mirror of
https://github.com/django/django.git
synced 2025-09-26 12:09:19 +00:00
Added write support for GDALRaster
- Instantiation of GDALRaster instances from dict or json data. - Retrieve and write pixel values in GDALBand objects. - Support for the GDALFlushCache in gdal C prototypes - Added private flush method to GDALRaster to make sure all data is written to files when file-based rasters are changed. - Replaced ``ptr`` with ``_ptr`` for internal ptr variable Refs #23804. Thanks Claude Paroz and Tim Graham for the reviews.
This commit is contained in:
Daniel Wiesmann
Claude Paroz
parent
8758a63ddb
commit
f269c1d6f6
11 changed files with 600 additions and 57 deletions
|
|
@ -1,3 +1,4 @@
|
|||
import json
|
||||
import os
|
||||
from ctypes import addressof, byref, c_double
|
||||
|
||||
|
|
@ -7,6 +8,7 @@ from django.contrib.gis.gdal.error import GDALException
|
|||
from django.contrib.gis.gdal.prototypes import raster as capi
|
||||
from django.contrib.gis.gdal.raster.band import GDALBand
|
||||
from django.contrib.gis.gdal.srs import SpatialReference, SRSException
|
||||
from django.contrib.gis.geometry.regex import json_regex
|
||||
from django.utils import six
|
||||
from django.utils.encoding import (
|
||||
force_bytes, force_text, python_2_unicode_compatible,
|
||||
|
|
@ -33,10 +35,22 @@ class TransformPoint(list):
|
|||
def x(self):
|
||||
return self[0]
|
||||
|
||||
@x.setter
|
||||
def x(self, value):
|
||||
gtf = self._raster.geotransform
|
||||
gtf[self.indices[self._prop][0]] = value
|
||||
self._raster.geotransform = gtf
|
||||
|
||||
@property
|
||||
def y(self):
|
||||
return self[1]
|
||||
|
||||
@y.setter
|
||||
def y(self, value):
|
||||
gtf = self._raster.geotransform
|
||||
gtf[self.indices[self._prop][1]] = value
|
||||
self._raster.geotransform = gtf
|
||||
|
||||
|
||||
@python_2_unicode_compatible
|
||||
class GDALRaster(GDALBase):
|
||||
|
|
@ -47,17 +61,64 @@ class GDALRaster(GDALBase):
|
|||
self._write = 1 if write else 0
|
||||
Driver.ensure_registered()
|
||||
|
||||
# Preprocess json inputs. This converts json strings to dictionaries,
|
||||
# which are parsed below the same way as direct dictionary inputs.
|
||||
if isinstance(ds_input, six.string_types) and json_regex.match(ds_input):
|
||||
ds_input = json.loads(ds_input)
|
||||
|
||||
# If input is a valid file path, try setting file as source.
|
||||
if isinstance(ds_input, six.string_types):
|
||||
if os.path.exists(ds_input):
|
||||
try:
|
||||
# GDALOpen will auto-detect the data source type.
|
||||
self.ptr = capi.open_ds(force_bytes(ds_input), self._write)
|
||||
except GDALException as err:
|
||||
raise GDALException('Could not open the datasource at "{}" ({}).'.format(
|
||||
ds_input, err))
|
||||
else:
|
||||
if not os.path.exists(ds_input):
|
||||
raise GDALException('Unable to read raster source input "{}"'.format(ds_input))
|
||||
try:
|
||||
# GDALOpen will auto-detect the data source type.
|
||||
self._ptr = capi.open_ds(force_bytes(ds_input), self._write)
|
||||
except GDALException as err:
|
||||
raise GDALException('Could not open the datasource at "{}" ({}).'.format(ds_input, err))
|
||||
elif isinstance(ds_input, dict):
|
||||
# A new raster needs to be created in write mode
|
||||
self._write = 1
|
||||
|
||||
# Create driver (in memory by default)
|
||||
driver = Driver(ds_input.get('driver', 'MEM'))
|
||||
|
||||
# For out of memory drivers, check filename argument
|
||||
if driver.name != 'MEM' and 'name' not in ds_input:
|
||||
raise GDALException('Specify name for creation of raster with driver "{}".'.format(driver.name))
|
||||
|
||||
# Check if width and height where specified
|
||||
if 'width' not in ds_input or 'height' not in ds_input:
|
||||
raise GDALException('Specify width and height attributes for JSON or dict input.')
