[ncl-talk] Bar Graph/Histogram plot question

Mary Haley haley at ucar.edu
Tue Apr 25 10:06:20 MDT 2017


Hi Barry,

Those numbers at the top are coming from this line, which sets the main
title for your plot:

  res at tiMainString = str_join(""+x,",")

Remove or comment this line.

In what way do you want to combine the two graphs?  Do you want the bars
side-by-side, or stacked?

As an example, visit this page:

http://www.ncl.ucar.edu/Applications/bar.shtml

and look at:

unique_5.ncl
bar_10.ncl
bar_15.ncl

etc

You can also look at the histogram page, see histo_6.ncl:

http://www.ncl.ucar.edu/Applications/histo.shtml#ex6

--Mary


On Tue, Apr 25, 2017 at 9:46 AM, Barry Lynn <barry.h.lynn at gmail.com> wrote:

> Hi:
>
> I followed Mary's comments to imply that the histogram function plots the
> number of elements within each interval.  Hence, when my obs distribution
> show, for example 227, I created 227 consecutive elements with the value 0,
> and then proceeded through the distribution.
>
> I would like to do the following:
>
> 1) remove the list of numbers at the top of each graph,
>
> 2) Combine the graphs.
>
> The typical approach doesn't work (bottom of code) because there are
> different numbers of x and y.
>
> Thank you for your suggestions.
>
> Barry
> P.S. The code runs stand alone.
>
> On Tue, Apr 25, 2017 at 12:34 AM, Mary Haley <haley at ucar.edu> wrote:
>
>> Hi Barry,
>>
>> The gsn_histogram function takes whatever "bin" values you give it, and
>> counts the number of values that fall in each bin, and then draws this as a
>> bar.
>>
>> If you don't provide any bins, then gsn_histogram will pick "nice" bins
>> for you.
>>
>> The binning happens such that no values are binned in more than one
>> interval.
>>
>> Try running the attached script.
>>
>> In the first plot, I let gsn_histogram pick the bin intervals.
>>
>> The first bin, which is from 1 to 2, will capture all values >= 1 and <
>> 2, the second bin counts all values >=2 and < 3 and so on.  The very last
>> bin, 9 to 10, will count all values >= 9 and <= 10.
>>
>> The second plot I specifically set the bin intervals that I want.
>>
>> In the third plot, instead of counting values that fall in a range, I set
>> an array of discrete values to explicitly count.
>>
>> Hope this helps clear things up.
>>
>> --Mary
>>
>>
>> On Sun, Apr 23, 2017 at 2:23 AM, Barry Lynn <barry.h.lynn at gmail.com>
>> wrote:
>>
>>> Hi:
>>>
>>> I have data specified as below.
>>>
>>> I adapted code from this page:
>>>
>>> https://www.ncl.ucar.edu/Applications/histo.shtml
>>>
>>> Example # 6.
>>>
>>> I set x = "Obs" and y = "Forecast" below.
>>>
>>> The plot I get spreads the obs and forecast data on the x axis (where
>>> the x axis conforms to the value of each).
>>>
>>> The y axis is labeled "Frequency."
>>>
>>> However, this is not a histogram/bar graph I am familiar with.  I am not
>>> sure how frequency is calculated (perhaps out of the total). In any case, I
>>> want to plot the x axis as intervals of 0 to 100 (by 10).  I want the
>>> y-axis to show the values in the obs/forecasts that conform to these
>>> intervals.  (Kaleidagraph can do this easily, but that's not the point
>>> (obviously)).
>>>
>>> I see no such example of how to do this  -- even though this is often
>>> how bar graphs are presented.
>>>
>>> Thank you for your suggestions.
>>>
>>> Barry
>>>
>>>   z = new((/2,dimsizes(x)/),integer)
>>>   z(0,:) = x
>>>   z(1,:) = y
>>>
>>> Percent, Obs, Forecast
>>>
>>>     0    0.0,    0.0,
>>>
>>>     1  227.0,  212.2,
>>>
>>>     4  375.0,  176.7,
>>>
>>>     8  201.0,  141.1,
>>>
>>>    12   62.0,  143.2,
>>>
>>>    18   26.0,  327.5,
>>>
>>>    24    6.0,  199.5,
>>>
>>>    30    1.0,   50.2,
>>>
>>>    36    2.0,    9.4,
>>>
>>>   100    0.0,    4.0,
>>>
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Barry H. Lynn, Ph.D
>>> Senior Lecturer,
>>> The Institute of the Earth Science,
>>> The Hebrew University of Jerusalem,
>>> Givat Ram, Jerusalem 91904, Israel
>>> Tel: 972 547 231 170
>>> Fax: (972)-25662581
>>>
>>> C.E.O, Weather It Is, LTD
>>> Weather and Climate Focus
>>> http://weather-it-is.com
>>> Jerusalem, Israel
>>> Local: 02 930 9525
>>> Cell: 054 7 231 170
>>> Int-IS: x972 2 930 9525
>>> US 914 432 3108 <(914)%20432-3108>
>>>
>>> _______________________________________________
>>> ncl-talk mailing list
>>> ncl-talk at ucar.edu
>>> List instructions, subscriber options, unsubscribe:
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>>>
>>>
>>
>
>
> --
> Barry H. Lynn, Ph.D
> Senior Lecturer,
> The Institute of the Earth Science,
> The Hebrew University of Jerusalem,
> Givat Ram, Jerusalem 91904, Israel
> Tel: 972 547 231 170
> Fax: (972)-25662581
>
> C.E.O, Weather It Is, LTD
> Weather and Climate Focus
> http://weather-it-is.com
> Jerusalem, Israel
> Local: 02 930 9525
> Cell: 054 7 231 170
> Int-IS: x972 2 930 9525
> US 914 432 3108 <(914)%20432-3108>
>
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