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What's coming in the next release of NCL

The next release of NCL will be version 6.5.0, as we are going to include the much requested "elseif" construct to go with NCL's "if" and "end if" statements.

We will be announcing another new major feature soon. Stay tuned!

We're hoping for a release date of summer 2017.

New Functions

  • exponential_curve_fit - Calculates the coefficients for a simple exponential curve fit of the form ' y = A*exp(B*x)' using least squares.

  • keyword_values - Read a text file that contains keywords and associated values (similar to fortran NAMELIST).

  • regline_weight - Calculates the linear regression coefficient between two series where the dependent (y) variable's values are weighted by some measure of uncertainty (typically, standard deviations) such that the Chi-square goodness-of-fit is minimized.

  • refevt_hamon - Use the Hamon formulation to derive reference evapotranspiration.

    New "elseif" statement added

    This version will have the long-requested "elseif" statement!

    The old way of using "else if" required you to have an "end if" for every "else if" statement:

      a = 5
      if (a.eq.1) then
        a = a + 1
      else if (a.eq.2) then
        a = a + 2
      else if (a.eq.3) then
        a = a + 3
      else if (a.eq.5) then
        a = a + 5
        a = -1
      end if
      end if
      end if
      end if
      print("a = " + a)

    The new way, with the use of "elseif" (no spaces) looks like this:

      a = 5
      if (a.eq.1) then
        a = a + 1
      elseif (a.eq.2) then
        a = a + 2
      elseif (a.eq.3) then
        a = a + 3
      elseif (a.eq.5) then
        a = a + 5
        a = -1
      end if
      print("a = " + a)

    The old way will still work, and both codes above should return:

       a = 10

    New resources

    • gsnShadeFillDotSizeF - allows you to set the dot size if you are using stippling fill when calling gsn_contour_shade.

    • gsnShadeFillScaleF / gsnShadeFillScales - allows you to set the fill scales for pattern fill when calling gsn_contour_shade.

      See example "wavelet_3.ncl" on the Contour effects page.

    • tmGridDrawOrder - Allows you to control the draw order for the tick mark grid lines.

      See example "leg_650_10.ncl" on the Legends page.

    New color table added

    The srip_reanalysis colormap, selected by the SPARC reanalysis intercomparison project group for reanalysis comparisons, was added to the NCL distribution.

    The group carefully selected colors so that groups of reanalyses worked well and so colorblind people could use it. The idea is that papers will have these colors for time-series comparisons. Thanks to Cathy Smith (NOAA/ESRL PSD and CU CIRES) for bringing it to our attention.

    Graphics enhancements

    • get_color_index / get_color_rgba - these functions were enhanced to allow the 3rd argument to be an array of values. This can signficantly speed up the routines if you have a lot of calls to these functions.

      See example table_8.ncl.

    Function and procedure bugs fixed

    • bin_avg - This function expects equal grid spacing for the destination grid. The internal test required exact spacing. However, some grid spacing led to round-off errors which caused the test to fail. More robust testing was used to address this issue.

    • calculate_daily_values / calculate_monthly_values / calculate_segment_values - The documentation for each function has been updated to clarify the supported data structures. The calculate_daily_values / calculate_monthly_values now support 5-dimensional structures of the form: (ncase,time,level,lat,lon) and (time,ncase,level,lat,lon).

    • get_isolines - This function was not correctly checking for out-of-bounds conditions and sometimes returned non-sensical values.

    • natgrid_Wrap - This function was not correctly attaching the coordinate arrays to the return variable (it had the rightmost two dimensions swapped).

    • product - This function now allows types int64, uint, and uint64 to be input.

    Graphics bugs fixed

    • cnLineLabelFormat - Fixed a bug that caused this resource to not be recognized by the gsn_csm contouring routines.

    • gsnYRefLine / gsnXRefLine - Fixed a bug where if you are adding a different number of X and Y reference lines to a plot via these two resources, then you may get a fatal error:

      fatal:Number of dimensions on right hand side do not match number of dimension in left hand side
      fatal:["Execute.c":8640]:Execute: Error occurred at or near line 6014 in file 

      If you need a fix for this problem, download this gsn_csm_640_fix.ncl file and load it from your own script after any other load commands.

    • gsn_add_polyline / gsn_polyline

      • Fixed a bug in which NCL was not always drawing the shortest path between two points on a map.

      • Fixed a bug in which the lines wouldn't be drawn correctly if the precision exceeded that which could be represented by a float.

    • gsn_panel / gsnPanelLabelBar Fixed a bug where if you are running a script that calls gsn_panel to panel XY plots and setting gsnPanelLabelBar to True, then you would get a fatal error:

      fatal:Variable (mono_fill_scl) is undefined
      fatal:["Execute.c":8640]:Execute: Error occurred at or near line 6100 \
         in file $NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl

      The gsnPanelLabelBar resource cannot be applied to XY plots anyway, so the solution is to simply not set this resource. In the next release, NCL will produce a warning instead of exiting with an error.

    • Fix an internal bug in which if you have the NCARG_COLORMAPS environment variable set to a directory that contains files without a "." in them, you would get the following error:

      fatal:Subscript out of range, error in subscript #0
      fatal:An error occurred reading tmp_names
      fatal:["Execute.c":8640]:Execute: Error occurred at or near line 1251 in file /xxx/yyy/lib/ncarg/nclscripts/utilities.ncl
      fatal:["Execute.c":8640]:Execute: Error occurred at or near line 1275 in file /xxx/yyy/lib/ncarg/nclscripts/utilities.ncl

      A work-around is to either not set NCARG_COLORMAPS, or to make sure it points to a directory that has files with a "." in the name. In general, we recommend creating a clean directory that contains only the color maps you want NCL to load, because if you put a bunch of other files in this directory, NCL is going to try to read all of them.

    Other bugs fixed