Plotting more than 32000 points on a chart

I

inquirer

Further to an earlier post, I have about 59000 data points that I want
to plot on an line chart. The points for the x axis are sorted in
ascending order.
I can plot the first 32000 points ok as Series 1 but how can I then plot
points from 32001 on so they plot on the end of series 1? I have treid
defining series 2 as 32001 onwards but these points do not plot on the
end of series 1, rather they start again at the origin.
Any help much appreciated
Thanks
Chris
 
N

NickHK

Is there any visible difference from plotting say every other value instead
of all 59000 points ?

NickHK
 
I

inquirer

NickHK said:
Is there any visible difference from plotting say every other value instead
of all 59000 points ?

NickHK
Thanks for your reply Nick.
No, I have just been looking at that and seems as tho that is what I
will have to do.
To do this, will I have to extract every second point to another column
and then define that as the series or is there another smart way of
defining the series to take every second point?
 
I

inquirer

NickHK said:
Is there any visible difference from plotting say every other value instead
of all 59000 points ?

NickHK
Thanks for your reply Nick.
No, I have just been looking at that and seems as tho that is what I
will have to do.
To do this, will I have to extract every second point to another column
and then define that as the series or is there another smart way of
defining the series to take every second point?
 
I

inquirer

NickHK said:
Is there any visible difference from plotting say every other value instead
of all 59000 points ?

NickHK
Thanks for your reply Nick.
No, I have just been looking at that and seems as tho that is what I
will have to do.
To do this, will I have to extract every second point to another column
and then define that as the series or is there another smart way of
defining the series to take every second point?
 
N

NickHK

You can the fact that the chart will only use visible data in its plot so if
you have a Sequence column, you can apply a filter of "=MOD(A8,2)=0)" to get
every other row.
For that matter, you could maybe get away with every 10th row for a faster
display. Depends on your data and requirements.
Not sure how your situation would work, where you have too many points to
start with.

NickHK
 
P

Peter T

If you don't mind a pair of helper columns try this -

Sample XY data:
A2=0 B2=0
A3=1 B3=B2+0.1

Select A2:B3 and drag the little handle down to say 10002

F1=100 ' every n'th plot

helper columns:
C2 =OFFSET($A$2,(ROW(C2)-ROW($A$2))*$F$1,0)
D2 =OFFSET($B$2,(ROW(D2)-ROW($B$2))*$F$1,0)

Copy C2:D2 down to say 1002+, enough for every 10th point (later you'll need
more for your 59k)

With F1=100 then D103 & below will = 0, doesn't matter how many of these but
maintain at least as many as will ever be needed.

Define these names, Ctr-F3
Name: CatX
=OFFSET($C$2,0,0,COUNTA($B$2:$B$65535)/$F$1+1,1)

Name: Ser1
=OFFSET($D$2,0,0,COUNTA($B$2:$B$65535)/$F$1+1,1)

Make a chart:
Select a couple of cells containing numbers surrounded by blanks
With the chart wizard choose say Line without markers and go straight to
Finish

Select the dummy two point series
In the Edit bar replace the formula

=SERIES(,MyBook.xls!CatX,MyBook.xls!Ser1,1)

You may need to bracket 'MyBook.xls' with apostrophes if any non-standard
characters exist in the xls name (eg space).

Hopefully your Series is now as anticipated.

Change the value in F1 to suit. How much you can increase it (every n'th)
might depend on how spiky your chart is.

Regards,
Peter T
 

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