361 lines
12 KiB
Python
361 lines
12 KiB
Python
"""
|
|
The Spatial Reference class, represents OGR Spatial Reference objects.
|
|
|
|
Example:
|
|
>>> from django.contrib.gis.gdal import SpatialReference
|
|
>>> srs = SpatialReference('WGS84')
|
|
>>> print(srs)
|
|
GEOGCS["WGS 84",
|
|
DATUM["WGS_1984",
|
|
SPHEROID["WGS 84",6378137,298.257223563,
|
|
AUTHORITY["EPSG","7030"]],
|
|
TOWGS84[0,0,0,0,0,0,0],
|
|
AUTHORITY["EPSG","6326"]],
|
|
PRIMEM["Greenwich",0,
|
|
AUTHORITY["EPSG","8901"]],
|
|
UNIT["degree",0.01745329251994328,
|
|
AUTHORITY["EPSG","9122"]],
|
|
AUTHORITY["EPSG","4326"]]
|
|
>>> print(srs.proj)
|
|
+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs
|
|
>>> print(srs.ellipsoid)
|
|
(6378137.0, 6356752.3142451793, 298.25722356300003)
|
|
>>> print(srs.projected, srs.geographic)
|
|
False True
|
|
>>> srs.import_epsg(32140)
|
|
>>> print(srs.name)
|
|
NAD83 / Texas South Central
|
|
"""
|
|
from ctypes import byref, c_char_p, c_int
|
|
from enum import IntEnum
|
|
|
|
from django.contrib.gis.gdal.base import GDALBase
|
|
from django.contrib.gis.gdal.error import SRSException
|
|
from django.contrib.gis.gdal.libgdal import GDAL_VERSION
|
|
from django.contrib.gis.gdal.prototypes import srs as capi
|
|
from django.utils.encoding import force_bytes, force_str
|
|
|
|
|
|
class AxisOrder(IntEnum):
|
|
TRADITIONAL = 0
|
|
AUTHORITY = 1
|
|
|
|
|
|
class SpatialReference(GDALBase):
|
|
"""
|
|
A wrapper for the OGRSpatialReference object. According to the GDAL web site,
|
|
the SpatialReference object "provide[s] services to represent coordinate
|
|
systems (projections and datums) and to transform between them."
|
|
"""
|
|
|
|
destructor = capi.release_srs
|
|
|
|
def __init__(self, srs_input="", srs_type="user", axis_order=None):
|
|
"""
|
|
Create a GDAL OSR Spatial Reference object from the given input.
|
|
The input may be string of OGC Well Known Text (WKT), an integer
|
|
EPSG code, a PROJ string, and/or a projection "well known" shorthand
|
|
string (one of 'WGS84', 'WGS72', 'NAD27', 'NAD83').
|
|
"""
|
|
if not isinstance(axis_order, (type(None), AxisOrder)):
|
|
raise ValueError(
|
|
"SpatialReference.axis_order must be an AxisOrder instance."
|
|
)
|
|
self.axis_order = axis_order or AxisOrder.TRADITIONAL
|
|
if srs_type == "wkt":
|
|
self.ptr = capi.new_srs(c_char_p(b""))
|
|
self.import_wkt(srs_input)
|
|
if self.axis_order == AxisOrder.TRADITIONAL and GDAL_VERSION >= (3, 0):
|
|
capi.set_axis_strategy(self.ptr, self.axis_order)
|
|
elif self.axis_order != AxisOrder.TRADITIONAL and GDAL_VERSION < (3, 0):
|
|
raise ValueError("%s is not supported in GDAL < 3.0." % self.axis_order)
|
|
return
|
|
elif isinstance(srs_input, str):
|
|
try:
|
|
# If SRID is a string, e.g., '4326', then make acceptable
|
|
# as user input.
|
|
srid = int(srs_input)
|
|
srs_input = "EPSG:%d" % srid
|
|
except ValueError:
|
|
pass
|
|
elif isinstance(srs_input, int):
|
|
# EPSG integer code was input.
|
|
srs_type = "epsg"
|
|
elif isinstance(srs_input, self.ptr_type):
|
|
srs = srs_input
|
|
srs_type = "ogr"
|
|
else:
|
|
raise TypeError('Invalid SRS type "%s"' % srs_type)
|
|
|
|
if srs_type == "ogr":
|
|
# Input is already an SRS pointer.
|
|
srs = srs_input
|
|
else:
|
|
# Creating a new SRS pointer, using the string buffer.
|
|
buf = c_char_p(b"")
|
|
srs = capi.new_srs(buf)
|
|
|
|
# If the pointer is NULL, throw an exception.
|
|
if not srs:
|
|
raise SRSException(
|
|
"Could not create spatial reference from: %s" % srs_input
|
|
)
|
|
else:
|
|
self.ptr = srs
|
|
|
|
if self.axis_order == AxisOrder.TRADITIONAL and GDAL_VERSION >= (3, 0):
|
|
capi.set_axis_strategy(self.ptr, self.axis_order)
|
|
elif self.axis_order != AxisOrder.TRADITIONAL and GDAL_VERSION < (3, 0):
|
|
raise ValueError("%s is not supported in GDAL < 3.0." % self.axis_order)
