def __init__(self, srs_code):
"""
Create a new SRS with the given `srs_code` code.
"""
self.srs_code = srs_code
init = _SRS.proj_init.get(srs_code, None)
if init is not None:
self.proj = init()
else:
epsg_num = get_epsg_num(srs_code)
self.proj = Proj(init='epsg:%d' % epsg_num)
def __init__(self, srs_code):
"""
Create a new SRS with the given `srs_code` code.
"""
self.srs_code = srs_code
init = _SRS.proj_init.get(srs_code, None)
if init is not None:
self.proj = init()
else:
epsg_num = get_epsg_num(srs_code)
self.proj = Proj(init='epsg:%d' % epsg_num)
class _SRS(object):
# http://trac.openlayers.org/wiki/SphericalMercator
proj_init = {
'EPSG:4326':
lambda: Proj('+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +over'),
'CRS:84':
lambda: Proj('+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +over'),
}
for _epsg in WEBMERCATOR_EPSG:
proj_init[_epsg] = lambda: Proj(
'+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 '
'+lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m '
'+nadgrids=@null +no_defs +over')
"""
This class represents a Spatial Reference System.
"""
def __init__(self, srs_code):
"""
Create a new SRS with the given `srs_code` code.
"""
self.srs_code = srs_code
init = _SRS.proj_init.get(srs_code, None)
if init is not None:
self.proj = init()
else:
epsg_num = get_epsg_num(srs_code)
self.proj = Proj(init='epsg:%d' % epsg_num)
def transform_to(self, other_srs, points):
"""
:type points: ``(x, y)`` or ``[(x1, y1), (x2, y2), …]``
>>> srs1 = SRS(4326)
>>> srs2 = SRS(900913)
>>> [str(round(x, 5)) for x in srs1.transform_to(srs2, (8.22, 53.15))]
['915046.21432', '7010792.20171']
>>> srs1.transform_to(srs1, (8.25, 53.5))
(8.25, 53.5)
>>> [(str(round(x, 5)), str(round(y, 5))) for x, y in
... srs1.transform_to(srs2, [(8.2, 53.1), (8.22, 53.15), (8.3, 53.2)])]
... #doctest: +NORMALIZE_WHITESPACE
[('912819.8245', '7001516.67745'),
('915046.21432', '7010792.20171'),
('923951.77358', '7020078.53264')]
"""
if self == other_srs:
return points
if isinstance(points[0], (int, float)) and 2 >= len(points) <= 3:
return transform(self.proj, other_srs.proj, *points)
x = [p[0] for p in points]
y = [p[1] for p in points]
transf_pts = transform(self.proj, other_srs.proj, x, y)
return izip(transf_pts[0], transf_pts[1])
def transform_bbox_to(self, other_srs, bbox, with_points=16):
"""
:param with_points: the number of points to use for the transformation.
A bbox transformation with only two or four points may cut off some
parts due to distortions.
>>> ['%.3f' % x for x in
... SRS(4326).transform_bbox_to(SRS(900913), (-180.0, -90.0, 180.0, 90.0))]
['-20037508.343', '-147730762.670', '20037508.343', '147730758.195']
>>> ['%.5f' % x for x in
... SRS(4326).transform_bbox_to(SRS(900913), (8.2, 53.1, 8.3, 53.2))]
['912819.82450', '7001516.67745', '923951.77358', '7020078.53264']
>>> SRS(4326).transform_bbox_to(SRS(4326), (8.25, 53.0, 8.5, 53.75))
(8.25, 53.0, 8.5, 53.75)
"""
if self == other_srs:
return bbox
bbox = self.align_bbox(bbox)
points = generate_envelope_points(bbox, with_points)
transf_pts = self.transform_to(other_srs, points)
result = calculate_bbox(transf_pts)
log_proj.debug('transformed from %r to %r (%s -> %s)' %
(self, other_srs, bbox, result))
return result
def align_bbox(self, bbox):
"""
Align bbox to reasonable values to prevent errors in transformations.
E.g. transformations from EPSG:4326 with lat=90 or -90 will fail, so
we subtract a tiny delta.
At the moment only EPSG:4326 bbox will be modifyed.
