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

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?

> 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.

You should try using an XY-chart.

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.

> 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.

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.

> 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'.

Kind regards
Regina


--
To unsubscribe e-mail to: users+unsubscribe@global.libreoffice.org
Problems? https://www.libreoffice.org/get-help/mailing-lists/how-to-unsubscribe/
Posting guidelines + more: https://wiki.documentfoundation.org/Netiquette
List archive: https://listarchives.libreoffice.org/global/users/
Privacy Policy: https://www.documentfoundation.org/privacy