"""rasterio.vrt: a module concerned with GDAL VRTs""" import xml.etree.ElementTree as ET import rasterio from rasterio._warp import WarpedVRTReaderBase from rasterio.dtypes import _gdal_typename from rasterio.enums import MaskFlags from rasterio._path import _parse_path from rasterio.transform import TransformMethodsMixin from rasterio.windows import WindowMethodsMixin class WarpedVRT(WarpedVRTReaderBase, WindowMethodsMixin, TransformMethodsMixin): """A virtual warped dataset. Abstracts the details of raster warping and allows access to data that is reprojected when read. This class is backed by an in-memory GDAL VRTWarpedDataset VRT file. Parameters ---------- src_dataset : dataset object The warp source. src_crs : CRS or str, optional Overrides the coordinate reference system of `src_dataset`. src_transfrom : Affine, optional Overrides the transform of `src_dataset`. src_nodata : float, optional Overrides the nodata value of `src_dataset`, which is the default. crs : CRS or str, optional The coordinate reference system at the end of the warp operation. Default: the crs of `src_dataset`. dst_crs was a deprecated alias for this parameter. transform : Affine, optional The transform for the virtual dataset. Default: will be computed from the attributes of `src_dataset`. dst_transform was a deprecated alias for this parameter. height, width: int, optional The dimensions of the virtual dataset. Defaults: will be computed from the attributes of `src_dataset`. dst_height and dst_width were deprecated alias for these parameters. nodata : float, optional Nodata value for the virtual dataset. Default: the nodata value of `src_dataset` or 0.0. dst_nodata was a deprecated alias for this parameter. resampling : Resampling, optional Warp resampling algorithm. Default: `Resampling.nearest`. tolerance : float, optional The maximum error tolerance in input pixels when approximating the warp transformation. Default: 0.125, or one-eigth of a pixel. src_alpha : int, optional Index of a source band to use as an alpha band for warping. dst_alpha : int, optional Index of a destination band to use as an alpha band for warping. add_alpha : bool, optional Whether to add an alpha masking band to the virtual dataset. Default: False. This option will cause deletion of the VRT nodata value. init_dest_nodata : bool, optional Whether or not to initialize output to `nodata`. Default: True. warp_mem_limit : int, optional The warp operation's memory limit in MB. The default (0) means 64 MB with GDAL 2.2. dtype : str, optional The working data type for warp operation and output. warp_extras : dict GDAL extra warp options. See https://gdal.org/doxygen/structGDALWarpOptions.html. Attributes ---------- src_dataset : dataset The dataset object to be virtually warped. resampling : int One of the values from rasterio.enums.Resampling. The default is `Resampling.nearest`. tolerance : float The maximum error tolerance in input pixels when approximating the warp transformation. The default is 0.125. src_nodata: int or float, optional The source nodata value. Pixels with this value will not be used for interpolation. If not set, it will be default to the nodata value of the source image, if available. dst_nodata: int or float, optional The nodata value used to initialize the destination; it will remain in all areas not covered by the reprojected source. Defaults to the value of src_nodata, or 0 (gdal default). working_dtype : str, optional The working data type for warp operation and output. warp_extras : dict GDAL extra warp options. See https://gdal.org/doxygen/structGDALWarpOptions.html. Examples -------- >>> with rasterio.open('tests/data/RGB.byte.tif') as src: ... with WarpedVRT(src, crs='EPSG:3857') as vrt: ... data = vrt.read() """ def __repr__(self): return "<{} WarpedVRT name='{}' mode='{}'>".format( self.closed and 'closed' or 'open', self.name, self.mode) def __enter__(self): self.start() return self def __exit__(self, *args, **kwargs): if not self._closed: self.close() def __del__(self): if not self._closed: self.close() def _boundless_vrt_doc( src_dataset, nodata=None, background=None, hidenodata=False, width=None, height=None, transform=None, masked=False): """Make a VRT XML document. Parameters ---------- src_dataset : Dataset The dataset to wrap. background : int or float, optional The background fill value for the boundless VRT. masked : bool If True, the src_dataset is replaced by its valid data mask. Returns ------- str An XML text string. """ nodata = nodata or src_dataset.nodata width = width or src_dataset.width height = height or