[ncl-talk] Issue with creating a bar chart plot
Andrew Kren - NOAA Affiliate
andrew.kren at noaa.gov
Tue Jun 9 15:07:11 MDT 2020
Thanks Rick! Hmm, that is interesting. Could it be that I used an array of
reference lines? This would make some sense as the previous NCL version I
used was 6.5 and didn't upgrade the newer version until last year. I'll try
to dig on my end as well.
On Tue, Jun 9, 2020 at 9:39 AM Rick Brownrigg <brownrig at ucar.edu> wrote:
> (back online)
>
> Hi Andrew,
>
> The errors have to do indirectly with the reference line; If I remove
> those resources, I get a histogram without error messages being thrown. I
> was able to track precisely where in the code things go awry, however I do
> not understand the logic leading up to that point, so I really don't know
> what is the real problem. I unfortunately do not have time to dig into this
> at the level it would require to understand this code (oh for an
> interactive ncl debugger).
>
> There were some changes to gsn_csm.ncl that dealt with reference lines
> around the 2017-2018 time frame, but they seem to be minor and not directly
> related to the code where the miscalculation of box widths occurs, so
> again, its hard to tell.
>
> I wish I had a better answer
> Rick
>
> On Tue, Jun 9, 2020 at 5:46 AM Andrew Kren - NOAA Affiliate <
> andrew.kren at noaa.gov> wrote:
>
>> Hi Rick,
>>
>> Here is a functioning code. I just saved the plotting section and made my
>> own test array, giving the same error. I know I don't need to convert to
>> integer in my min and max calculation but that shouldn't matter.
>>
>> Thanks,
>>
>> On Mon, Jun 8, 2020 at 10:05 PM Rick Brownrigg <brownrig at ucar.edu> wrote:
>>
>>> Offline for the moment -- Andrew if you can send me the data and a
>>> functionally complete script, I'll try to dig into it deeper.
>>>
>>> On Mon, Jun 8, 2020 at 6:31 PM Andrew Kren - NOAA Affiliate <
>>> andrew.kren at noaa.gov> wrote:
>>>
>>>> Hi ncl-talk, Dave, and Rick,
>>>>
>>>> I took both of your guys' advice and here is what I found. I first
>>>> removed tolong but that did not fix it. I then tried dong rounding, as well
>>>> as not doing any conversion, but that still resulted in the error. Then I
>>>> tried commenting out the defining of the bar chart width, but it still came
>>>> up with the same error:
>>>>
>>>> (0) get_bar_arrays: Fatal: The array is not monotonically increasing.
>>>>
>>>> (0) Cannot draw a bar chart.
>>>>
>>>> fatal:Illegal right-hand side type for assignment
>>>>
>>>>
>>>> Here is what I have for my plot section:
>>>>
>>>>
>>>> outfile = "fcst_efuuyr3wd6_top_1_" + (i)
>>>>
>>>>
>>>> length1 = temperature_top(i,0:23)
>>>>
>>>>
>>>> wks = gsn_open_wks("eps",outfile) ; send graphics to PNG file
>>>>
>>>> res = True
>>>>
>>>> res at gsnScale = True
>>>>
>>>> res at gsnFrame = False
>>>>
>>>> res at gsnDraw = True
>>>>
>>>> ; these four resources allow the user to stretch the plot size, and
>>>>
>>>> ; decide exactly where on the page to draw it.
>>>>
>>>>
>>>> ;res at gsnMaximize = True
>>>>
>>>> res at vpXF = 0.01 ; In page coordinates, where to start
>>>>
>>>> res at vpYF = 0.9 ; 0.75 ; the plot
>>>>
>>>> res at vpHeightF = 0.27 ; Changes the aspect ratio
>>>>
>>>> res at vpWidthF = 0.97
>>>>
>>>>
>>>> x_axis = ispan(4,73,3)
>>>>
>>>> x_axis at _FillValue = 999
>>>>
>>>>
>>>>
>>>> res at tiMainString = names_14ers(i) + " 3-Day Forecast (Peak: " +
>>>> hgts_14ers_str(i) + " ft)"
>>>>
>>>> res at gsnXYBarChart = True ; Create bar plot
>>>>
>>>> res at tiMainOffsetYF = 0.006
>>>>
>>>> res at tiMainFontHeightF = 0.02
>>>>
>>>> res at tmXTMode = "Explicit" ; Define own tick mark labels.
>>>>
>>>> res at tmXTValues = x_axis
>>>>
>>>> res at tmXTOn = False ; turn on the top tickmarks
>>>>
>>>> res at tmXBOn = False
>>>>
>>>> res at tmYROn = False
>>>>
>>>> res at tmYRMinorOn = False
>>>>
>>>> res at tmYLOn = False
>>>>
>>>> res at tmYLMinorOn = False
>>>>
>>>> res at tmXTMinorOn = False
>>>>
>>>> res at gsnXRefLine = (/26.5,50.5/)
>>>>
>>>> res at gsnXRefLineColor = (/"gray40","gray40"/)
>>>>
>>>> res at gsnXRefLineDashPatterns = (/2,2/)
>>>>
>>>> res at gsnXRefLineThicknesses = (/1.05,1.05/)
>>>>
>>>> res at tiYAxisOffsetXF = 0.035
>>>>
>>>> res at tiYAxisString = "Temperature"
>>>>
>>>>
>>>> res at tiYAxisFontHeightF = 0.014
>>>>
>>>>
>>>> range_temp = ( tofloat( max(tolong(temperature_top(i,0:23))) -
>>>> min(tolong(temperature_top(i,0:23)))))
>>>>
>>>> max_temp = tofloat(max(tolong(temperature_top(i,0:23)))) +
>>>> (tofloat(max(tolong(temperature_top(i,0:23))) -
>>>> min(tolong(temperature_top(i,0:23))))) * 0.8
>>>>
>>>> min_temp = tofloat(min(tolong(temperature_top(i,0:23)))) -
>>>> (tofloat(max(tolong(temperature_top(i,0:23))) -
>>>> min(tolong(temperature_top(i,0:23))))) * 0.1
>>>>
>>>>
>>>> res at trYMaxF = max_temp ; max value on y-axis
>>>>
>>>> res at trYMinF = min_temp
>>>>
>>>> ; res at gsnXYBarChartBarWidth = 0.75 ; change bar widths
>>>> 0.75 originally
>>>>
>>>> res at gsnXYBarChartColors = "Orange"
>>>>
>>>>
>>>> ; draw 5 separate temperature plots so can make figure big
>>>>
>>>> res at trXMinF = 0 ; adds space on
>>>> either end
>>>>
>>>> res at trXMaxF = 75 ; of the 1st and
>>>> last bars
>>>>
>>>>
>>>> plot = gsn_csm_xy(wks,x_axis,temperature_top(i,0:23),res)
>>>>
>>>>
>>>> My x_axis values are: 4 to 73 by 3
>>>>
>>>> My temperature_top values are:
>>>>
>>>>
>>>> (0) 14
>>>>
>>>> (1) 11
>>>>
>>>> (2) 11
>>>>
>>>> (3) 12
>>>>
>>>> (4) 14
>>>>
>>>> (5) 21
>>>>
>>>> (6) 24
>>>>
>>>> (7) 23
>>>>
>>>> (8) 23
>>>>
>>>> (9) 22
>>>>
>>>> (10) 23
>>>>
>>>> (11) 26
>>>>
>>>> (12) 33
>>>>
>>>> (13) 36
>>>>
>>>> (14) 33
>>>>
>>>> (15) 28
>>>>
>>>> (16) 25
>>>>
>>>> (17) 25
>>>>
>>>> (18) 25
>>>>
>>>> (19) 29
>>>>
>>>> (20) 38
>>>>
>>>> (21) 41
>>>>
>>>> (22) 39
>>>>
>>>> (23) 35
>>>>
>>>>
>>>> I don't understand why the error could still be happening.
