Charting data over time

[bpsmicro]

Not sure if there's an easy way to do this, but here goes...

Let's say I have a column of times, and a column of data points (altitude numbers in my case). I want to make a chart of altitude over time.
*But*, there's a catch: I have series of rows with time values & recorded altitudes, but not only are there gaps in the rows, the intervals aren't consistent (it's nominally one row per minute, but it's not *exactly* one minute).

So just making a simple line graph won't work, because by default Excel doesn't know that to do with the X-axis data in terms of normalizing it. But it seems to me this is the kind of "problem" others encounter that probably have a solution (which may involve something other than Excel, but don't let that stop you )

Brad

[mrice]

Not sure that I completely understand but it does sound like a scatter plot is what you are looking for.

[bpsmicro]

I'll have to play with that a bit more. What I ended up doing, since the data was *supposed* to be in increments of 1 minute, is insert rows for the missing minutes, and massage a bit (due to the nature of the data, precision beyond 1 minute isn't required). I came up with satisfactory results, but I'm going to revisit and look more closely with scatter plats as a learning exercise.

Thanks for the pointer.

Brad.

[shg]

Scatterplots are definitely the way to go -- it bears directly on the physical situation. If various times are missing, the graph interpolates altitudes between them. And no need to insert rows for missing data.

[bpsmicro]

Outstanding! I thought my "solution" was a bit of a hack anyway. It's always good to learn new things. :-)

Thanks;
Brad.

[epowerfan]

Want to do something similar, take 4 data points at various times of day and show a smooth curve that fills in between.

Data is a forecast of high and low tide water level, example:
4am/2.3 ft, 10am/5.9 ft, 2:30pm/4.4 ft, 7:30pm/6.4 ft

New sheet, entered a row of 48 time values for a day in 1/2 hour increments, format time, 1:30 PM
Then entered the data values another row, in the columns of corresponding time. Selected Chart type XY (scatter) and "data points connected by smooth lines without markers".

Where's the smoothed line between points? Can't seem to get the X axis to range properly, like say 5am to 9pm, or the get vertical grid lines on even 1/2 hrs. Here's how it looks like this right now. Maybe I'm almost there?

I'm using Excel 2000. Any advice is appreciated.

[Andy Pope]

Please don't hijack old threads.

Start a new thread, as I'm locking this one, and include a link to any previous posts if relevant.