Source code for satpy.writers.geotiff

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (c) 2015-2019 Satpy developers
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# This file is part of satpy.
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# satpy is free software: you can redistribute it and/or modify it under the
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# Foundation, either version 3 of the License, or (at your option) any later
# version.
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"""GeoTIFF writer objects for creating GeoTIFF files from `DataArray` objects."""

import logging
import numpy as np
from satpy.writers import ImageWriter
# make sure we have rasterio even though we don't use it until trollimage
# saves the image
import rasterio  # noqa

LOG = logging.getLogger(__name__)


[docs]class GeoTIFFWriter(ImageWriter): """Writer to save GeoTIFF images. Basic example from Scene: >>> scn.save_datasets(writer='geotiff') Un-enhanced float geotiff with NaN for fill values: >>> scn.save_datasets(writer='geotiff', dtype=np.float32, enhance=False) To add custom metadata use `tags`: >>> scn.save_dataset(dataset_name, writer='geotiff', ... tags={'offset': 291.8, 'scale': -0.35}) For performance tips on creating geotiffs quickly and making them smaller see the :doc:`faq`. """ GDAL_OPTIONS = ("tfw", "rpb", "rpctxt", "interleave", "tiled", "blockxsize", "blockysize", "nbits", "compress", "num_threads", "predictor", "discard_lsb", "sparse_ok", "jpeg_quality", "jpegtablesmode", "zlevel", "photometric", "alpha", "profile", "bigtiff", "pixeltype", "copy_src_overviews",) def __init__(self, dtype=None, tags=None, **kwargs): """Init the writer.""" super(GeoTIFFWriter, self).__init__(default_config_filename="writers/geotiff.yaml", **kwargs) self.dtype = self.info.get("dtype") if dtype is None else dtype self.tags = self.info.get("tags", None) if tags is None else tags if self.tags is None: self.tags = {} elif not isinstance(self.tags, dict): # if it's coming from a config file self.tags = dict(tuple(x.split("=")) for x in self.tags.split(",")) # GDAL specific settings self.gdal_options = {} for k in self.GDAL_OPTIONS: if k in kwargs or k in self.info: self.gdal_options[k] = kwargs.get(k, self.info[k])
[docs] @classmethod def separate_init_kwargs(cls, kwargs): """Separate the init keyword args.""" # FUTURE: Don't pass Scene.save_datasets kwargs to init and here init_kwargs, kwargs = super(GeoTIFFWriter, cls).separate_init_kwargs( kwargs) for kw in ['dtype', 'tags']: if kw in kwargs: init_kwargs[kw] = kwargs.pop(kw) return init_kwargs, kwargs
[docs] def save_image(self, img, filename=None, dtype=None, fill_value=None, compute=True, keep_palette=False, cmap=None, tags=None, overviews=None, overviews_minsize=256, overviews_resampling=None, include_scale_offset=False, **kwargs): """Save the image to the given ``filename`` in geotiff_ format. Note for faster output and reduced memory usage the ``rasterio`` library must be installed. This writer currently falls back to using ``gdal`` directly, but that will be deprecated in the future. Args: img (xarray.DataArray): Data to save to geotiff. filename (str): Filename to save the image to. Defaults to ``filename`` passed during writer creation. Unlike the creation ``filename`` keyword argument, this filename does not get formatted with data attributes. dtype (numpy.dtype): Numpy data type to save the image as. Defaults to 8-bit unsigned integer (``np.uint8``). If the ``dtype`` argument is provided during writer creation then that will be used as the default. fill_value (int or float): Value to use where data values are NaN/null. If this is specified in the writer configuration file that value will be used as the default. compute (bool): Compute dask arrays and save the image immediately. If ``False`` then the return value can be passed to :func:`~satpy.writers.compute_writer_results` to do the computation. This is useful when multiple images may share input calculations where dask can benefit from not repeating them multiple times. Defaults to ``True`` in the writer by itself, but is typically passed as ``False`` by callers where calculations can be combined. keep_palette (bool): Save palette/color table to geotiff. To be used with images that were palettized with the "palettize" enhancement. Setting this to ``True`` will cause the colormap of the image to be written as a "color table" in the output geotiff and the image data values will represent the index values in to that color table. By default, this will use the colormap used in the "palettize" operation. See the ``cmap`` option for other options. This option defaults to ``False`` and palettized images will be converted to RGB/A. cmap (trollimage.colormap.Colormap or None): Colormap to save as a color table in the output geotiff. See ``keep_palette`` for more information. Defaults to the palette of the provided ``img`` object. The colormap's range should be set to match the index range of the palette (ex. `cmap.set_range(0, len(colors))`). tags (dict): Extra metadata to store in geotiff. overviews (list): The reduction factors of the overviews to include in the image, eg:: scn.save_datasets(overviews=[2, 4, 8, 16]) If provided as an empty list, then levels will be computed as powers of two until the last level has less pixels than `overviews_minsize`. Default is to not add overviews. overviews_minsize (int): Minimum number of pixels for the smallest overview size generated when `overviews` is auto-generated. Defaults to 256. overviews_resampling (str): Resampling method to use when generating overviews. This must be the name of an enum value from :class:`rasterio.enums.Resampling` and only takes effect if the `overviews` keyword argument is provided. Common values include `nearest` (default), `bilinear`, `average`, and many others. See the rasterio documentation for more information. include_scale_offset (bool): Activate inclusion of scale and offset factors in the geotiff to allow retrieving original values from the pixel values. ``False`` by default. .. _geotiff: http://trac.osgeo.org/geotiff/ """ filename = filename or self.get_filename(**img.data.attrs) # Update global GDAL options with these specific ones gdal_options = self.gdal_options.copy() for k in kwargs.keys(): if k in self.GDAL_OPTIONS: gdal_options[k] = kwargs[k] if fill_value is None: # fall back to fill_value from configuration file fill_value = self.info.get('fill_value') dtype = dtype if dtype is not None else self.dtype if dtype is None: dtype = np.uint8 if "alpha" in kwargs: raise ValueError( "Keyword 'alpha' is automatically set based on 'fill_value' " "and should not be specified") if np.issubdtype(dtype, np.floating): if img.mode != "L": raise ValueError("Image must be in 'L' mode for floating " "point geotiff saving") if fill_value is None: LOG.debug("Alpha band not supported for float geotiffs, " "setting fill value to 'NaN'") fill_value = np.nan if keep_palette and cmap is None and img.palette is not None: from satpy.enhancements import create_colormap cmap = create_colormap({'colors': img.palette}) cmap.set_range(0, len(img.palette) - 1) if tags is None: tags = {} tags.update(self.tags) return img.save(filename, fformat='tif', fill_value=fill_value, dtype=dtype, compute=compute, keep_palette=keep_palette, cmap=cmap, tags=tags, include_scale_offset_tags=include_scale_offset, overviews=overviews, overviews_resampling=overviews_resampling, overviews_minsize=overviews_minsize, **gdal_options)