|
|
# Importing from either the user input string or an integer SRID.
|
|
if srs_type == "user":
|
|
self.import_user_input(srs_input)
|
|
elif srs_type == "epsg":
|
|
self.import_epsg(srs_input)
|
|
|
|
def __getitem__(self, target):
|
|
"""
|
|
Return the value of the given string attribute node, None if the node
|
|
doesn't exist. Can also take a tuple as a parameter, (target, child),
|
|
where child is the index of the attribute in the WKT. For example:
|
|
|
|
>>> wkt = 'GEOGCS["WGS 84", DATUM["WGS_1984, ... AUTHORITY["EPSG","4326"]]'
|
|
>>> srs = SpatialReference(wkt) # could also use 'WGS84', or 4326
|
|
>>> print(srs['GEOGCS'])
|
|
WGS 84
|
|
>>> print(srs['DATUM'])
|
|
WGS_1984
|
|
>>> print(srs['AUTHORITY'])
|
|
EPSG
|
|
>>> print(srs['AUTHORITY', 1]) # The authority value
|
|
4326
|
|
>>> print(srs['TOWGS84', 4]) # the fourth value in this wkt
|
|
0
|
|
>>> # For the units authority, have to use the pipe symbole.
|
|
>>> print(srs['UNIT|AUTHORITY'])
|
|
EPSG
|
|
>>> print(srs['UNIT|AUTHORITY', 1]) # The authority value for the units
|
|
9122
|
|
"""
|
|
if isinstance(target, tuple):
|
|
return self.attr_value(*target)
|
|
else:
|
|
return self.attr_value(target)
|
|
|
|
def __str__(self):
|
|
"Use 'pretty' WKT."
|
|
return self.pretty_wkt
|
|
|
|
# #### SpatialReference Methods ####
|
|
def attr_value(self, target, index=0):
|
|
"""
|
|
The attribute value for the given target node (e.g. 'PROJCS'). The index
|
|
keyword specifies an index of the child node to return.
|
|
"""
|
|
if not isinstance(target, str) or not isinstance(index, int):
|
|
raise TypeError
|
|
return capi.get_attr_value(self.ptr, force_bytes(target), index)
|
|
|
|
def auth_name(self, target):
|
|
"Return the authority name for the given string target node."
|
|
return capi.get_auth_name(self.ptr, force_bytes(target))
|
|
|
|
def auth_code(self, target):
|
|
"Return the authority code for the given string target node."
|
|
return capi.get_auth_code(self.ptr, force_bytes(target))
|
|
|
|
def clone(self):
|
|
"Return a clone of this SpatialReference object."
|
|
return SpatialReference(capi.clone_srs(self.ptr), axis_order=self.axis_order)
|
|
|
|
def from_esri(self):
|
|
"Morph this SpatialReference from ESRI's format to EPSG."
|
|
capi.morph_from_esri(self.ptr)
|
|
|
|
def identify_epsg(self):
|
|
"""
|
|
This method inspects the WKT of this SpatialReference, and will
|
|
add EPSG authority nodes where an EPSG identifier is applicable.
|
|
"""
|
|
capi.identify_epsg(self.ptr)
|
|
|
|
def to_esri(self):
|
|
"Morph this SpatialReference to ESRI's format."
|
|
capi.morph_to_esri(self.ptr)
|
|
|
|
def validate(self):
|
|
"Check to see if the given spatial reference is valid."
|
|
capi.srs_validate(self.ptr)
|
|
|
|
# #### Name & SRID properties ####
|
|
@property
|
|
def name(self):
|
|
"Return the name of this Spatial Reference."
|
|
if self.projected:
|
|
return self.attr_value("PROJCS")
|
|
elif self.geographic:
|
|
return self.attr_value("GEOGCS")
|
|
elif self.local:
|
|
return self.attr_value("LOCAL_CS")
|
|
else:
|
|
return None
|
|
|
|
@property
|
|
def srid(self):
|
|
"Return the SRID of top-level authority, or None if undefined."
|
|
try:
|
|
return int(self.attr_value("AUTHORITY", 1))
|
|
except (TypeError, ValueError):
|
|
return None
|
|
|
|
# #### Unit Properties ####
|
|
@property
|
|
def linear_name(self):
|
|
"Return the name of the linear units."
|
|
units, name = capi.linear_units(self.ptr, byref(c_char_p()))
|
|
return name
|
|
|
|
@property
|
|
def linear_units(self):
|
|
"Return the value of the linear units."
|
|
units, name = capi.linear_units(self.ptr, byref(c_char_p()))
|
|
return units
|
|
|
|
@property
|
|
def angular_name(self):
|
|
"Return the name of the angular units."
|
|
units, name = capi.angular_units(self.ptr, byref(c_char_p()))
|
|
return name
|
|
|
|
@property
|
|
def angular_units(self):
|
|
"Return the value of the angular units."
