geoseries.py

from distutils.version import LooseVersion
from functools import partial
import json
import warnings

import numpy as np
import pandas as pd
from pandas import Series
from pandas.core.internals import SingleBlockManager

import pyproj
from shapely.geometry.base import BaseGeometry
from shapely.ops import transform

from geopandas.base import GeoPandasBase, _delegate_property
from geopandas.plotting import plot_series

from .array import GeometryDtype, from_shapely
from .base import is_geometry_type


_PYPROJ_VERSION = LooseVersion(pyproj.__version__)


_SERIES_WARNING_MSG = """\
    You are passing non-geometry data to the GeoSeries constructor. Currently,
    it falls back to returning a pandas Series. But in the future, we will start
    to raise a TypeError instead."""


def _geoseries_constructor_with_fallback(data=None, index=None, crs=None, **kwargs):
    """
    A flexible constructor for GeoSeries._constructor, which needs to be able
    to fall back to a Series (if a certain operation does not produce
    geometries)
    """
    try:
        with warnings.catch_warnings():
            warnings.filterwarnings(
                "ignore",
                message=_SERIES_WARNING_MSG,
                category=FutureWarning,
                module="geopandas[.*]",
            )
            return GeoSeries(data=data, index=index, crs=crs, **kwargs)
    except TypeError:
        return Series(data=data, index=index, **kwargs)


class GeoSeries(GeoPandasBase, Series):
    """
    A Series object designed to store shapely geometry objects.

    Parameters
    ----------
    data : array-like, dict, scalar value
        The geometries to store in the GeoSeries.
    index : array-like or Index
        The index for the GeoSeries.
    crs : str, dict (optional)
        Coordinate Reference System of the geometry objects.
    kwargs
        Additional arguments passed to the Series constructor,
         e.g. ``name``.

    Examples
    --------

    >>> from shapely.geometry import Point
    >>> s = geopandas.GeoSeries([Point(1, 1), Point(2, 2), Point(3, 3)])
    >>> s
    0    POINT (1 1)
    1    POINT (2 2)
    2    POINT (3 3)
    dtype: geometry

    See Also
    --------
    GeoDataFrame
    pandas.Series

    """

    _metadata = ["name", "crs"]

    def __new__(cls, data=None, index=None, crs=None, **kwargs):
        # we need to use __new__ because we want to return Series instance
        # instead of GeoSeries instance in case of non-geometry data
        if isinstance(data, SingleBlockManager):
            if isinstance(data.blocks[0].dtype, GeometryDtype):
                if data.blocks[0].ndim == 2:
                    # bug in pandas 0.23 where in certain indexing operations
                    # (such as .loc) a 2D ExtensionBlock (still with 1D values
                    # is created) which results in other failures
                    # bug in pandas <= 0.25.0 when len(values) == 1
                    #   (https://github.com/pandas-dev/pandas/issues/27785)
                    from pandas.core.internals import ExtensionBlock

                    values = data.blocks[0].values
                    block = ExtensionBlock(values, slice(0, len(values), 1), ndim=1)
                    data = SingleBlockManager([block], data.axes[0], fastpath=True)
                self = super(GeoSeries, cls).__new__(cls)
                super(GeoSeries, self).__init__(data, index=index, **kwargs)
                self.crs = crs
                return self
            warnings.warn(_SERIES_WARNING_MSG, FutureWarning, stacklevel=2)
            return Series(data, index=index, **kwargs)

        if isinstance(data, BaseGeometry):
            # fix problem for scalar geometries passed, ensure the list of
            # scalars is of correct length if index is specified
            n = len(index) if index is not None else 1
            data = [data] * n

        name = kwargs.pop("name", None)

        if not is_geometry_type(data):
            # if data is None and dtype is specified (eg from empty overlay
            # test), specifying dtype raises an error:
            # https://github.com/pandas-dev/pandas/issues/26469
            kwargs.pop("dtype", None)
            # Use Series constructor to handle input data
            s = pd.Series(data, index=index, name=name, **kwargs)
            # prevent trying to convert non-geometry objects
            if s.dtype != object:
                if s.empty:
                    s = s.astype(object)
                else:
                    warnings.warn(_SERIES_WARNING_MSG, FutureWarning, stacklevel=2)
                    return s
            # try to convert to GeometryArray, if fails return plain Series
            try:
                data = from_shapely(s.values)
            except TypeError:
                warnings.warn(_SERIES_WARNING_MSG, FutureWarning, stacklevel=2)
                return s
            index = s.index
            name = s.name

        self = super(GeoSeries, cls).__new__(cls)
        super(GeoSeries, self).__init__(data, index=index, name=name, **kwargs)
        self.crs = crs
        self._invalidate_sindex()
        return self

    def __init__(self, *args, **kwargs):
        # need to overwrite Series init to prevent calling it for GeoSeries
        # (doesn't know crs, all work is already done above)
        pass

    def append(self, *args, **kwargs):
        return self._wrapped_pandas_method("append", *args, **kwargs)

    @property
    def geometry(self):
        return self

    @property
    def x(self):
        """Return the x location of point geometries in a GeoSeries"""
        return _delegate_property("x", self)

    @property
    def y(self):
        """Return the y location of point geometries in a GeoSeries"""
        return _delegate_property("y", self)

    @classmethod
    def from_file(cls, filename, **kwargs):
        """Alternate constructor to create a ``GeoSeries`` from a file.

