Bar Charts

[jsc]

I've played with this for a while, and searched the forum, but don't see anything about this, exactly.

I'm trying to make a bar chart, but DPlot doesn't what to work with anything except evenly spaced ordinates. Okay, I can trick DPlot into believing that, but how could I go back and add time labels for when the event happened?

Here is a small set of data:

Seconds, On-Load, Off-Load
12/2/2005 8:00:08, 8, 6
12/2/2005 8:00:20, 6, 3
12/2/2005 8:00:34, 11, 7
12/2/2005 8:00:49, 8, 4

Actually, I'd like this to look like this:

Seconds, On-Load, Off-Load
12/2/2005 8:00:08, 8
12/2/2005 8:00:14, , 6
12/2/2005 8:00:20, 6
12/2/2005 8:00:23, , 3
12/2/2005 8:00:34, 11
12/2/2005 8:00:41, , 7
12/2/2005 8:00:49, 8
12/2/2005 8:00:53, , 4

with each bar anchored at the end of the time it happened, and the size of the bar representing the duration (of the preceding event).

Basically, I'd like an XY version of a bar chart, I guess. Excel has a bubble chart, which this could also be, but the bubble concept doesn't seem to tell as much of the story as I would like. And their bar chart doesn't like the x-scale to be anything finer than days.

I plan to embellish the plot with reference lines showing max-On-Load duration, min-Off-Load duration.

If I'm completely off base, ie, something stone cold obvious is staring me in the face and I've missed it, please advise - I'm growing more and more stupid as I age, I think!

Thanks for any suggestions.
Jon

[DPlotAdmin]

First: the equal intervals requirement only applies to multiple data sets. You can have a bar chart with unequal spacing in X if there's only one data set.

I'm not entirely clear on how you want your bars... if you want the first bar, for example, to start at 8:00:08 and extend to 8:00:14 with an amplitude of 6, then you're all set (mostly). After getting rid of the extra commas in your input...

12/2/2005 8:00:08, 8
12/2/2005 8:00:14, 6
12/2/2005 8:00:20, 6
12/2/2005 8:00:23, 3
12/2/2005 8:00:34, 11
12/2/2005 8:00:41, 7
12/2/2005 8:00:49, 8
12/2/2005 8:00:53, 4

copy and paste the above into DPlot, right-click and select "Bar Chart". Right-click again and check "Bars span intervals in X".

The date and time combination is a bit tough to work with on getting the extents just right. I noticed just now that the calendar date formats only allow tick mark intervals in years, months, and days, for example. I'll fix that, but in this case the date is superfluous anyway. To get rid of it, select Edit>Operate on X and use X=24*(X-date(2005,12,2)). Then right-click on any of the values appearing on the X axis and select "Time".

If I've misunderstood what you want please let me know.

[jsc]

Well this is the third time that I entered this reply - I keep exceeding the time-out apparently, as I get distracted.

David, thanks for the response, but I do have two data sets, and I would like them to be able to be colored separately. The data is pretty much sequential, as they alternate on-load--off-load--on-load--off-load, etc., except for breaks in the sequence because something interrupted a cycle.

The bar chart seemed to be the way to go because the height of the bar would indicate a duration, and I could use reference lines to imply exceeding some limits. I guess I could do what I need as an X-Y line graph with symbols, but that just didn't seem to show what I wanted to show, as much. There may be a better way to show this data, but I'm not sure, right now. I do know that I will be looking at data sets with hundreds of events, not just the few shown here, so perhaps a bar graph would get too cluttered, anyway.

[DPlotAdmin]

Actually the restriction about equal intervals doesn't make much sense if all points share the same X values. I'll remove that limitation.