|
|
units, name = capi.angular_units(self.ptr, byref(c_char_p()))
|
|
return units
|
|
|
|
@property
|
|
def units(self):
|
|
"""
|
|
Return a 2-tuple of the units value and the units name. Automatically
|
|
determine whether to return the linear or angular units.
|
|
"""
|
|
units, name = None, None
|
|
if self.projected or self.local:
|
|
units, name = capi.linear_units(self.ptr, byref(c_char_p()))
|
|
elif self.geographic:
|
|
units, name = capi.angular_units(self.ptr, byref(c_char_p()))
|
|
if name is not None:
|
|
name = force_str(name)
|
|
return (units, name)
|
|
|
|
# #### Spheroid/Ellipsoid Properties ####
|
|
@property
|
|
def ellipsoid(self):
|
|
"""
|
|
Return a tuple of the ellipsoid parameters:
|
|
(semimajor axis, semiminor axis, and inverse flattening)
|
|
"""
|
|
return (self.semi_major, self.semi_minor, self.inverse_flattening)
|
|
|
|
@property
|
|
def semi_major(self):
|
|
"Return the Semi Major Axis for this Spatial Reference."
|
|
return capi.semi_major(self.ptr, byref(c_int()))
|
|
|
|
@property
|
|
def semi_minor(self):
|
|
"Return the Semi Minor Axis for this Spatial Reference."
|
|
return capi.semi_minor(self.ptr, byref(c_int()))
|
|
|
|
@property
|
|
def inverse_flattening(self):
|
|
"Return the Inverse Flattening for this Spatial Reference."
|
|
return capi.invflattening(self.ptr, byref(c_int()))
|
|
|
|
# #### Boolean Properties ####
|
|
@property
|
|
def geographic(self):
|
|
"""
|
|
Return True if this SpatialReference is geographic
|
|
(root node is GEOGCS).
|
|
"""
|
|
return bool(capi.isgeographic(self.ptr))
|
|
|
|
@property
|
|
def local(self):
|
|
"Return True if this SpatialReference is local (root node is LOCAL_CS)."
|
|
return bool(capi.islocal(self.ptr))
|
|
|
|
@property
|
|
def projected(self):
|
|
"""
|
|
Return True if this SpatialReference is a projected coordinate system
|
|
(root node is PROJCS).
|
|
"""
|
|
return bool(capi.isprojected(self.ptr))
|
|
|
|
# #### Import Routines #####
|
|
def import_epsg(self, epsg):
|
|
"Import the Spatial Reference from the EPSG code (an integer)."
|
|
capi.from_epsg(self.ptr, epsg)
|
|
|
|
def import_proj(self, proj):
|
|
"""Import the Spatial Reference from a PROJ string."""
|
|
capi.from_proj(self.ptr, proj)
|
|
|
|
def import_user_input(self, user_input):
|
|
"Import the Spatial Reference from the given user input string."
|
|
capi.from_user_input(self.ptr, force_bytes(user_input))
|
|
|
|
def import_wkt(self, wkt):
|
|
"Import the Spatial Reference from OGC WKT (string)"
|
|
capi.from_wkt(self.ptr, byref(c_char_p(force_bytes(wkt))))
|
|
|
|
def import_xml(self, xml):
|
|
"Import the Spatial Reference from an XML string."
|
|
capi.from_xml(self.ptr, xml)
|
|
|
|
# #### Export Properties ####
|
|
@property
|
|
def wkt(self):
|
|
"Return the WKT representation of this Spatial Reference."
|
|
return capi.to_wkt(self.ptr, byref(c_char_p()))
|
|
|
|
@property
|
|
def pretty_wkt(self, simplify=0):
|
|
"Return the 'pretty' representation of the WKT."
|
|
return capi.to_pretty_wkt(self.ptr, byref(c_char_p()), simplify)
|
|
|
|
@property
|
|
def proj(self):
|
|
"""Return the PROJ representation for this Spatial Reference."""
|
|
return capi.to_proj(self.ptr, byref(c_char_p()))
|
|
|
|
@property
|
|
def proj4(self):
|
|
"Alias for proj()."
|
|
return self.proj
|
|
|
|
@property
|
|
def xml(self, dialect=""):
|
|
"Return the XML representation of this Spatial Reference."
|
|
return capi.to_xml(self.ptr, byref(c_char_p()), force_bytes(dialect))
|
|
|
|
|
|
class CoordTransform(GDALBase):
|
|
"The coordinate system transformation object."
|
|
destructor = capi.destroy_ct
|
|
|
|
def __init__(self, source, target):
|
|
"Initialize on a source and target SpatialReference objects."
|
|
if not isinstance(source, SpatialReference) or not isinstance(
|
|
target, SpatialReference
|
|
):
|
|
raise TypeError("source and target must be of type SpatialReference")
|
|
self.ptr = capi.new_ct(source._ptr, target._ptr)
|
|
self._srs1_name = source.name
|
|
self._srs2_name = target.name
|
|
|
|
def __str__(self):
|
|
return 'Transform from "%s" to "%s"' % (self._srs1_name, self._srs2_name)
|