        Can load a ``GeoSeries`` from a file from any format recognized by
        `fiona`. See http://fiona.readthedocs.io/en/latest/manual.html for details.

        Parameters
        ----------
        filename : str
            File path or file handle to read from. Depending on which kwargs
            are included, the content of filename may vary. See
            http://fiona.readthedocs.io/en/latest/README.html#usage for usage details.
        kwargs : key-word arguments
            These arguments are passed to fiona.open, and can be used to
            access multi-layer data, data stored within archives (zip files),
            etc.
        """

        from geopandas import GeoDataFrame

        df = GeoDataFrame.from_file(filename, **kwargs)

        return GeoSeries(df.geometry, crs=df.crs)

    @property
    def __geo_interface__(self):
        """Returns a ``GeoSeries`` as a python feature collection.

        Implements the `geo_interface`. The returned python data structure
        represents the ``GeoSeries`` as a GeoJSON-like ``FeatureCollection``.
        Note that the features will have an empty ``properties`` dict as they
        don't have associated attributes (geometry only).
        """
        from geopandas import GeoDataFrame

        return GeoDataFrame({"geometry": self}).__geo_interface__

    def to_file(self, filename, driver="ESRI Shapefile", **kwargs):
        from geopandas import GeoDataFrame

        data = GeoDataFrame(
            {"geometry": self, "id": self.index.values}, index=self.index
        )
        data.crs = self.crs
        data.to_file(filename, driver, **kwargs)

    #
    # Implement pandas methods
    #

    @property
    def _constructor(self):
        return _geoseries_constructor_with_fallback

    def _wrapped_pandas_method(self, mtd, *args, **kwargs):
        """Wrap a generic pandas method to ensure it returns a GeoSeries"""
        val = getattr(super(GeoSeries, self), mtd)(*args, **kwargs)
        if type(val) == Series:
            val.__class__ = GeoSeries
            val.crs = self.crs
            val._invalidate_sindex()
        return val

    def __getitem__(self, key):
        return self._wrapped_pandas_method("__getitem__", key)

    def sort_index(self, *args, **kwargs):
        return self._wrapped_pandas_method("sort_index", *args, **kwargs)

    def take(self, *args, **kwargs):
        return self._wrapped_pandas_method("take", *args, **kwargs)

    def select(self, *args, **kwargs):
        return self._wrapped_pandas_method("select", *args, **kwargs)

    def __finalize__(self, other, method=None, **kwargs):
        """ propagate metadata from other to self """
        # NOTE: backported from pandas master (upcoming v0.13)
        for name in self._metadata:
            object.__setattr__(self, name, getattr(other, name, None))
        return self

    def isna(self):
        """
        Detect missing values.

        Historically, NA values in a GeoSeries could be represented by
        empty geometric objects, in addition to standard representations
        such as None and np.nan. This behaviour is changed in version 0.6.0,
        and now only actual missing values return True. To detect empty
        geometries, use ``GeoSeries.is_empty`` instead.

        Returns
        -------
        A boolean pandas Series of the same size as the GeoSeries,
        True where a value is NA.

        See Also
        --------
        GeoSeries.notna : inverse of isna
        GeoSeries.is_empty : detect empty geometries
        """
        if self.is_empty.any():
            warnings.warn(
                "GeoSeries.isna() previously returned True for both missing (None) "
                "and empty geometries. Now, it only returns True for missing values. "
                "Since the calling GeoSeries contains empty geometries, the result "
                "has changed compared to previous versions of GeoPandas.\n"
                "Given a GeoSeries 's', you can use 's.is_empty | s.isna()' to get "
                "back the old behaviour.\n\n"
                "To further ignore this warning, you can do: \n"
                "import warnings; warnings.filterwarnings('ignore', 'GeoSeries.isna', "
                "UserWarning)",
                UserWarning,
                stacklevel=2,
            )

        return super(GeoSeries, self).isna()

    def isnull(self):
        """Alias for `isna` method. See `isna` for more detail."""
        return self.isna()

    def notna(self):
        """
        Detect non-missing values.

        Historically, NA values in a GeoSeries could be represented by
        empty geometric objects, in addition to standard representations
        such as None and np.nan. This behaviour is changed in version 0.6.0,
        and now only actual missing values return False. To detect empty
        geometries, use ``~GeoSeries.is_empty`` instead.

        Returns
        -------
        A boolean pandas Series of the same size as the GeoSeries,
        False where a value is NA.

