Label Maximum Value Only on Scatterplot

[Scottmeup]

Hi! I've been trying to figure out how to label only a maximum value on a scatterplot by a value from another column in that observation.

eg. with the following:

1 Yellow 3
2 Red 5
3 Blue 16
4 Purple 2
5 Orange 5

I would use column 1 as the x variable, column 3 as the y variable and in the case of "3 Blue 16" I would like the point to be displayed as "Blue" on the plot and the rest of the data points as the default style.

I've tried a few methods (links below) which _do_ find the maximum value, but I haven't been able to make use of that information with a plot.

https://communities.sas.com/t5/General-SAS-Programming/Fastest-way-to-calculate-the-max-of-a-variabl...

https://communities.sas.com/t5/Base-SAS-Programming/Maximum-value-of-a-column-variable/td-p/28751

I've tried storing a local variable with the maximum, and only labelling that through 

if column3 = maximum_value then scatterplot x=column1 y=column2 / datalabel=column2;
else  scatterplot x=column1 y=column2;

But haven't been able to make that work, and thinking about it might not be the best method: the axis are probably not going to align by default if nothing else.

My other approach was to create a column4, and setting it to = column2 if column3's value is the maximum of the column, or blank if that observation's column3 value is not the maximum but I don't seem to be having any success. I don't think I know the syntax well enough.

Does anyone know a way I can dynamically calculate the maximum of column3, store that and use the information to label the relevant plot point with the value for column2 ?

Thanks in advance!

[ballardw]

It would help to show the entire code you are using to generate your graph. The snippet you show implies that you are using GTL and incorporating methods for such a task might require changes to either the template or the sgrender code.

Probably the most flexible to display a single value would be to add an SGANNO= annotate data set but that requires having the appropriate ANNOTATE statements in the template.

[Scottmeup]

Thanks for the reply! I found an approach that worked, I think my use of if / then syntax needs some practice because the same approach was not working until I added do / end.

I'm not familiar with sganno, i'm trying to find an example of case where it is used to apply an annotation only to the maximum value. I don't suppose you would know of an example, or a source I can read?

An approach I have that seems to work, given the variable names from my previous post as 'colorindex', 'color', 'colorscore' in that order, and being in the dataset 'mydata':

*Sort on color score;
proc sort data=mydata;
	by descending score;
run;

*create new variable 'colorwithhighestscore' on row 1 with 'if _n_ = 1 then' 
(known highest value) only, force blank for all other rows with new variable;
data mydata;
	set mydata;
	if _n_ = 1 then
	do;
		colorwithhighestscore = color;
	end;
	else
	do;
		colorwithhighestscore = "";
	end;
run;

*plot using new variable 'colorwithhighestscore' as label;
proc sgplot data=mydata;
	scatter x=colorindex y=colorscore / datalabel=colorwithhighestscore;
run;

I'm not sure this is the best approach, only an approach that I could make work. Feedback is very welcome.

Thanks in advance!

[GraphGuy]

Here's one way to do it, using Proc Gplot, and pointlabel ...

data mydata;
length color $10;
input X color Score;
datalines;
1 Yellow 3
2 Red 5
3 Blue 16
4 Purple 2
5 Orange 5
;
run;

proc sort data=mydata out=mydata;
by descending score;
run;

data mydata; set mydata;
if _n_ = 1 then label_text=color;
run;

symbol1 value=circle height=3pct color=gray55 pointlabel=("#label_text");

axis1 order=(0 to 20 by 5) minor=none offset=(0,0);
axis2 minor=none offset=(3,3);

proc gplot data=mydata;
plot score*x / vaxis=axis1 haxis=axis2;
run;