def extent(self, srid=WEB_MERCATOR_SRID):
"""
Returns bbox for layer.
"""
if not self._bbox or self._bbox_srid != srid:
# Get bbox for raster in original coordinates
meta = self.metadata
xmin = meta.uperleftx
ymax = meta.uperlefty
xmax = xmin + meta.width * meta.scalex
ymin = ymax + meta.height * meta.scaley
# Create Polygon box
geom = OGRGeometry(Envelope((xmin, ymin, xmax, ymax)).wkt)
# Set original srs
if meta.srs_wkt:
geom.srs = SpatialReference(meta.srs_wkt)
else:
geom.srid = meta.srid
# Transform to requested srid
geom.transform(srid)
# Calculate value range for bbox
coords = geom.coords[0]
xvals = [x[0] for x in coords]
yvals = [x[1] for x in coords]
# Set bbox
self._bbox = (min(xvals), min(yvals), max(xvals), max(yvals))
self._bbox_srid = srid
return self._bbox
def extent(self, srid=WEB_MERCATOR_SRID):
"""
Returns bbox for layer.
"""
if not self._bbox or self._bbox_srid != srid:
# Get bbox for raster in original coordinates
meta = self.metadata
xmin = meta.uperleftx
ymax = meta.uperlefty
xmax = xmin + meta.width * meta.scalex
ymin = ymax + meta.height * meta.scaley
# Create Polygon box
geom = OGRGeometry(Envelope((xmin, ymin, xmax, ymax)).wkt)
# Set original srs
if meta.srs_wkt:
geom.srs = SpatialReference(meta.srs_wkt)
else:
geom.srid = meta.srid
# Transform to requested srid
geom.transform(srid)
# Calculate value range for bbox
coords = geom.coords[0]
xvals = [x[0] for x in coords]
yvals = [x[1] for x in coords]
# Set bbox
self._bbox = (min(xvals), min(yvals), max(xvals), max(yvals))
self._bbox_srid = srid
return self._bbox
def test_srs(self):
"Testing OGR Geometries with Spatial Reference objects."
for mp in self.geometries.multipolygons:
# Creating a geometry w/spatial reference
sr = SpatialReference('WGS84')
mpoly = OGRGeometry(mp.wkt, sr)
self.assertEqual(sr.wkt, mpoly.srs.wkt)
# Ensuring that SRS is propagated to clones.
klone = mpoly.clone()
self.assertEqual(sr.wkt, klone.srs.wkt)
# Ensuring all children geometries (polygons and their rings) all
# return the assigned spatial reference as well.
for poly in mpoly:
self.assertEqual(sr.wkt, poly.srs.wkt)
for ring in poly:
self.assertEqual(sr.wkt, ring.srs.wkt)
# Ensuring SRS propagate in topological ops.
a = OGRGeometry(self.geometries.topology_geoms[0].wkt_a, sr)
b = OGRGeometry(self.geometries.topology_geoms[0].wkt_b, sr)
diff = a.difference(b)
union = a.union(b)
self.assertEqual(sr.wkt, diff.srs.wkt)
self.assertEqual(sr.srid, union.srs.srid)
# Instantiating w/an integer SRID
mpoly = OGRGeometry(mp.wkt, 4326)
self.assertEqual(4326, mpoly.srid)
mpoly.srs = SpatialReference(4269)
self.assertEqual(4269, mpoly.srid)
self.assertEqual('NAD83', mpoly.srs.name)
# Incrementing through the multipolygon after the spatial reference
# has been re-assigned.
for poly in mpoly:
self.assertEqual(mpoly.srs.wkt, poly.srs.wkt)
poly.srs = 32140
for ring in poly:
# Changing each ring in the polygon
self.assertEqual(32140, ring.srs.srid)
self.assertEqual('NAD83 / Texas South Central',
ring.srs.name)
ring.srs = str(SpatialReference(4326)) # back to WGS84
self.assertEqual(4326, ring.srs.srid)
# Using the `srid` property.
ring.srid = 4322
self.assertEqual('WGS 72', ring.srs.name)
self.assertEqual(4322, ring.srid)
# srs/srid may be assigned their own values, even when srs is None.
mpoly = OGRGeometry(mp.wkt, srs=None)
mpoly.srs = mpoly.srs
mpoly.srid = mpoly.srid
def test_srs(self):
"Testing OGR Geometries with Spatial Reference objects."
