Transform data to a different map projection

From: Jiangfeng Wei <jwei_at_nyahnyahspammersnyahnyah>
Date: Thu, 5 Oct 2006 11:13:01 -0400

Dear all,

I want to transform a data of Lambert Conformal Format to Cylindrical Equidistant projection (regular lat/lon grid). More inflormation on this format can be found here: http://www.cdc.noaa.gov/NARR/format.html. Is there a simple way to transform it in NCL? Can I plot it in Cylindrical Equidistant projection without transforming?

The description of the Lambert Conformal Format data is:

dimensions:
        time = UNLIMITED ; // (365 currently)
        y = 277 ;
        x = 349 ;
        nbnds = 2 ;
variables:
        float lat(y, x) ;
                lat:long_name = "latitude coordinate" ;
                lat:units = "degrees_north" ;
                lat:axis = "Y" ;
                lat:coordinate_defines = "point" ;
                lat:standard_name = "latitude" ;
        float lon(y, x) ;
                lon:units = "degrees_east" ;
                lon:long_name = "longitude coordinate" ;
                lon:axis = "X" ;
                lon:coordinate_defines = "point" ;
                lon:standard_name = "longitude" ;
        float x(x) ;
                x:long_name = "eastward distance from southwest corner of domain in projection coordinates" ;
                x:units = "m" ;
                x:standard_name = "projection_x_coordinate" ;
        float y(y) ;
                y:long_name = "northward distance from southwest corner of domain in projection coordinates" ;
                y:units = "m" ;
                y:standard_name = "projection_y_coordinate" ;
        int Lambert_Conformal ;
                Lambert_Conformal:grid_mapping_name = "lambert_conformal_conic" ;
                Lambert_Conformal:standard_parallel = 50., 50. ;
                Lambert_Conformal:longitude_of_central_meridian = -107. ;
                Lambert_Conformal:latitude_of_projection_origin = 50. ;
                Lambert_Conformal:false_easting = 5632642.22547 ;
                Lambert_Conformal:false_northing = 4612545.65137 ;
        double time(time) ;
                time:units = "hours since 1800-1-1 00:00:0.0" ;
                time:long_name = "analysis time" ;
                time:axis = "T" ;
                time:standard_name = "time" ;
                time:coordinate_defines = "start" ;
                time:delta_t = "0000-00-01 00:00:00" ;
                time:actual_range = 1569072., 1577808. ;
                time:avg_period = "0000-00-01 00:00:00" ;
        double time_bnds(time, nbnds) ;
                time_bnds:long_name = "Time Boundaries" ;
        short acpcp(time, y, x) ;
                acpcp:units = "kg/m^2" ;
                acpcp:long_name = "Daily accumulated convective precipitation at Surface" ;
                acpcp:unpacked_valid_range = 0.f, 60.f ;
                acpcp:precision = 3s ;
                acpcp:actual_range = 0.000995636f, 32.766f ;
                acpcp:missing_value = 32766s ;
                acpcp:add_offset = 32.766f ;
                acpcp:scale_factor = 0.001f ;
                acpcp:valid_range = -32766s, 27235s ;
                acpcp:_FillValue = -32767s ;
                acpcp:GRIB_name = "ACPCP" ;
                acpcp:GRIB_id = 63 ;
                acpcp:var_desc = "convective precipitation accumulation" ;
                acpcp:standard_name = "convective_precipitation_amount" ;
                acpcp:level_desc = "Surface" ;
                acpcp:dataset = "NARR Daily Averages" ;
                acpcp:statistic = "Mean" ;
                acpcp:parent_stat = "Individual Obs" ;
                acpcp:grid_mapping = "Lambert_Conformal" ;
                acpcp:coordinates = "lat lon" ;
                acpcp:cell_methods = "time: mean (of 8 3-hourly values in one day)" ;

// global attributes:
                :standardpar1 = 50. ;
                :standardpar2 = 50.000001 ;
                :centerlon = -107. ;
                :centerlat = 50. ;
                :latcorners = 1.000001f, 0.897945f, 46.3544f, 46.63433f ;
                :loncorners = -145.5f, -68.32005f, -2.569891f, 148.6418f ;
                :stream = "s1" ;

-----------------------------
Jiangfeng Wei
School of Earth and Atmospheric Sciences
Georgia Institute of Technology, Atlanta, Georgia 30332

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Received on Thu Oct 05 2006 - 09:13:01 MDT

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