#347 "Equal interval" color theming not working as expected [Version 1.6.3 release rev.3576]

closed-fixed
nobody
None
2
2014-11-18
2013-10-30
No

Select data from a database and activate "color theming"

Select "equal interval"

Selecting the "range count" does not work as expected.

For example: with a range count of 5, I expect 5 intervals from MIN(value) to MAX(value). Instead I get 3 intervals.

Selecting the "colour scheme" does not work as expected.

The "colour scheme" has a number appended, which I suppose means "number of colors available to color the intervals". That number should probably not be there and be set to the number of intervals above. Anyway, it is unclear what the difference is between "colorscheme(5)" and "colorscheme(10)" for example.

1 Attachments

Discussion

  • mentaer

    mentaer - 2013-10-30

    Hi again,

    not sure what the problem is. But the number (5 in your image) is indeed the number of ranges/classes that should be generated. Why they are not, that is a qood question, As this method/option has been tested a couple of time, it maybe a data problem (though I am not excluding a bug). Could you check if you have the right data type (integer or double) set for your field/column?

    With respect to the "colorscheme(number)" question: The number, e.g. 5 or 10, indicates how many distinct classes/ranges are displayed differently. I think, if you have, lets say 10 classes/ranges, but you set colorscheme(5), then the 6th-10th class are drawn with repeated colors. That is the number of classes in your dataset/classification must be smaller or equal to the number supported by color scheme.

    hope this helps
    stefan

     
  • mentaer

    mentaer - 2013-10-30
    • status: open --> pending
     
  • michael michaud

    michael michaud - 2013-10-30

    Equal interval problem : I did not check the code, but one explanation could be that the engine hides empty classes (with equals interval, probability to have empty classes is high). What is a bit strange is that class bounds seem to be stretched from one non empty classe to the other.
    About data classes number vs color brewer color number, I think you must see color brewer a a way to choose a "color palette", not "individual colors". You have a "single" green palette with 9 degrees, and it can be applied to a classification with 3, 4, 5, 6, 7, 8, 9, 10 or 11 classes (of course, for 10 and 11 classes, some can't have distinct colors).

     
  • michael michaud

    michael michaud - 2013-11-03
    • Priority: 5 --> 2
     
  • David Tonhofer

    David Tonhofer - 2013-11-07

    Equal interval problem:

    The fact is that there are only 14 values, all below 1000, except the last one which jumps to over 5000. If you now select range count "5", then all the datapoints will be in the first interval. The dialog box indeed shows only the single nonempty interval, the "values below that" interval (empty) and the "values above that" interval (only contains the single maximum value).

    Two remarks on this:

    1. Maybe the rowcount should be displayed to make clear why this happens
    2. Should the last interval start at the maximum of the data set? I think it should end at the maximum, right?
     
  • David Tonhofer

    David Tonhofer - 2013-11-07

    Colorscheme problem:

    I see how the arrangement makes sense. Is there a way to pass the color through the dataset though?

     
  • michael michaud

    michael michaud - 2013-11-10

    David,

    I just made a fix in (r3794+). All the intervals are now represented, even if they contain no occurence. Probably more clear. Let me know what you think.

     
  • michael michaud

    michael michaud - 2013-11-10

    Hmm sorry, you must use PLUS version currently as there is something broken on CORE version.

    Dis not understand your question about colorscheme. What do you mean with "pass the color through dataset".

     
  • michael michaud

    michael michaud - 2014-04-05
     
  • michael michaud

    michael michaud - 2014-04-05

    This ticket will soon be closed. Any reason to keep it opened David ?

     
  • michael michaud

    michael michaud - 2014-04-24
    • status: pending --> closed-fixed
     

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