src_dataset.height transform = transform or src_dataset.transform vrtdataset = ET.Element('VRTDataset') vrtdataset.attrib['rasterYSize'] = str(height) vrtdataset.attrib['rasterXSize'] = str(width) srs = ET.SubElement(vrtdataset, 'SRS') srs.text = src_dataset.crs.wkt if src_dataset.crs else "" geotransform = ET.SubElement(vrtdataset, 'GeoTransform') geotransform.text = ','.join([str(v) for v in transform.to_gdal()]) for bidx, ci, block_shape, dtype in zip(src_dataset.indexes, src_dataset.colorinterp, src_dataset.block_shapes, src_dataset.dtypes): vrtrasterband = ET.SubElement(vrtdataset, 'VRTRasterBand') vrtrasterband.attrib['dataType'] = _gdal_typename(dtype) vrtrasterband.attrib['band'] = str(bidx) if background is not None or nodata is not None: nodatavalue = ET.SubElement(vrtrasterband, 'NoDataValue') nodatavalue.text = str(background or nodata) if hidenodata: hidenodatavalue = ET.SubElement(vrtrasterband, 'HideNoDataValue') hidenodatavalue.text = "1" colorinterp = ET.SubElement(vrtrasterband, 'ColorInterp') colorinterp.text = ci.name.capitalize() complexsource = ET.SubElement(vrtrasterband, 'ComplexSource') sourcefilename = ET.SubElement(complexsource, 'SourceFilename') sourcefilename.attrib['relativeToVRT'] = "0" sourcefilename.attrib["shared"] = "0" sourcefilename.text = _parse_path(src_dataset.name).as_vsi() sourceband = ET.SubElement(complexsource, 'SourceBand') sourceband.text = str(bidx) sourceproperties = ET.SubElement(complexsource, 'SourceProperties') sourceproperties.attrib['RasterXSize'] = str(width) sourceproperties.attrib['RasterYSize'] = str(height) sourceproperties.attrib['dataType'] = _gdal_typename(dtype) sourceproperties.attrib['BlockYSize'] = str(block_shape[0]) sourceproperties.attrib['BlockXSize'] = str(block_shape[1]) srcrect = ET.SubElement(complexsource, 'SrcRect') srcrect.attrib['xOff'] = '0' srcrect.attrib['yOff'] = '0' srcrect.attrib['xSize'] = str(src_dataset.width) srcrect.attrib['ySize'] = str(src_dataset.height) dstrect = ET.SubElement(complexsource, 'DstRect') dstrect.attrib['xOff'] = str((src_dataset.transform.xoff - transform.xoff) / transform.a) dstrect.attrib['yOff'] = str((src_dataset.transform.yoff - transform.yoff) / transform.e) dstrect.attrib['xSize'] = str(src_dataset.width * src_dataset.transform.a / transform.a) dstrect.attrib['ySize'] = str(src_dataset.height * src_dataset.transform.e / transform.e) if src_dataset.nodata is not None: nodata_elem = ET.SubElement(complexsource, 'NODATA') nodata_elem.text = str(src_dataset.nodata) if src_dataset.options is not None: openoptions = ET.SubElement(complexsource, 'OpenOptions') for ookey, oovalue in src_dataset.options.items(): ooi = ET.SubElement(openoptions, 'OOI') ooi.attrib['key'] = str(ookey) ooi.text = str(oovalue) # Effectively replaces all values of the source dataset with # 255. Due to GDAL optimizations, the source dataset will not # be read, so we get a performance improvement. if masked: scaleratio = ET.SubElement(complexsource, 'ScaleRatio') scaleratio.text = '0' scaleoffset = ET.SubElement(complexsource, 'ScaleOffset') scaleoffset.text = '255' if all(MaskFlags.per_dataset in flags for flags in src_dataset.mask_flag_enums): maskband = ET.SubElement(vrtdataset, 'MaskBand') vrtrasterband = ET.SubElement(maskband, 'VRTRasterBand') vrtrasterband.attrib['dataType'] = 'Byte' simplesource = ET.SubElement(vrtrasterband, 'SimpleSource') sourcefilename = ET.SubElement(simplesource, 'SourceFilename') sourcefilename.attrib['relativeToVRT'] = "0" sourcefilename.attrib["shared"] = "0" sourcefilename.text = _parse_path(src_dataset.name).as_vsi() sourceband = ET.SubElement(simplesource, 'SourceBand') sourceband.text = 'mask,1' sourceproperties = ET.SubElement(simplesource, 'SourceProperties') sourceproperties.attrib['RasterXSize'] = str(width) sourceproperties.attrib['RasterYSize'] = str(height) sourceproperties.attrib['dataType'] = 'Byte' sourceproperties.attrib['BlockYSize'] = str(block_shape[0]) sourceproperties.attrib['BlockXSize'] = str(block_shape[1]) srcrect = ET.SubElement(simplesource, 'SrcRect') srcrect.attrib['xOff'] = '0' srcrect.attrib['yOff'] = '0' srcrect.attrib['xSize'] = str(src_dataset.width) srcrect.attrib['ySize'] = str(src_dataset.height) dstrect = ET.SubElement(simplesource, 'DstRect') dstrect.attrib['xOff'] = str((src_dataset.transform.xoff - transform.xoff) / transform.a) dstrect.attrib['yOff'] = str((src_dataset.transform.yoff - transform.yoff) / transform.e) dstrect.attrib['xSize'] = str(src_dataset.width) dstrect.attrib['ySize'] = str(src_dataset.height) return ET.tostring(vrtdataset).decode('ascii')