for mp in self.geometries.multipolygons:
# Creating a geometry w/spatial reference
sr = SpatialReference("WGS84")
mpoly = OGRGeometry(mp.wkt, sr)
self.assertEqual(sr.wkt, mpoly.srs.wkt)
# Ensuring that SRS is propagated to clones.
klone = mpoly.clone()
self.assertEqual(sr.wkt, klone.srs.wkt)
# Ensuring all children geometries (polygons and their rings) all
# return the assigned spatial reference as well.
for poly in mpoly:
self.assertEqual(sr.wkt, poly.srs.wkt)
for ring in poly:
self.assertEqual(sr.wkt, ring.srs.wkt)
# Ensuring SRS propagate in topological ops.
a = OGRGeometry(self.geometries.topology_geoms[0].wkt_a, sr)
b = OGRGeometry(self.geometries.topology_geoms[0].wkt_b, sr)
diff = a.difference(b)
union = a.union(b)
self.assertEqual(sr.wkt, diff.srs.wkt)
self.assertEqual(sr.srid, union.srs.srid)
# Instantiating w/an integer SRID
mpoly = OGRGeometry(mp.wkt, 4326)
self.assertEqual(4326, mpoly.srid)
mpoly.srs = SpatialReference(4269)
self.assertEqual(4269, mpoly.srid)
self.assertEqual("NAD83", mpoly.srs.name)
# Incrementing through the multipolygon after the spatial reference
# has been re-assigned.
for poly in mpoly:
self.assertEqual(mpoly.srs.wkt, poly.srs.wkt)
poly.srs = 32140
for ring in poly:
# Changing each ring in the polygon
self.assertEqual(32140, ring.srs.srid)
self.assertEqual("NAD83 / Texas South Central", ring.srs.name)
ring.srs = str(SpatialReference(4326)) # back to WGS84
self.assertEqual(4326, ring.srs.srid)
# Using the `srid` property.
ring.srid = 4322
self.assertEqual("WGS 72", ring.srs.name)
self.assertEqual(4322, ring.srid)
# srs/srid may be assigned their own values, even when srs is None.
mpoly = OGRGeometry(mp.wkt, srs=None)
mpoly.srs = mpoly.srs
mpoly.srid = mpoly.srid
def pixel_value_from_point(raster, point, band=0):
"""
Returns the pixel value for the coordinate of the input point from selected
band.
The input can be a point or tuple, if its a tuple it is assumed to be
coordinates in the reference system of the raster.
"""
if isinstance(point, (tuple, list)):
point = OGRGeometry('POINT({0} {1})'.format(*point))
point.srid = raster.srid
elif not point.srs or not raster.srs:
raise ValueError(
'Both the point and the raster are required to have a reference system specified.'
)
elif point.srs != raster.srs:
# Ensure the projection of the point is the same as of the raster.
point.transform(raster.srid)
# Return if point and raster do not touch.
bbox = OGRGeometry.from_bbox(raster.extent)
bbox.srs = raster.srs
if not point.intersects(bbox):
return
# Compute position of point relative to raster origin.
offset = (abs(raster.origin.x - point.coords[0]),
abs(raster.origin.y - point.coords[1]))
# Compute pixel index value based on offset.
offset_index = [
int(offset[0] / abs(raster.scale.x)),
int(offset[1] / abs(raster.scale.y))
]
# If the point is exactly on the boundary, the offset_index is rounded to
# a pixel index over the edge of the pixel. The index needs to be reduced
# by one pixel for those cases.
if offset_index[0] == raster.width:
offset_index[0] -= 1
if offset_index[1] == raster.height:
offset_index[1] -= 1
return raster.bands[band].data(offset=offset_index, size=(1, 1))[0, 0]
def pixel_value_from_point(raster, point, band=0):
"""
Returns the pixel value for the coordinate of the input point from selected
band.
The input can be a point or tuple, if its a tuple it is assumed to be
coordinates in the reference system of the raster.
"""
if isinstance(point, (tuple, list)):
point = OGRGeometry('POINT({0} {1})'.format(*point))
point.srid = raster.srid
elif not point.srs or not raster.srs:
raise ValueError('Both the point and the raster are required to have a reference system specified.')
elif point.srs != raster.srs:
# Ensure the projection of the point is the same as of the raster.
point.transform(raster.srid)
# Return if point and raster do not touch.
bbox = OGRGeometry.from_bbox(raster.extent)
bbox.srs = raster.srs
if not point.intersects(bbox):
return
# Compute position of point relative to raster origin.
offset = (abs(raster.origin.x - point.coords[0]), abs(raster.origin.y - point.coords[1]))
# Compute pixel index value based on offset.
offset_index = [int(offset[0] / abs(raster.scale.x)), int(offset[1] / abs(raster.scale.y))]
# If the point is exactly on the boundary, the offset_index is rounded to
# a pixel index over the edge of the pixel. The index needs to be reduced
# by one pixel for those cases.
if offset_index[0] == raster.width:
offset_index[0] -= 1
if offset_index[1] == raster.height:
offset_index[1] -= 1
return raster.bands[band].data(offset=offset_index, size=(1, 1))[0, 0]
