read grib2 大气数据文件

Grib2Reader.java

    String dataFile = "data/NWP_NMC_T639R/Z_NAFP_C_BABJ_20161108000000_P_CNPC-T639-GMFS-HNEHE-00000.grib2";
    try {
        // open netcdf/grib/grib2 file from argument
        NetcdfDataset gid = NetcdfDataset.openDataset(dataFile);
        // get all grid tables in the file
        List<Variable> variables = gid.getReferencedFile().getVariables();
        for (int i = 0; i < variables.size(); i++) {
            Variable var = variables.get(i);
            if ((!var.isMetadata()) && (!var.getRanges().isEmpty())) {
                System.out.format("%s, %s: %s %s\n", var.getName(), var.getDataType().toString(),var.getRanges().toString(),var.getUnitsString());
//               System.out.print(variables.get(i).getName());
//               System.out.print(", ");
//               System.out.print(variables.get(i).getDataType());
//               System.out.print(": ");
//              // the range of number of the grid
//               System.out.print(variables.get(i).getRanges());
//               System.out.print(" ");
//               // the unit
//               System.out.println(variables.get(i).getUnitsString());

                 //the dimensions of the grid table
                List<Dimension> dimensions = var.getDimensions();
                for (int j = 0; j < dimensions.size(); j++) {
                    Dimension dim = dimensions.get(j);
                    try {
                        // the name of the dimension
                        System.out.print(dim.getName());
                        System.out.print(", ");
                        // the type of the dimension
                        System.out.print(gid.getReferencedFile().findVariable(dim.getName()).findAttribute("_CoordinateAxisType").getStringValue());
                        System.out.print(": ");
                        // the unit of the dimension
                        System.out.println(gid.getReferencedFile().findVariable(dim.getName()).getUnitsString());
                    } catch (Exception e) {
                        System.out.println();
                        continue;
                    }
                }

                // the data in the grid table
                Array dataArray = var.read();
                // calculate the total number of dimension combination
                int dimensionTotal = 1;
                ArrayList<Array> dimensionsData = new ArrayList<Array>();
                for (int k = 0; k < dimensions.size(); k++) {
                    dimensionTotal *= dimensions.get(k).getLength();
                    //preload the dimension value
                    dimensionsData.add(gid.getReferencedFile().findVariable(dimensions.get(k).getName()).read());
                }
                for (int j = 0; j < var.getSize(); j++) {
                    System.out.print(var.getName());
                    System.out.print(", ");
                    // for merging the dimension value
                    int previousDimensionTotal = dimensionTotal;
                    for (int k = 0; k < dimensions.size(); k++) {
                        previousDimensionTotal /= dimensions.get(k).getLength();
                        int arrayNumber = (j / previousDimensionTotal) % (dimensions.get(k).getLength());
                        Variable dimension = gid.getReferencedFile().findVariable(dimensions.get(k).getName());
                        System.out.print(dimension.findAttribute("_CoordinateAxisType").getStringValue());
                        System.out.print(": ");
                        // show the value
                        System.out.print(dimensionsData.get(k).getFloat(arrayNumber));
                        if ((k + 1) != dimensions.size()) {
                            System.out.print(", ");
                        }
                    }
                    System.out.print(" --- ");

                    System.out.print(" ");
                    // print the value
                    System.out.print(dataArray.getFloat(j));
                    System.out.println();
                }
                System.out.println("--------------------------------------------------");
            }
        }
        gid.close();
    } catch (IOException ex) {
        Logger.getLogger(App.class.getName()).log(Level.SEVERE, null, ex);
    }