Re: Calling NCL functions from PyNGL

Hi Ravi,

We don't have the WRF functions wrapped via PyNGL, although we do have this in our priority list.

I think the best thing to do is get the Fortran code, which I've attached here, and try wrapping it yourself using f2py:

http://www.scipy.org/F2py

The subroutine of interest is DINTERP3DZ. I think you could remove all the other subroutines if you are not interested in them.

Good luck,

--Mary

On Oct 9, 2012, at 8:46 AM, Ravi Shekhar wrote:

> Hi,
>
> I work with WRF output, and I was wondering what the best way to use a NCL function is from python. Specifically, I have a WRF netcdf file, like the one here: (http://shekhar.info/wrfout_d01_1996-06-11_00_00_00). I would like to convert the winds (U, V, W) from model vertical coordinates (eta) to pressure coordinates. There exists a function to do this, as referenced here: (http://www.ncl.ucar.edu/Document/Functions/Built-in/wrf_interp_3d_z.shtml)
>
> What's the best way to use this function from python? Is there a way to call it? Or do I need to write a NCL script, produce an intermediate output file, and load that from python?
>
> Oh, and one other small question. Is there an equivalent to NCLs addfiles to treat a series of netcdf files as a single unit for the purposes of reading in data? I've been using a loop to assemble my arrays over the record dimension, but I was wondering if there's a better way.
>
> I appreciate any help. Possibly relevant installation info is below the signature. Thanks,
>
> Ravi
>
> --
> Ravi Shekhar
> ravi.shekhar@yale.edu
>
>
> """
> rs7@login-0-1 [10:31:19]> python
> Python 2.7.1 (r271:86832, Sep 24 2012, 21:58:35)
> [GCC 4.1.2 20080704 (Red Hat 4.1.2-48)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import Nio, Ngl
> >>> print(dir(Nio)); print(dir(Ngl))
> ['NIOError', '_C_API', '_Nio', '_Proxy', '__all__', '__array_module__', '__array_module_version__', '__builtins__', '__doc__', '__file__', '__formats__', '__getitem__', '__name__', '__package__', '__setitem__', '__version__', '_builtins', '_fill_value_to_masked', '_get_axis_att', '_get_cf_dims', '_get_masked_array_mode', '_get_option_value', '_is_new_ma', '_known_proxy_classes', '_localatts', '_make_binder', '_masked_to_fill_value', '_proxy', 'assign_value', 'close', 'crdSelect', 'create_variable', 'cs', 'get_value', 'get_variable', 'idxSelect', 'idxsel2xsel', 'inp2csel', 'inp2isel', 'inp2xsel', 'ma', 'np', 'open_file', 'option_defaults', 'options', 'set_option', 'xSelect']
> ['HAS_MA', 'IS_NEW_MA', 'NGGetNCARGEnv', 'NglGaus_p', 'NhlAddAnnotation', 'NhlAddData', 'NhlAddOverlay', 'NhlAppGetDefaultParentId', 'NhlChangeWorkstation', 'NhlClassName', 'NhlClearWorkstation', 'NhlClose', 'NhlCreate', 'NhlDataPolygon', 'NhlDataPolyline', 'NhlDataPolymarker', 'NhlDestroy', 'NhlDraw', 'NhlFATAL', 'NhlFrame', 'NhlFreeColor', 'NhlGETRL', 'NhlGetDouble', 'NhlGetDoubleArray', 'NhlGetFloat', 'NhlGetFloatArray', 'NhlGetGksCi', 'NhlGetInteger', 'NhlGetIntegerArray', 