x-axis should be time-proportional in SAS - time

Question

I need to present a linear x-axis, which means that distance between timepoints needs to be time-proportional. I have done the following code:
/*Produce mean +/- SD plot with line graph*/
proc sgplot data=adpc;
vline hours /response=value group=dose stat=mean limitstat=stderr;
xaxis label='Hours post dose';
yaxis label='Mean +/- SD';
run;
This is the output:
The x-axis has the variable hours which takes the values 0,1,2,3,4,6,8,24 (hours). I think to be time-proportional, means that it should have equal range between the observations. For example, x-axis should be 0,2,4,6,8,10,12,14,16,18,20,22,24 (not sure what time-proportional means).
what should i add?

Answer 1

The issue here is that VLINE is a categorical graph - like a bar graph but with lines. So the X Axis is a categorical axis! The only way to get a categorical axis to be proportional is to not skip any categories.
Better would be to use series or similar, which uses a numeric axis.
Here's an example using made up data (please provide that in the future!) and a HIGHLOW to add your bars.
data adpc;
call streaminit(7);
do dose = 1,5,10,100;
do _i = 1 to 100;
hours = rand('Integer',1,8);
if hours in (5,7) then hours=24;
value = rand('Uniform')*100*log(dose+1);
output;
end;
end;
run;
proc means data=adpc nway;
class dose hours;
var value;
output out=adpc_mean mean(value)=value stderr(value)=std;
run;
data adpc_calc;
set adpc_mean;
std_high = value+std;
std_low = value-std;
run;
proc sgplot data=adpc_calc;
series x=hours y=value/group=dose;
highlow x=hours high=std_high low=std_low/ lowcap=serif highcap=serif;
xaxis values=(1,2,3,4,6,8,24);
run;

Answer 2

Have you tried specifying the values in the XAXIS statement explicitly?
You'll need to list them all but this should give you the idea:
xaxis label='Hours post dose' values = ("0" "2" "4" "6" "8" "10" "12" ... "24");
EDIT: this more simplified version using the fake data from #Joe works well.
data adpc;
call streaminit(7);
do dose = 1,5,10,100;
do _i = 1 to 100;
hours = rand('Integer',1,8);
if hours in (5,7) then hours=24;
value = rand('Uniform')*100*log(dose+1);
output;
end;
end;
run;
proc sgplot data=adpc;
vline hours /response=value group=dose stat=mean limitstat=stderr;
xaxis label='Hours post dose' values = (0 to 24 by 2);
yaxis label='Mean +/- SD';
run;

Answer 3

Add the option type=time to your XAXIS statement. You will also be required to use the values= option to explicitly state the dosage values to be ticked.
Example:
proc sgplot data=have;
vline hours /response=value group=dose stat=mean limitstat=stderr;
xaxis label='Hours post dose'
type=time values=(0 to 4,6,8,24) /* added to xaxis statement */
;
yaxis label='Mean +/- SD';
run;
Full example:
data have;
call streaminit(2021);
do patid = 1 to 500;
dose = int( (patid-1) / (500/4) );
do hours = 0 to 4, 6, 8, 24;
select (dose);
when (0) value = hours/24 * 25;
when (1) value = hours/24 * 45;
when (2) value = ifn (hours<6, hours/6 * 100, 100 - hours/24 * 25);
when (3) value = ifn (hours<6, hours/6 * 250, 250);
otherwise;
end;
base = value;
jitter = rand('uniform') * hours;
value = min(jitter * value, 250);
output;
end;
end;
run;
ods html file='vline.html';
proc sgplot data=have;
vline hours /response=value group=dose stat=mean limitstat=stderr;
xaxis label='Hours post dose' type=time values=(0 to 4,6,8,24);
yaxis label='Mean +/- SD';
run;
ods html close;
Produces