legacy/src/main/java/ucar/nc2/dt/TypedDatasetFactory.java
static public TypedDataset open( FeatureType datatype, String location, ucar.nc2.util.CancelTask task, StringBuilder errlog) throws IOException {
    DatasetUrl durl = DatasetUrl.findDatasetUrl(location);
    NetcdfDataset ncd = NetcdfDataset.acquireDataset(durl, true, task);
    return open( datatype, ncd, task, errlog);
  }
static public TypedDataset open( FeatureType datatype, String location, ucar.nc2.util.CancelTask task, StringBuilder errlog) throws IOException {
    DatasetUrl durl = DatasetUrl.findDatasetUrl(location);
    NetcdfDataset ncd = NetcdfDataset.acquireDataset(durl, true, task);
    return open( datatype, ncd, task, errlog);
  }
Open a dataset as a TypedDataset.

@param datatype open this kind of Typed Dataset; may be null, which means search all factories.
If datatype is not null, only return correct TypedDataset (eg PointObsDataset for DataType.POINT).
@param location URL or file location of the dataset
@param task user may cancel
@param errlog place errors here, may not be null
@return a subclass of TypedDataset
@throws java.io.IOException on io error