Rasterio

-------------------

- Resolve 1744 by adding a ``dtype`` keyword argument to the WarpedVRT
constructor. It allows a user to specify the working data type for the warp
operation and output.
- All cases of deprecated affine right multiplication have been changed to be
forward compatible with affine 3.0. The rasterio tests now pass without
warnings.
- The coordinate transformer used in _base._transform() is now properly
deleted, fixing the memory leak reported in 1713.
- An unavoidable warning about 4-channel colormap entries in
DatasetWriterBase.write_colormap() has been removed.
- All deprecated imports of abstract base classes for collections have been
corrected, eliminating the warnings reported in 1742 and 1764.
- DatasetWriterBase no longer requires that GeoTIFF block sizes be smaller than
the raster size (1760). Block sizes are however checked to ensure that they
are multiples of 16.
- DatasetBase.is_tiled has been made more reliable, fixing 1376.
- Tests have been added to demonstrate that image corruption when writing
block-wise to an image with extra large block sizes (520) is no longer an
issue.

-------------------

- Allow `nan` to be used as fill for float32 datasets in ``rasterize`` (1761).
- A WarpedVRTs destination crs now will default to ``src_crs`` if given, else
to the crs of the source dataset (1755).
- Prevent open's ``sharing`` keyword argument from being pass on to GDAL as a
dataset opening option for create-copy formats like JPEG and PNG (1758).
- Allow complex datasets to be created with a specified nodata value (1747).
- Several Python deprecation warnings have been eliminated (1742).
- When a MemoryFile is opened in write mode, a TypeError will be raised if
integer width and height are not given, fixing 1748.
- Return False when checking equality with objects incompatible with
``CRS.from_user_input()`` (1719)
- Support CRS.from_user_input with other CRS object with ``to_wkt()`` method
(1718)

-------------------

- In ``features.rasterize()``, a shape with an associated value of ``None`` is
now burned in using the function's ``fill`` value and no longer triggers a
TypeError (1738).
- Instances of pytest's tmp_path fixture in tests/test_dataset.py have been
replaced by instances of the older style tmpdir fixture (1697).
- Add support for using GDAL 3.x and PROJ 6 libraries (1700, 1729). Please
note that new features of GDAL 3 and PROJ 6 are not intended to surface.
Geometries and coordinates returned from rasterio keep to the traditional GIS
axis order used by GDAL versions < 3. To do this, rasterio applies a new
private extension function named osr_set_traditional_axis_mapping_strategy to
every OGRSpatialReferenceH object that will be returned from methods in the
_CRS module. Please also note that the binary wheels uploaded to PyPI for
1.0.25 will include GDAL 2.4, *not* GDAL 3.0.
- We were using pytest incorrectly and pytest 5 caught us doing it. This is
now fixed in commit b9f34ee.
- A bug preventing creation of Env instances, and thus dataset opening, when
AWS credentials exist in the environment but boto3 is unavailable has been
fixed (1708).

-------------------

- By default GDAL reuses existing dataset connections when possible.
Multi-threaded programs must avoid this as must programs that re-open
datasets in a different context, such as the overview-seeking program shown
in issue 1504. The sharing keyword argument of rasterio.open() was supposed
to allow users to disable connection reuse on a case-by-case basis, but the
implementation was faulty and connection reuse persisted (1701). This has
been fixed in PR 1704.

-------------------

- Break rio-calc output into chunks of user-specified size to constrain the
amount of memory used (1668).
- Attempts to set attributes of datasets opened in "r" mode now raise a custom
DatasetAttributeError. This exception derives from both RasterioError and
NotImplementedError, which maintains backwards compatibility (1676).
- Block sizes are no longer guarded when creating untiled datasets (1689).
- CRS objects are now hashable and equivalent CRS objects have the same hash
value (1684).
- Allow AWS regions to be specified no matter the signing of requests (1670).
- Add links to API documentation from the Python quickstart guide.
- Use "CRS.from_epsg({})" instead of "CRS.from_dict(init='epsg:{}')" as the
representation for CRS objects that are completely described by an EPSG code.
- Use GDAL's string parsing to get metadata item keys and values, which
accommodates uncommon "KEY:VALUE" forms.

-------------------

- Add JPEG2000 to enums.Compression so that the compression of JP2 files can be
reported (1654).
- Remove mock import from compat and move to test code (1651).