>>> bbox = SRS(4326).align_bbox((-180, -90, 180, 90))
>>> -90 < bbox[1] < -89.99999998
True
>>> 90 > bbox[3] > 89.99999998
True
"""
# TODO should not be needed anymore since we transform with +over
# still a few tests depend on the rounding behavior of this
if self.srs_code == 'EPSG:4326':
delta = 0.00000001
(minx, miny, maxx, maxy) = bbox
if abs(miny - -90.0) < 1e-6:
miny = -90.0 + delta
if abs(maxy - 90.0) < 1e-6:
maxy = 90.0 - delta
bbox = minx, miny, maxx, maxy
return bbox
@property
def is_latlong(self):
"""
>>> SRS(4326).is_latlong
True
>>> SRS(31466).is_latlong
False
"""
return self.proj.is_latlong()
@property
def is_axis_order_ne(self):
"""
Returns `True` if the axis order is North, then East
(i.e. y/x or lat/lon).
>>> SRS(4326).is_axis_order_ne
True
>>> SRS('CRS:84').is_axis_order_ne
False
>>> SRS(31468).is_axis_order_ne
True
>>> SRS(31463).is_axis_order_ne
False
>>> SRS(25831).is_axis_order_ne
False
"""
if self.srs_code in base_config().srs.axis_order_ne:
return True
if self.srs_code in base_config().srs.axis_order_en:
return False
if self.is_latlong:
return True
return False
@property
def is_axis_order_en(self):
"""
Returns `True` if the axis order is East then North
(i.e. x/y or lon/lat).
"""
return not self.is_axis_order_ne
def __eq__(self, other):
"""
>>> SRS(4326) == SRS("EpsG:4326")
True
>>> SRS(4326) == SRS("4326")
True
>>> SRS(4326) == SRS(3857)
False
"""
if isinstance(other, _SRS):
return self.proj.srs == other.proj.srs
else:
return NotImplemented
def __ne__(self, other):
"""
>>> SRS(3857) != SRS(3857)
False
>>> SRS(4326) != SRS(900913)
True
"""
equal_result = self.__eq__(other)
if equal_result is NotImplemented:
return NotImplemented
else:
return not equal_result
def __str__(self):
#pylint: disable-msg=E1101
return "SRS %s ('%s')" % (self.srs_code, self.proj.srs)
def __repr__(self):
"""
>>> repr(SRS(4326))
"SRS('EPSG:4326')"
"""
return "SRS('%s')" % (self.srs_code, )
def __hash__(self):
return hash(self.srs_code)
class _SRS(object):
# http://trac.openlayers.org/wiki/SphericalMercator
proj_init = {
'EPSG:4326': lambda: Proj('+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +over'),
'CRS:84': lambda: Proj('+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +over'),
}
for _epsg in WEBMERCATOR_EPSG:
proj_init[_epsg] = lambda: Proj(
'+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 '
'+lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m '
'+nadgrids=@null +no_defs +over')
"""
This class represents a Spatial Reference System.
"""
def __init__(self, srs_code):
"""
Create a new SRS with the given `srs_code` code.
"""
self.srs_code = srs_code
init = _SRS.proj_init.get(srs_code, None)
if init is not None:
self.proj = init()
else:
epsg_num = get_epsg_num(srs_code)
self.proj = Proj(init='epsg:%d' % epsg_num)
def transform_to(self, other_srs, points):
"""
:type points: ``(x, y)`` or ``[(x1, y1), (x2, y2), …]``
>>> srs1 = SRS(4326)
>>> srs2 = SRS(900913)
>>> [str(round(x, 5)) for x in srs1.transform_to(srs2, (8.22, 53.15))]
['915046.21432', '7010792.20171']
>>> srs1.transform_to(srs1, (8.25, 53.5))
(8.25, 53.5)
>>> [(str(round(x, 5)), str(round(y, 5))) for x, y in
... srs1.transform_to(srs2, [(8.2, 53.1), (8.22, 53.15), (8.3, 53.2)])]
... #doctest: +NORMALIZE_WHITESPACE
[('912819.8245', '7001516.67745'),
('915046.21432', '7010792.20171'),
('923951.77358', '7020078.53264')]
"""
if self == other_srs:
return points
if isinstance(points[0], (int, float)) and 2 >= len(points) <= 3:
return transform(self.proj, other_srs.proj, *points)
x = [p[0] for p in points]
y = [p[1] for p in points]
transf_pts = transform(self.proj, other_srs.proj, x, y)
return izip(transf_pts[0], transf_pts[1])
def transform_bbox_to(self, other_srs, bbox, with_points=16):
"""
:param with_points: the number of points to use for the transformation.
