コード例 #1
0
ファイル: scene.py プロジェクト: zhangqrl/satpy
    def _slice_datasets(self, dataset_ids, slice_key, new_area, area_only=True):
        """Slice scene in-place for the datasets specified."""
        new_datasets = {}
        datasets = (self[ds_id] for ds_id in dataset_ids)
        for ds, parent_ds in dataset_walker(datasets):
            ds_id = DatasetID.from_dict(ds.attrs)
            # handle ancillary variables
            pres = None
            if parent_ds is not None:
                pres = new_datasets[DatasetID.from_dict(parent_ds.attrs)]
            if ds_id in new_datasets:
                replace_anc(ds, pres)
                continue
            if area_only and ds.attrs.get('area') is None:
                new_datasets[ds_id] = ds
                replace_anc(ds, pres)
                continue

            if not isinstance(slice_key, dict):
                # match dimension name to slice object
                key = dict(zip(ds.dims, slice_key))
            else:
                key = slice_key
            new_ds = ds.isel(**key)
            if new_area is not None:
                new_ds.attrs['area'] = new_area

            new_datasets[ds_id] = new_ds
            if parent_ds is None:
                # don't use `__setitem__` because we don't want this to
                # affect the existing wishlist/dep tree
                self.datasets[ds_id] = new_ds
            else:
                replace_anc(new_ds, pres)
コード例 #2
0
ファイル: scene.py プロジェクト: goodsonr/satpy
    def _resampled_scene(self, new_scn, destination_area, **resample_kwargs):
        """Resample `datasets` to the `destination` area."""
        new_datasets = {}
        datasets = list(new_scn.datasets.values())
        max_area = None
        if isinstance(destination_area, (str, six.text_type)):
            destination_area = get_area_def(destination_area)
        if hasattr(destination_area, 'freeze'):
            try:
                max_area = new_scn.max_area()
                destination_area = destination_area.freeze(max_area)
            except ValueError:
                raise ValueError("No dataset areas available to freeze "
                                 "DynamicAreaDefinition.")

        resamplers = {}
        for dataset, parent_dataset in dataset_walker(datasets):
            ds_id = DatasetID.from_dict(dataset.attrs)
            pres = None
            if parent_dataset is not None:
                pres = new_datasets[DatasetID.from_dict(parent_dataset.attrs)]
            if ds_id in new_datasets:
                replace_anc(dataset, pres)
                continue
            if dataset.attrs.get('area') is None:
                if parent_dataset is None:
                    new_scn.datasets[ds_id] = dataset
                else:
                    replace_anc(dataset, pres)
                continue
            LOG.debug("Resampling %s", ds_id)
            source_area = dataset.attrs['area']
            try:
                slice_x, slice_y = source_area.get_area_slices(
                    destination_area)
                source_area = source_area[slice_y, slice_x]
                dataset = dataset.isel(x=slice_x, y=slice_y)
                assert ('x', source_area.x_size) in dataset.sizes.items()
                assert ('y', source_area.y_size) in dataset.sizes.items()
                dataset.attrs['area'] = source_area
            except NotImplementedError:
                LOG.info("Not reducing data before resampling.")
            if source_area not in resamplers:
                key, resampler = prepare_resampler(source_area,
                                                   destination_area,
                                                   **resample_kwargs)
                resamplers[source_area] = resampler
                self.resamplers[key] = resampler
            kwargs = resample_kwargs.copy()
            kwargs['resampler'] = resamplers[source_area]
            res = resample_dataset(dataset, destination_area, **kwargs)
            new_datasets[ds_id] = res
            if parent_dataset is None:
                new_scn.datasets[ds_id] = res
            else:
                replace_anc(res, pres)