topic Re: Reference line for log scale axis in Graphics Programming

Reference line for log scale axis

mnithinshetty — Sun, 05 Sep 2021 11:53:52 GMT

Hi,

I am generating graph using proc template. Customers want graph to be in log scale axis.

So I am using the below line of code in proc template to generate a log scale in X axis and Y axis.

xaxisopts=(label=("<xaxis label>.") type=log logopts=(base=10 tickintervalstyle=logexpand viewmin=0 viewmax=100 tickvalueformat=ratio.).

Then I am formating log scale axis values to 0,1,2,3 as per requirement.

The reference line is to be drawn at 3 for X axis and 2 for Y axis. this is possible in a normal scale graph using referenceline statement proc template.

When I use log scale axis , how do I draw a reference line which is aligning to log scale. I am not very clear how reference line statement behave with log scale axis.

Could you please suggest.

Please see the attachment.

Re: Reference line for log scale axis

PaigeMiller — Sun, 05 Sep 2021 13:36:16 GMT

Many of us will not download Microsoft Office documents because they are a security threat. Please include whatever you are trying to show us directly in your reply, and not as an attachment.

Re: Reference line for log scale axis

GraphGuy — Sun, 05 Sep 2021 13:26:35 GMT

Here's a screen capture of the graphs in the Word document:

Re: Reference line for log scale axis

GraphGuy — Sun, 05 Sep 2021 13:41:35 GMT

Is there any particular reason you're using a custom template? If not, I would recommend using the standard Proc SGplot. Here's an example (using random data, since I don't have your data):

data foo;
do loop = 1 to 200;
x=ranuni(123)*3;
y=ranuni(123)*3;
output;
end;
run;

title "Log plot, with reflines at x=3 and y=2";
proc sgplot data=foo;
scatter x=x y=y;
xaxis values=(0.01, 1, 2, 3) type=log;
yaxis values=(0.01, 1, 2, 3) type=log;
refline 3 / axis=x lineattrs=(pattern=dot color=gray88);
refline 2 / axis=y lineattrs=(pattern=dot color=gray88);
run;

Re: Reference line for log scale axis

DanH_sas — Tue, 07 Sep 2021 15:31:06 GMT

The values specified on the REFLINE statement are treated as LINEAR values, not LOG values. If your goal to put a reference line at LOG(3), then you will need to calculate the value of LOG(3) and use that value on the reference line.

Hope this helps!

Dan