import logging
import pathlib
from typing import Union, Optional, List, Sequence, overload, BinaryIO
import numpy as np
from . import errors
from .compression import LazBackend
from .header import LasHeader
from .laswriter import LasWriter
from .point import record, dims, ExtraBytesParams, PointFormat
from .point.dims import ScaledArrayView
from .vlrs.vlrlist import VLRList
logger = logging.getLogger(__name__)
[docs]class LasData:
"""Class synchronizing all the moving parts of LAS files.
It connects the point record, header, vlrs together.
To access points dimensions using this class you have two possibilities
.. code:: python
las = pylas.read('some_file.las')
las.classification
# or
las['classification']
"""
def __init__(
self, header: LasHeader, points: Optional[record.PackedPointRecord] = None
) -> None:
if points is None:
points = record.PackedPointRecord.zeros(
header.point_format, header.point_count
)
elif points.point_format != header.point_format:
raise errors.PylasError("Incompatible Point Formats")
self.__dict__["_points"] = points
self.points: record.PackedPointRecord
self.header: LasHeader = header
if header.version.minor >= 4:
self.evlrs: Optional[VLRList] = VLRList()
else:
self.evlrs: Optional[VLRList] = None
@property
def x(self) -> ScaledArrayView:
"""Returns the scaled x positions of the points as doubles"""
return ScaledArrayView(self.X, self.header.x_scale, self.header.x_offset)
@x.setter
def x(self, value) -> None:
if len(value) > len(self.points):
self.points.resize(len(value))
self.x[:] = value
@property
def y(self) -> ScaledArrayView:
"""Returns the scaled y positions of the points as doubles"""
return ScaledArrayView(self.Y, self.header.y_scale, self.header.y_offset)
@y.setter
def y(self, value) -> None:
if len(value) > len(self.points):
self.points.resize(len(value))
self.y[:] = value
@property
def z(self) -> ScaledArrayView:
"""Returns the scaled z positions of the points as doubles"""
return ScaledArrayView(self.Z, self.header.z_scale, self.header.z_offset)
@z.setter
def z(self, value) -> None:
if len(value) > len(self.points):
self.points.resize(len(value))
self.z[:] = value
@property
def point_format(self) -> PointFormat:
"""Shortcut to get the point format"""
return self.points.point_format
@property
def points(self) -> record.PackedPointRecord:
"""Returns the point record"""
return self._points
@points.setter
def points(self, new_points: record.PackedPointRecord) -> None:
if new_points.point_format != self._points.point_format:
raise errors.IncompatibleDataFormat(
"Cannot set points with a different point format, convert first"
)
self._points = new_points
self.update_header()
@property
def vlrs(self) -> VLRList:
return self.header.vlrs
@vlrs.setter
def vlrs(self, vlrs) -> None:
self.header.vlrs = VLRList(vlrs)
@overload
def write(
self,
destination: str,
laz_backend: Optional[Union[LazBackend, Sequence[LazBackend]]] = ...,
) -> None:
...
@overload
def write(
self,
destination: BinaryIO,
do_compress: Optional[bool] = ...,
laz_backend: Optional[Union[LazBackend, Sequence[LazBackend]]] = ...,
) -> None:
...
[docs] def write(self, destination, do_compress=None, laz_backend=None):
"""Writes to a stream or file
.. note::
When destination is a string, it will be interpreted as the path were the file should be written to,
and whether the file will be compressed depends on the extension used (case insensitive):
- .laz -> compressed
- .las -> uncompressed
And the do_compress option will be ignored
Parameters
----------
destination: str or file object
filename or stream to write to
do_compress: bool, optional
Flags to indicate if you want to compress the data
laz_backend: optional, the laz backend to use
By default, pylas detect available backends
"""
if isinstance(destination, (str, pathlib.Path)):
do_compress = pathlib.Path(destination).suffix.lower() == ".laz"
with open(destination, mode="wb+") as out:
self._write_to(out, do_compress=do_compress, laz_backend=laz_backend)
else:
self._write_to(
destination, do_compress=do_compress, laz_backend=laz_backend
)
def _write_to(
self,
out_stream: BinaryIO,
do_compress: Optional[bool] = None,
laz_backend: Optional[Union[LazBackend, Sequence[LazBackend]]] = None,
) -> None:
with LasWriter(
out_stream,
self.header,
do_compress=do_compress,
closefd=False,
laz_backend=laz_backend,
) as writer:
writer.write_points(self.points)
if self.header.version.minor >= 4 and self.evlrs is not None:
writer.write_evlrs(self.evlrs)
[docs] def change_scaling(self, scales=None, offsets=None) -> None:
if scales is None:
scales = self.header.scales
if offsets is None:
offsets = self.header.offsets
record.apply_new_scaling(self, scales, offsets)
self.header.scales = scales
self.header.offsets = offsets
def __getattr__(self, item):
"""Automatically called by Python when the attribute
named 'item' is no found. We use this function to forward the call the
point record. This is the mechanism used to allow the users to access
the points dimensions directly through a LasData.
Parameters
----------
item: str
name of the attribute, should be a dimension name
Returns
-------
The requested dimension if it exists
"""
try:
return self.points[item]
except ValueError:
raise AttributeError(
f"{self.__class__.__name__} object has no attribute '{item}'"
) from None
def __setattr__(self, key, value):
"""This is called on every access to an attribute of the instance.
Again we use this to forward the call the the points record
But this time checking if the key is actually a dimension name
so that an error is raised if the user tries to set a valid
LAS dimension even if it is not present in the field.
eg: user tries to set the red field of a file with point format 0:
an error is raised
"""
if key in self.point_format.dimension_names:
self.points[key] = value
elif key in dims.DIMENSIONS_TO_TYPE:
raise ValueError(
f"Point format {self.point_format} does not support {key} dimension"
)
else:
super().__setattr__(key, value)
def __getitem__(self, item):
return self.points[item]
def __setitem__(self, key, value):
self.points[key] = value
def __repr__(self) -> str:
return "<LasData({}.{}, point fmt: {}, {} points, {} vlrs)>".format(
self.header.version.major,
self.header.version.minor,
self.points.point_format,
len(self.points),
len(self.vlrs),
)