        See Also
        --------
        GeoSeries.isna : inverse of notna
        GeoSeries.is_empty : detect empty geometries
        """
        if self.is_empty.any():
            warnings.warn(
                "GeoSeries.notna() previously returned False for both missing (None) "
                "and empty geometries. Now, it only returns False for missing values. "
                "Since the calling GeoSeries contains empty geometries, the result "
                "has changed compared to previous versions of GeoPandas.\n"
                "Given a GeoSeries 's', you can use '~s.is_empty & s.notna()' to get "
                "back the old behaviour.\n\n"
                "To further ignore this warning, you can do: \n"
                "import warnings; warnings.filterwarnings('ignore', "
                "'GeoSeries.notna', UserWarning)",
                UserWarning,
                stacklevel=2,
            )
        return super(GeoSeries, self).notna()

    def notnull(self):
        """Alias for `notna` method. See `notna` for more detail."""
        return self.notna()

    def fillna(self, value=None, method=None, inplace=False, **kwargs):
        """Fill NA values with a geometry (empty polygon by default).

        "method" is currently not implemented for pandas <= 0.12.
        """
        if value is None:
            value = BaseGeometry()
        return super(GeoSeries, self).fillna(
            value=value, method=method, inplace=inplace, **kwargs
        )

    def __contains__(self, other):
        """Allow tests of the form "geom in s"

        Tests whether a GeoSeries contains a geometry.

        Note: This is not the same as the geometric method "contains".
        """
        if isinstance(other, BaseGeometry):
            return np.any(self.geom_equals(other))
        else:
            return False

    def plot(self, *args, **kwargs):
        """Generate a plot of the geometries in the ``GeoSeries``.

        Wraps the ``plot_series()`` function, and documentation is copied from
        there.
        """
        return plot_series(self, *args, **kwargs)

    plot.__doc__ = plot_series.__doc__

    #
    # Additional methods
    #

    def to_crs(self, crs=None, epsg=None):
        """Returns a ``GeoSeries`` with all geometries transformed to a new
        coordinate reference system.

        Transform all geometries in a GeoSeries to a different coordinate
        reference system.  The ``crs`` attribute on the current GeoSeries must
        be set.  Either ``crs`` in string or dictionary form or an EPSG code
        may be specified for output.

        This method will transform all points in all objects.  It has no notion
        or projecting entire geometries.  All segments joining points are
        assumed to be lines in the current projection, not geodesics.  Objects
        crossing the dateline (or other projection boundary) will have
        undesirable behavior.

        Parameters
        ----------
        crs : dict or str
            Output projection parameters as string or in dictionary form.
        epsg : int
            EPSG code specifying output projection.
        """
        from fiona.crs import from_epsg

        if crs is None and epsg is None:
            raise TypeError("Must set either crs or epsg for output.")

        if self.crs is None:
            raise ValueError(
                "Cannot transform naive geometries.  "
                "Please set a crs on the object first."
            )

        if crs is None:
            try:
                crs = from_epsg(epsg)
            except (TypeError, ValueError):
                raise ValueError("Invalid epsg: {}".format(epsg))

        # skip transformation if the input CRS and output CRS are the exact same
        if _PYPROJ_VERSION >= LooseVersion("2.1.2") and pyproj.CRS.from_user_input(
            self.crs
        ).is_exact_same(pyproj.CRS.from_user_input(crs)):
            return self

        if _PYPROJ_VERSION >= LooseVersion("2.2.0"):
            # if availale, use always_xy=True to preserve GIS axis order
            transformer = pyproj.Transformer.from_crs(self.crs, crs, always_xy=True)
            project = transformer.transform
        elif _PYPROJ_VERSION >= LooseVersion("2.1.0"):
            # use transformer for repeated transformations
            transformer = pyproj.Transformer.from_crs(self.crs, crs)
            project = transformer.transform
        else:
            proj_in = pyproj.Proj(self.crs, preserve_units=True)
            proj_out = pyproj.Proj(crs, preserve_units=True)
            project = partial(pyproj.transform, proj_in, proj_out)
        result = self.apply(lambda geom: transform(project, geom))
        result.__class__ = GeoSeries
        result.crs = crs
        result._invalidate_sindex()
        return result

    def to_json(self, **kwargs):
        """
        Returns a GeoJSON string representation of the GeoSeries.

        Parameters
        ----------
        *kwargs* that will be passed to json.dumps().
        """
        return json.dumps(self.__geo_interface__, **kwargs)

    #
    # Implement standard operators for GeoSeries
    #

    def __xor__(self, other):
        """Implement ^ operator as for builtin set type"""
        return self.symmetric_difference(other)

    def __or__(self, other):
        """Implement | operator as for builtin set type"""
        return self.union(other)

    def __and__(self, other):
        """Implement & operator as for builtin set type"""
        return self.intersection(other)

    def __sub__(self, other):
        """Implement - operator as for builtin set type"""
        return self.difference(other)