|
||||
|
||||
# Create GDAL Raster
|
||||
self._ptr = capi.create_ds(
|
||||
driver._ptr,
|
||||
force_bytes(ds_input.get('name', '')),
|
||||
ds_input['width'],
|
||||
ds_input['height'],
|
||||
ds_input.get('nr_of_bands', len(ds_input.get('bands', []))),
|
||||
ds_input.get('datatype', 6),
|
||||
None
|
||||
)
|
||||
|
||||
# Set band data if provided
|
||||
for i, band_input in enumerate(ds_input.get('bands', [])):
|
||||
self.bands[i].data(band_input['data'])
|
||||
if 'nodata_value' in band_input:
|
||||
self.bands[i].nodata_value = band_input['nodata_value']
|
||||
|
||||
# Set SRID, default to 0 (this assures SRS is always instanciated)
|
||||
self.srs = ds_input.get('srid', 0)
|
||||
|
||||
# Set additional properties if provided
|
||||
if 'origin' in ds_input:
|
||||
self.origin.x, self.origin.y = ds_input['origin']
|
||||
|
||||
if 'scale' in ds_input:
|
||||
self.scale.x, self.scale.y = ds_input['scale']
|
||||
|
||||
if 'skew' in ds_input:
|
||||
self.skew.x, self.skew.y = ds_input['skew']
|
||||
else:
|
||||
raise GDALException('Invalid data source input type: "{}".'.format(type(ds_input)))
|
||||
|
||||
|
|
@ -72,15 +133,34 @@ class GDALRaster(GDALBase):
|
|||
"""
|
||||
Short-hand representation because WKB may be very large.
|
||||
"""
|
||||
return '<Raster object at %s>' % hex(addressof(self.ptr))
|
||||
return '<Raster object at %s>' % hex(addressof(self._ptr))
|
||||
|
||||
def _flush(self):
|
||||
"""
|
||||
Flush all data from memory into the source file if it exists.
|
||||
The data that needs flushing are geotransforms, coordinate systems,
|
||||
nodata_values and pixel values. This function will be called
|
||||
automatically wherever it is needed.
|
||||
"""
|
||||
# Raise an Exception if the value is being changed in read mode.
|
||||
if not self._write:
|
||||
raise GDALException('Raster needs to be opened in write mode to change values.')
|
||||
capi.flush_ds(self._ptr)
|
||||
|
||||
@property
|
||||
def name(self):
|
||||
return force_text(capi.get_ds_description(self.ptr))
|
||||
"""
|
||||
Returns the name of this raster. Corresponds to filename
|
||||
for file-based rasters.
|
||||
"""
|
||||
return force_text(capi.get_ds_description(self._ptr))
|
||||
|
||||
@cached_property
|
||||
def driver(self):
|
||||
ds_driver = capi.get_ds_driver(self.ptr)
|
||||
"""
|
||||
Returns the GDAL Driver used for this raster.
|
||||
"""
|
||||
ds_driver = capi.get_ds_driver(self._ptr)
|
||||
return Driver(ds_driver)
|
||||
|
||||
@property
|
||||
|
|
@ -88,48 +168,85 @@ class GDALRaster(GDALBase):
|
|||
"""
|
||||
Width (X axis) in pixels.
|
||||
"""
|
||||
return capi.get_ds_xsize(self.ptr)
|
||||
return capi.get_ds_xsize(self._ptr)
|
||||
|
||||
@property
|
||||
def height(self):
|
||||
"""
|
||||
Height (Y axis) in pixels.