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> On Mon, Jun 8, 2020 at 1:40 PM Dave Allured - NOAA Affiliate <
>>>> dave.allured at noaa.gov> wrote:
>>>>
>>>>> Andrew,
>>>>>
>>>>> In the face of unknown behavior, I would try a couple things. First,
>>>>> go back to your original code without my previous suggestion of reversing
>>>>> the axes. That was based on a wrong assumption.
>>>>>
>>>>> 1. I do not understand the purpose of "tolong" here. Data type
>>>>> "long" is normally used only for special purposes in NCL, and there is a
>>>>> chance it is causing trouble. Also, "tolong" would reduce plot accuracy by
>>>>> integer truncation. Try simply removing "tolong", and use
>>>>> temperature_top(i,0:23) directly in the function call. Tofloat, todouble,
>>>>> or toint would be safer alternatives if a conversion function is really
>>>>> needed. If you really want integer rounding here, then you should use the
>>>>> round function to reduce roundoff error.
>>>>>
>>>>> 2. Try completely isolating the plot function from the rest of the
>>>>> program. Write the X and Y arrays to a small Netcdf file. Print (res) and
>>>>> manually recode the printed results into new NCL code lines in a small new
>>>>> test program. Omit all "res" attributes that are not relevant for this
>>>>> plot type. Read the Netcdf file, then call open_wks and gsn_csm_xy, and
>>>>> see if the problem remains. This way, at least you end up with a small
>>>>> reproducer and small data that you can send to the mailing list. HTH.
>>>>>
>>>>>
>>>>> On Mon, Jun 8, 2020 at 7:17 AM Rick Brownrigg <brownrig at ucar.edu>
>>>>> wrote:
>>>>>
>>>>>> I took a quick look at the code. As the errors indicate, it's
>>>>>> happening in a function call get_bart_width(). The calculation of the
>>>>>> variable "delta" is clearly wrong, and that sets off the warning, and
>>>>>> triggers the error later in get_bar_arrays about non-monotonicity (it's
>>>>>> actually not that the array is non-monotonic, it's that it has negative
>>>>>> widths).
>>>>>>
>>>>>> Beyond that, I can not tell why the calculation is wrong,
>>>>>> particularly without the data. That part of the code hasn't changed in some
>>>>>> years, so the v6.5.0 vs v6.6.2 difference is a mystery.
>>>>>>
>>>>>> FWIW...
>>>>>> Rick
>>>>>>
>>>>>>
>>>>>> On Sun, Jun 7, 2020 at 6:58 PM Andrew Kren - NOAA Affiliate via
>>>>>> ncl-talk <ncl-talk at mailman.ucar.edu> wrote:
>>>>>>
>>>>>>> I looked into these things. My x_axis is simply created this way:
>>>>>>>
>>>>>>> x_axis = ispan(4,73,3)
>>>>>>>
>>>>>>>
>>>>>>> And the printed values are correct, increasing by 3 starting at 4,
>>>>>>> 7, etc.
>>>>>>>
>>>>>>>
>>>>>>> So this is still kinda confusing as to why.
>>>>>>>
>>>>>>> On Sun, Jun 7, 2020 at 5:41 PM Dave Allured - NOAA Affiliate <
>>>>>>> dave.allured at noaa.gov> wrote:
>>>>>>>
>>>>>>>> It is only the horizontal axis that needs to be monotonically
>>>>>>>> increasing. That is probably what the error message is about. Naturally,
>>>>>>>> the vertical access may fluctuate anywhere. You might want to check the
>>>>>>>> values of x_axis in your code to see if they make sense.
