Leo9 — Tue, 30 Aug 2016 22:00:46 GMT

Thank you all for all the answers. I ended up doing the log transformation first and then using linear scale.

I used format to display values I needed.

Re: Displaying 0 on log axis

Rick_SAS — Tue, 30 Aug 2016 23:37:25 GMT

Just to warn you, if you intend to show this graph to someone else, they might notice that it makes no sense.

Re: Displaying 0 on log axis

Leo9 — Wed, 31 Aug 2016 16:45:58 GMT

Thanks Rick. Not using log..it is linear.