A bbox transformation with only two or four points may cut off some
parts due to distortions.
>>> ['%.3f' % x for x in
... SRS(4326).transform_bbox_to(SRS(900913), (-180.0, -90.0, 180.0, 90.0))]
['-20037508.343', '-147730762.670', '20037508.343', '147730758.195']
>>> ['%.5f' % x for x in
... SRS(4326).transform_bbox_to(SRS(900913), (8.2, 53.1, 8.3, 53.2))]
['912819.82450', '7001516.67745', '923951.77358', '7020078.53264']
>>> SRS(4326).transform_bbox_to(SRS(4326), (8.25, 53.0, 8.5, 53.75))
(8.25, 53.0, 8.5, 53.75)
"""
if self == other_srs:
return bbox
bbox = self.align_bbox(bbox)
points = generate_envelope_points(bbox, with_points)
transf_pts = self.transform_to(other_srs, points)
result = calculate_bbox(transf_pts)
log_proj.debug('transformed from %r to %r (%s -> %s)' %
(self, other_srs, bbox, result))
return result
def align_bbox(self, bbox):
"""
Align bbox to reasonable values to prevent errors in transformations.
E.g. transformations from EPSG:4326 with lat=90 or -90 will fail, so
we subtract a tiny delta.
At the moment only EPSG:4326 bbox will be modifyed.
>>> bbox = SRS(4326).align_bbox((-180, -90, 180, 90))
>>> -90 < bbox[1] < -89.99999998
True
>>> 90 > bbox[3] > 89.99999998
True
"""
# TODO should not be needed anymore since we transform with +over
# still a few tests depend on the rounding behavior of this
if self.srs_code == 'EPSG:4326':
delta = 0.00000001
(minx, miny, maxx, maxy) = bbox
if abs(miny - -90.0) < 1e-6:
miny = -90.0 + delta
if abs(maxy - 90.0) < 1e-6:
maxy = 90.0 - delta
bbox = minx, miny, maxx, maxy
return bbox
@property
def is_latlong(self):
"""
>>> SRS(4326).is_latlong
True
>>> SRS(31466).is_latlong
False
"""
return self.proj.is_latlong()
@property
def is_axis_order_ne(self):
"""
Returns `True` if the axis order is North, then East
(i.e. y/x or lat/lon).
>>> SRS(4326).is_axis_order_ne
True
>>> SRS('CRS:84').is_axis_order_ne
False
>>> SRS(31468).is_axis_order_ne
True
>>> SRS(31463).is_axis_order_ne
False
>>> SRS(25831).is_axis_order_ne
False
"""
if self.srs_code in base_config().srs.axis_order_ne:
return True
if self.srs_code in base_config().srs.axis_order_en:
return False
if self.is_latlong:
return True
return False
@property
def is_axis_order_en(self):
"""
Returns `True` if the axis order is East then North
(i.e. x/y or lon/lat).
"""
return not self.is_axis_order_ne
def __eq__(self, other):
"""
>>> SRS(4326) == SRS("EpsG:4326")
True
>>> SRS(4326) == SRS("4326")
True
>>> SRS(4326) == SRS(900913)
False
>>> SRS(3857) == SRS(900913)
True
>>> SRS(900913) == SRS(3857)
True
"""
if isinstance(other, _SRS):
if (self.srs_code in WEBMERCATOR_EPSG
and other.srs_code in WEBMERCATOR_EPSG):
return True
return self.proj.srs == other.proj.srs
else:
return NotImplemented
def __ne__(self, other):
"""
>>> SRS(900913) != SRS(900913)
False
>>> SRS(4326) != SRS(900913)
True
"""
equal_result = self.__eq__(other)
if equal_result is NotImplemented:
return NotImplemented
else:
return not equal_result
def __str__(self):
#pylint: disable-msg=E1101
return "SRS %s ('%s')" % (self.srs_code, self.proj.srs)
def __repr__(self):
"""
>>> repr(SRS(4326))
"SRS('EPSG:4326')"
"""
return "SRS('%s')" % (self.srs_code,)
def __hash__(self):
return hash(self.srs_code)