>>>>>>>>
>>>>>>>> Meanwhile, you should be able to insert a quick fix for x_axis with
>>>>>>>> temporary arrays, something like this. This assumes that x_axis is
>>>>>>>> strictly decreasing rather than increasing. If you change the order, then
>>>>>>>> you must also change the order for the vertical axis data, in the same
>>>>>>>> way. X and Y values are supposed to form ordered pairs to make the bar
>>>>>>>> chart.
>>>>>>>>
>>>>>>>> xplot = x_axis(::-1)
>>>>>>>> yplot = tolong (temperature_top(i,23:0:-1))
>>>>>>>> plot = gsn_csm_xy (wks, xplot, yplot, res)
>>>>>>>>
>>>>>>>> I have no idea what changed to cause a newer NCL version to change
>>>>>>>> from the original behavior.
>>>>>>>>
>>>>>>>>
>>>>>>>> On Sun, Jun 7, 2020 at 1:57 PM Andrew Kren - NOAA Affiliate via
>>>>>>>> ncl-talk <ncl-talk at mailman.ucar.edu> wrote:
>>>>>>>>
>>>>>>>>> Dear ncl-talk,
>>>>>>>>>
>>>>>>>>> I upgraded my NCL to the latest version. Previously I was using
>>>>>>>>> version 6.5. When I upgraded, one of my ncl codes no longer runs
>>>>>>>>> successfully but creates an error code. I am creating a bar chart with
>>>>>>>>> gsn_csm_xy. I originally did not get these errors so I am unsure what could
>>>>>>>>> be going on. I tried to debug the issue but to no avail. Here are my errors:
>>>>>>>>>
>>>>>>>>> (0) get_bar_widths: Warning: The bar width(s) you selected (0.75)
>>>>>>>>> is larger than the smallest delta (-11).
>>>>>>>>>
>>>>>>>>> (0) Defaulting to -11.
>>>>>>>>>
>>>>>>>>> (0) get_bar_arrays: Fatal: The array is not monotonically
>>>>>>>>> increasing.
>>>>>>>>>
>>>>>>>>> (0) Cannot draw a bar chart.
>>>>>>>>>
>>>>>>>>> fatal:Illegal right-hand side type for assignment
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I checked that my array I am plotting has all correct values, and
>>>>>>>>> it does. I didn't know a bar chart had to have monotonically increasing
>>>>>>>>> values. Is there a way around this?
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> The code where it fails is below, in the call to plot.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> plot = gsn_csm_xy(wks,x_axis,tolong(temperature_top(i,0:23)),res)
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> Andrew Kren
>>>>>>>>> Meteorologist
>>>>>>>>> US Dept of Commerce
>>>>>>>>> National Oceanic and Atmospheric Administration
>>>>>>>>> National Weather Service Raleigh, NC
>>>>>>>>> 1005 Capability Drive, Suite 300
>>>>>>>>> Centennial Campus
>>>>>>>>> Raleigh, NC 27606-5226
>>>>>>>>>
>>>>>>>>
>>>>
>>>> --
>>>> Andrew Kren
>>>> Meteorologist
>>>> US Dept of Commerce
>>>> National Oceanic and Atmospheric Administration
>>>> National Weather Service Raleigh, NC
>>>> 1005 Capability Drive, Suite 300
>>>> Centennial Campus
>>>> Raleigh, NC 27606-5226
>>>>
>>>>
>>
>> --
>> Andrew Kren
>> Meteorologist
>> US Dept of Commerce
>> National Oceanic and Atmospheric Administration
>> National Weather Service Raleigh, NC
>> 1005 Capability Drive, Suite 300
>> Centennial Campus
>> Raleigh, NC 27606-5226
>>
>>
--
Andrew Kren
Meteorologist
US Dept of Commerce
National Oceanic and Atmospheric Administration
National Weather Service Raleigh, NC
1005 Capability Drive, Suite 300
Centennial Campus
Raleigh, NC 27606-5226
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