def raster(self):
imfield = self.image
# Check _file attr to avoid opening a file handle.
if isinstance(getattr(imfield, '_file', None), MemFileIO):
path = imfield.file.name
else:
path = self.image.path
return greenwich.Raster(path)
def raster(self):
imfield = self.image
# Check _file attr to avoid opening a file handle.
fileobj = getattr(imfield, '_file', None)
if isinstance(fileobj, MemFileIO):
path = imfield.file.name
elif fileobj and fileobj.name.startswith(tempfile.gettempdir()):
path = fileobj.name
else:
path = self.image.path
return greenwich.Raster(path)
def array(self, geom=None, stat=None):
with greenwich.Raster(self.image.path) as r:
if geom:
if geom.num_coords > 1:
with r.clip(geom) as clipped:
arr = clipped.masked_array()
else:
coord_px = r.affine.transform((geom.coords,)).pop()
arr = r.ReadAsArray(*(coord_px + (1, 1)))
else:
arr = r.masked_array()
if arr is not None:
if stat:
arr = getattr(np.ma, stat)(arr)
if arr.size == 1:
arr = arr.item()
return arr
raise ValueError('Failure reading array values')
def convert(self, format=None, geom=None):
imgpath = self.image.path
# Handle format as .tif, tif, or tif.zip
ext = format or os.path.splitext(imgpath)[-1][1:]
ext = os.path.splitext(ext)[0]
driver = greenwich.driver_for_path('base.%s' % ext)
# No conversion is needed if the original format without clipping
# is requested.
if not geom and imgpath.endswith(ext):
return
memio = MemFileIO()
if geom:
with greenwich.Raster(imgpath) as r:
with r.clip(geom) as clipped:
clipped.save(memio, driver)
else:
driver.copy(imgpath, memio.name)
self.image.file = memio
def clean_fields(self, *args, **kwargs):
# Override this instead of save() so that fields are populated on
# save() *or* manager methods like RasterStore.objects.create().
if not self.image.storage.exists(self.image):
self.image.save(self.image.name, self.image, save=False)
with greenwich.Raster(self.image.path) as r:
band = r[-1]
bmin, bmax = band.GetMinimum(), band.GetMaximum()
if bmin is None or bmax is None:
bmin, bmax = band.ComputeRasterMinMax()
self.geom = buffer(r.envelope.polygon.ExportToWkb())
if r.sref.srid:
self.geom.srid = r.sref.srid
self.xpixsize, self.ypixsize = r.affine.scale
self.width, self.height = r.size
self.minval = bmin
self.maxval = bmax
self.nodata = r.nodata
self.srs = r.sref.wkt
if self.event is None:
self.event = datetime.date.today()
super(AbstractRasterStore, self).clean_fields(*args, **kwargs)
def warp(self, format=None, srid=None, geom=None):
"""Returns a new RasterQuerySet with possibly warped/converted rasters.
Keyword args:
format -- raster file extension format as str
geom -- geometry for masking or spatial subsetting
srid -- spatial reference identifier as int for warping to
"""
clone = self._clone()
for obj in clone:
obj.convert(format, geom)
if srid:
f = obj.image.file
if isinstance(f, MemFileIO):
r = greenwich.Raster(f.name)
else:
r = obj.raster()
memio = MemFileIO(delete=False)
dswarp = r.warp(srid, memio)
obj.image.file = memio
dswarp.close()
r.close()
return clone
def convert(self, format=None, geom=None):
imgpath = self.image.path
# Handle format as .tif, tif, or tif.zip
ext = format or os.path.splitext(imgpath)[-1][1:]
ext = os.path.splitext(ext)[0]
# No conversion is needed if the original format without clipping
# is requested.
if not geom and imgpath.endswith(ext):
return
driver = greenwich.driver_for_path(ext, _imgdrivers)
# Allow overriding of default driver settings.
settings = self.driver_settings.get(ext)
if settings:
driver.settings = settings
memio = MemFileIO()
if geom:
with greenwich.Raster(imgpath) as r, r.clip(geom) as clipped:
clipped.save(memio, driver)
else:
driver.copy(imgpath, memio.name)
self.image.name = os.extsep.join(
(os.path.splitext(os.path.basename(imgpath))[0], ext))
self.image.file = memio
def quantiles(self, k=5):
"""Returns an ndarray of quantile breaks."""
with greenwich.Raster(self.image.path) as rast:
arr = rast.masked_array()
q = list(np.linspace(0, 100, k))
return np.percentile(arr.compressed(), q)
def raster(self):
return greenwich.Raster(self.image.path)
