cdm/src/main/java/ucar/nc2/NetcdfFileWriter.java
static public NetcdfFileWriter openExisting(String location) throws IOException {
    return new NetcdfFileWriter(null, location, true, null); // dont know the version yet
  }
static public NetcdfFileWriter openExisting(String location) throws IOException {
    return new NetcdfFileWriter(null, location, true, null); // dont know the version yet
  }
Open an existing Netcdf file for writing data. Fill mode is true.
Cannot add new objects, you can only read/write data to existing Variables.

@param location name of existing file to open.
@return existing file that can be written to
@throws java.io.IOException on I/O error