|
||||
"""
|
||||
return capi.get_ds_ysize(self.ptr)
|
||||
return capi.get_ds_ysize(self._ptr)
|
||||
|
||||
@property
|
||||
def srs(self):
|
||||
"""
|
||||
Returns the Spatial Reference used in this GDALRaster.
|
||||
Returns the SpatialReference used in this GDALRaster.
|
||||
"""
|
||||
try:
|
||||
wkt = capi.get_ds_projection_ref(self.ptr)
|
||||
wkt = capi.get_ds_projection_ref(self._ptr)
|
||||
if not wkt:
|
||||
return None
|
||||
return SpatialReference(wkt, srs_type='wkt')
|
||||
except SRSException:
|
||||
return None
|
||||
|
||||
@cached_property
|
||||
@srs.setter
|
||||
def srs(self, value):
|
||||
"""
|
||||
Sets the spatial reference used in this GDALRaster. The input can be
|
||||
a SpatialReference or any parameter accepted by the SpatialReference
|
||||
constructor.
|
||||
"""
|
||||
if isinstance(value, SpatialReference):
|
||||
srs = value
|
||||
elif isinstance(value, six.integer_types + six.string_types):
|
||||
srs = SpatialReference(value)
|
||||
else:
|
||||
raise ValueError('Could not create a SpatialReference from input.')
|
||||
capi.set_ds_projection_ref(self._ptr, srs.wkt.encode())
|
||||
self._flush()
|
||||
|
||||
@property
|
||||
def geotransform(self):
|
||||
"""
|
||||
Returns the geotransform of the data source.
|
||||
Returns the default geotransform if it does not exist or has not been
|
||||
set previously. The default is (0.0, 1.0, 0.0, 0.0, 0.0, -1.0).
|
||||
set previously. The default is [0.0, 1.0, 0.0, 0.0, 0.0, -1.0].
|
||||
"""
|
||||
# Create empty ctypes double array for data
|
||||
gtf = (c_double * 6)()
|
||||
capi.get_ds_geotransform(self.ptr, byref(gtf))
|
||||
return tuple(gtf)
|
||||
capi.get_ds_geotransform(self._ptr, byref(gtf))
|
||||
return list(gtf)
|
||||
|
||||
@geotransform.setter
|
||||
def geotransform(self, values):
|
||||
"Sets the geotransform for the data source."
|
||||
if sum([isinstance(x, (int, float)) for x in values]) != 6:
|
||||
raise ValueError('Geotransform must consist of 6 numeric values.')
|
||||
# Create ctypes double array with input and write data
|
||||
values = (c_double * 6)(*values)
|
||||
capi.set_ds_geotransform(self._ptr, byref(values))
|
||||
self._flush()
|
||||
|
||||
@property
|
||||
def origin(self):
|
||||
"""
|
||||
Coordinates of the raster origin.
|
||||
"""
|
||||
return TransformPoint(self, 'origin')
|
||||
|
||||
@property
|
||||
def scale(self):
|
||||
"""
|
||||
Pixel scale in units of the raster projection.
|
||||
"""
|
||||
return TransformPoint(self, 'scale')
|
||||
|
||||
@property
|
||||
def skew(self):
|
||||
"""
|
||||
Skew of pixels (rotation parameters).
|
||||
"""
|
||||
return TransformPoint(self, 'skew')
|
||||
|
||||
@property
|
||||
|
|
@ -150,7 +267,10 @@ class GDALRaster(GDALBase):
|
|||
|
||||
@cached_property
|
||||
def bands(self):
|
||||
"""
|
||||
Returns the bands of this raster as a list of GDALBand instances.
|
||||
"""
|
||||
bands = []
|
||||
for idx in range(1, capi.get_ds_raster_count(self.ptr) + 1):
|
||||
for idx in range(1, capi.get_ds_raster_count(self._ptr) + 1):
|
||||
bands.append(GDALBand(self, idx))
|
||||
return bands
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue