[ncl-talk] Issue with creating a bar chart plot
Adam Phillips
asphilli at ucar.edu
Fri Jun 12 10:21:51 MDT 2020
Hi Andrew,
Jumping in late here, and I might be off base, but you can draw as many
lines as you want by using gsn_add_polyline:
https://www.ncl.ucar.edu/Document/Graphics/Interfaces/gsn_add_polyline.shtml
Functionality that depends on setting a reference line would be affected by
this though. I would try setting one reference line, and then using
gsn_add_polyline to draw the rest.
Hope that helps!
Adam
On Fri, Jun 12, 2020 at 9:50 AM Andrew Kren - NOAA Affiliate via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:
> All,
>
> I was able to reproduce the error that Rick found with the reference line.
> Is there any way to fix this by still having a reference line?
>
> On Tue, Jun 9, 2020 at 5:07 PM Andrew Kren - NOAA Affiliate <
> andrew.kren at noaa.gov> wrote:
>
>> 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
>>
>>
>
> --
> 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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> ncl-talk at mailman.ucar.edu
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--
Adam Phillips
Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
www.cgd.ucar.edu/staff/asphilli/ 303-497-1726
<http://www.cgd.ucar.edu/staff/asphilli>
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