Re: [libreoffice-users] what's the best way to make charts of spreadsheet data

Hi,

You could also have a look here:

https://www.linuxlinks.com/plottingtools/

Rémy.

Le vendredi 04 janvier 2019 à 22:05 +0000, Dave Howorth a écrit :
> On Fri, 4 Jan 2019 18:54:47 +0100
> Regina Henschel <rb.henschel@t-online.de> wrote:
>
>
> Hi Dave,
>
> Dave Howorth schrieb am 02-Jan-19 um 18:12:
>
> [..]
>
> My spreadsheet data is in columns. Column A is the dates and column
> B is the times. Then ten columns of humidity data and eleven
> columns of temperature data. There are currently just over 5000
> rows of samples.
>
> Making the chart was extremely slow. Every time I changed the Name
> of a line of the chart I had to wait whilst it cycled through
> several steps to make the change. Initially when I removed some
> empty columns from the data range, it took an age to do so. etc.  
>
> Each data item produces an object, which is selectable in edit mode
> of the chart. Your data produce 5000*(10+11)=105000 objects. That
> cannot be fast.
>
> What is the purpose of the chart? You do not need 105000 objects to 
> illustrate something.
>
> With 5000 items in x-direction a lot of them will be on top of
> others. My screen has only 1920 dots width and yours?
>
> Thanks, but this answers itself. If my screen or window has less
> pixels, then why create more objects and try to represent them? The
> chart software should be sampling the data appropriately to the
> resolution.
>
> And sure if I want to explore the detail, then I should be able to
> expand a section of the X-axis. I'm thinking of something like the
> graph module in emoncms, which handles this task with reasonable speed.
>
>
>
> Now I've created the chart and got some reasonable lines across it,
> but what I hope are the dates and times along the X axis are just a
> mess and I've no idea how to make them display usefully.  
>
> I guess you have used a line chart. That x-axis cannot display time 
> units, the smallest unit is day.
> A line chart shows an axis label for each data item. That is likely
> not suitable for your chart.
>
> Correct, I'm using a line chart (i.e. the data I have are a number of
> time series). Thanks for the info about how it behaves.
>
>
> You should try using an XY-chart.
>
> Thanks. Yes, that seems to work better. It's a lot faster as well :)
>
>
> In case you need different positions inside one day, you should make
> a separate column with added date and time values. Then use this
> column for your x-axis.
>
> Yes, I'd created the column and will use it.
>
>
>
> The Y-axis is reasonable from 0 to 120, although it would be nice to
> trim the blank space at the top a bit, since the data can't exceed
> 100.
>
> I haven't found any way to select individual points on the chart to
> display the detailed value of that point or all the values at that
> time.  
>
> Access to single points is only available in edit mode of the chart.
> The information of the point is shown as tooltip.
>
> I don't see any tooltips?
>
>
> You can display the value of data points as data label. Enable it in 
> edit mode in menu Insert > Data Label, or for a distinct point in its 
> context menu "Insert Single Data Label".
>
> In case you use an XY-chart you can generate a text column for labels 
> Such are called 'category' in the dialogs. But there is only one text 
> per row possible.
>
>   Nor do I see a way to temporarily hide individual data lines to
>
> more clearly see other particular lines, for example.  
>
> You can hide the associated column, then the line is removed from the 
> chart. When you show the column, the line is drawn again.
>
> OK, thanks. That works but is a bit laborious.
>
>
>
> If there's any way to do these things with an LO chart, and to
> speed it up, I'd be grateful for any pointers. Or if there are
> better options out there that can read .ods or .csv and display
> charts, that would also be interesting.  
>
> It seems you want to explore your data. Some people have pointed to
> the R-project. But I have never used it. Or you might find suitable
> tools with search term 'data mining'.
>
> Thanks, I'll have a look. I might import the data into my emoncms
> system.
>
>
> Kind regards
> Regina

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