'NhlGetMDDoubleArray', 'NhlGetMDFloatArray', 'NhlGetMDIntegerArray', 'NhlGetNamedColorIndex', 'NhlGetParentWorkstation', 'NhlGetString', 'NhlGetStringArray', 'NhlGetValues', 'NhlGetWorkspaceObjectId', 'NhlINFO', 'NhlInitialize', 'NhlIsAllocatedColor', 'NhlIsApp', 'NhlIsDataComm', 'NhlIsDataItem', 'NhlIsDataSpec', 'NhlIsTransform', 'NhlIsView', 'NhlIsWorkstation', 'NhlLABELONLY', 'NhlLINEANDLABEL', 'NhlLINEONLY', 'NhlNDCPolygon', 'NhlNDCPolyline', 'NhlNDCPolymarker', 'NhlNOERROR', 'NhlNOLINE', 'NhlName', 'NhlNewColor', 'NhlNewDashPattern', 'NhlNewMarker', 'NhlOpen', 'NhlPAppClass', 'NhlPContourPlotClass', 'NhlPDataToNDC', 'NhlPGraphicStyleClass', 'NhlPLogLinPlotClass', 'NhlPNDCToData', 'NhlPNcgmWorkstationClass', 'NhlPOLYGON', 'NhlPOLYLINE', 'NhlPOLYMARKER', 'NhlPPDFWorkstationClass', 'NhlPPSWorkstationClass', 'NhlPScalarFieldClass', 'NhlPXWorkstationClass', 'NhlPcoordArraysClass', 'NhlPlabelBarClass', 'NhlPlegendClass', 'NhlPmapPlotClass', 'NhlPscalarFieldClass', 'NhlPstreamlinePlotClass', 'NhlPtextItemClass', 'NhlPtickMarkClass', 'NhlPtitleClass', 'NhlPvectorFieldClass', 'NhlPvectorPlotClass', 'NhlPxyPlotClass', 'NhlRLClear', 'NhlRLCreate', 'NhlRLDestroy', 'NhlRLIsSet', 'NhlRLSetDouble', 'NhlRLSetFloat', 'NhlRLSetFloatArray', 'NhlRLSetInteger', 'NhlRLSetIntegerArray', 'NhlRLSetMDDoubleArray', 'NhlRLSetMDFloatArray', 'NhlRLSetMDIntegerArray', 'NhlRLSetString', 'NhlRLSetStringArray', 'NhlRLUnSet', 'NhlRemoveAnnotation', 'NhlRemoveData', 'NhlRemoveOverlay', 'NhlSETRL', 'NhlSetColor', 'NhlSetValues', 'NhlUpdateData', 'NhlUpdateWorkstation', 'NhlWARNING', 'PlotIds', 'Resources', 'RscConv', '__all__', '__array_module__', '__array_module_version__', '__builtins__', '__doc__', '__file__', '__name__', '__package__', '__version__', '_add_poly', '_arg_with_scalar', '_check_res_value', '_ck_for_rangs', '_convert_from_ma', '_convert_to_ma', '_crt_dict', '_dfran', '_dptlclskewt', '_dpwskewt', '_dsatlftskewt', '_dshowalskewt', '_dtdaskewt', '_dtmrskewt', '_fill_bw_xy', '_find_cross_xy', '_get_MDdouble_array', '_get_arr_and_force_fv', '_get_arr_and_fv', '_get_double', '_get_double_array', '_get_fill_value', '_get_integer_version', '_get_key_value_keep', '_get_parent_workstation', '_get_res_value_keep', '_get_skewt_msg', '_get_values', '_inputt', '_int_id', '_is_list_or_tuple', '_is_numpy', '_is_numpy_array', '_is_numpy_ma', '_is_numpy_scalar', '_is_python_scalar', '_is_scalar', '_ismissing', '_lst2pobj', '_mask_lambert_conformal', '_ncargpath', '_pobj2lst', '_poly', '_promote_scalar', '_promote_scalar_int32', '_pseq2lst', '_pynglpath_ncarg', '_set_contour_res', '_set_default_msg', '_set_labelbar_res', '_set_legend_res', '_set_map_res', '_set_msg_val_res', '_set_spc_defaults', '_set_spc_res', '_set_streamline_res', '_set_tickmark_res', '_set_vector_res', '_skewtx', '_skewty', '_test_for_mask_lc', 'add_annotation', 'add_cyclic', 'add_new_coord_limits', 'add_poly_wrap', 'add_polygon', 'add_polyline', 'add_polymarker', 'add_text', 'add_text_wrap', 'asciiread', 'betainc', 