django/contrib/gis/gdal/geomtype.py

from django.contrib.gis.gdal.error import GDALException


class OGRGeomType:
    "Encapsulate OGR Geometry Types."

    wkb25bit = -2147483648

    # Dictionary of acceptable OGRwkbGeometryType s and their string names.
    _types = {
        0: "Unknown",
        1: "Point",
        2: "LineString",
        3: "Polygon",
        4: "MultiPoint",
        5: "MultiLineString",
        6: "MultiPolygon",
        7: "GeometryCollection",
        100: "None",
        101: "LinearRing",
        102: "PointZ",
        1 + wkb25bit: "Point25D",
        2 + wkb25bit: "LineString25D",
        3 + wkb25bit: "Polygon25D",
        4 + wkb25bit: "MultiPoint25D",
        5 + wkb25bit: "MultiLineString25D",
        6 + wkb25bit: "MultiPolygon25D",
        7 + wkb25bit: "GeometryCollection25D",
    }
    # Reverse type dictionary, keyed by lowercase of the name.
    _str_types = {v.lower(): k for k, v in _types.items()}

    def __init__(self, type_input):
        "Figure out the correct OGR Type based upon the input."
        if isinstance(type_input, OGRGeomType):
            num = type_input.num
        elif isinstance(type_input, str):
            type_input = type_input.lower()
            if type_input == "geometry":
                type_input = "unknown"
            num = self._str_types.get(type_input)
            if num is None:
                raise GDALException('Invalid OGR String Type "%s"' % type_input)
        elif isinstance(type_input, int):
            if type_input not in self._types:
                raise GDALException("Invalid OGR Integer Type: %d" % type_input)
            num = type_input
        else:
            raise TypeError("Invalid OGR input type given.")

        # Setting the OGR geometry type number.
        self.num = num

    def __str__(self):
        "Return the value of the name property."
        return self.name

    def __eq__(self, other):
        """
        Do an equivalence test on the OGR type with the given
        other OGRGeomType, the short-hand string, or the integer.
        """
        if isinstance(other, OGRGeomType):
            return self.num == other.num
        elif isinstance(other, str):
            return self.name.lower() == other.lower()
        elif isinstance(other, int):
            return self.num == other
        else:
            return False

    @property
    def name(self):
        "Return a short-hand string form of the OGR Geometry type."
        return self._types[self.num]

    @property
    def django(self):
        "Return the Django GeometryField for this OGR Type."
        s = self.name.replace("25D", "")
        if s in ("LinearRing", "None"):
            return None
        elif s == "Unknown":
            s = "Geometry"
        elif s == "PointZ":
            s = "Point"
        return s + "Field"

    def to_multi(self):
        """
        Transform Point, LineString, Polygon, and their 25D equivalents
        to their Multi... counterpart.
        """
        if self.name.startswith(("Point", "LineString", "Polygon")):
            self.num += 3