'blank_plot', 'blank_plot_wrap', 'bndary', 'c_cpcldr', 'c_cprect', 'c_cpseti', 'c_cpsetr', 'c_cssgrid', 'c_dcapethermo', 'c_dgcdist', 'c_dptlclskewt', 'c_dpwskewt', 'c_dsatlftskewt', 'c_dshowalskewt', 'c_dtdaskewt', 'c_dtmrskewt', 'c_hlsrgb', 'c_hsvrgb', 'c_nngetcp', 'c_nngeti', 'c_nngetrd', 'c_nnsetc', 'c_nnseti', 'c_nnsetrd', 'c_pcseti', 'c_pcsetr', 'c_plchhq', 'c_plotif', 'c_rgbhls', 'c_rgbhsv', 'c_rgbyiq', 'c_set', 'c_wmbarbp', 'c_wmgetcp', 'c_wmgetip', 'c_wmgetrp', 'c_wmsetcp', 'c_wmsetip', 'c_wmsetrp', 'c_wmstnmp', 'c_yiqrgb', 'change_workstation', 'chiinv', 'clear_workstation', 'commands', 'contour', 'contour_map', 'contour_map_wrap', 'contour_wrap', 'copy_intp', 'datatondc', 'dcapethermo', 'define_colormap', 'delete_floatArray', 'delete_intp', 'delete_wks', 'destroy', 'dfran_iseq', 'dfran_rseq', 'dim_gbits', 'draw', 'draw_colormap', 'draw_colormap_wrap', 'draw_ndc_grid', 'end', 'first_call_to_open_wks', 'floatArray_getitem', 'floatArray_setitem', 'fplib', 'frame', 'free_color', 'fspan', 'ftcurv', 'ftcurvc', 'ftcurvp', 'ftcurvpc', 'ftcurvpi', 'ftcurvpic', 'gactivate_ws', 'gaus', 'gc_convert', 'gc_dist', 'gc_inout', 'gc_interp', 'gc_qarea', 'gc_tarea', 'gdeactivate_ws', 'gendat', 'generate_2d_array', 'get_MDfloat_array', 'get_MDinteger_array', 'get_bounding_box', 'get_float', 'get_float_array', 'get_integer', 'get_integer_array', 'get_named_color_index', 'get_nglRes_c', 'get_nglRes_f', 'get_nglRes_i', 'get_nglRes_s', 'get_string', 'get_string_array', 'get_workspace_id', 'getbb', 'hlsrgb', 'hlu', 'hsvrgb', 'ind', 'intp_assign', 'intp_value', 'labelbar_ndc', 'labelbar_ndc_wrap', 'legend_ndc', 'legend_ndc_wrap', 'linmsg', 'ma', 'map', 'map_wrap', 'mapgci', 'math', 'maximize_plot', 'maximize_plots', 'merge_colormaps', 'natgrid', 'natgridc', 'ndctodata', 'nearlyequal', 'new_color', 'new_dash_pattern', 'new_floatArray', 'new_intp', 'new_marker', 'nice_cntr_levels', 'nngetp', 'nnsetp', 'normalize_angle', 'numpy', 'open_wks', 'open_wks_wrap', 'os', 'overlay', 'panel', 'panel_wrap', 'pkgs_pth', 'poly_wrap', 'polygon', 'polygon_ndc', 'polyline', 'polyline_ndc', 'polymarker', 'polymarker_ndc', 'pvoid', 'pyngl_version', 'pynglpath', 're', 'regline', 'remove_annotation', 'remove_overlay', 'retrieve_colormap', 'rgbhls', 'rgbhsv', 'rgbyiq', 'set_PCMP04', 'set_color', 'set_nglRes_c', 'set_nglRes_f', 'set_nglRes_i', 'set_nglRes_s', 'set_values', 'site', 'skewt_bkg', 'skewt_plt', 'streamline', 'streamline_map', 'streamline_map_wrap', 'streamline_scalar', 'streamline_scalar_map', 'streamline_scalar_map_wrap', 'streamline_scalar_wrap', 'streamline_wrap', 'string', 'sys', 'text', 'text_ndc', 'text_ndc_wrap', 'text_wrap', 'types', 'update_workstation', 'vector', 'vector_map', 'vector_map_wrap', 'vector_scalar', 'vector_scalar_map', 'vector_scalar_map_wrap', 'vector_scalar_wrap', 'vector_wrap', 'vinth2p', 'wmbarb', 'wmbarbmap', 'wmgetp', 'wmsetp', 'wmstnm', 'xy', 'xy_wrap', 'y', 'y_wrap', 'yiqrgb']
> """
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