# BEGIN OF LICENSE NOTE
# This file is part of Pyoints.
# Copyright (c) 2018, Sebastian Lamprecht, Trier University,
# lamprecht@uni-trier.de
#
# Pyoints is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Pyoints is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Pyoints. If not, see <https://www.gnu.org/licenses/>.
# END OF LICENSE NOTE
"""Helper functions for data type conersion.
"""
import numpy as np
from osgeo import gdal
# Laspy
########
"""
# see https://pythonhosted.org/laspy/tut_part_3.html
0 Raw Extra Bytes Value of "options"
1 unsigned char 1 byte
2 Char 1 byte
3 unsigned short 2 bytes
4 Short 2 bytes
5 unsigned long 4 bytes
6 Long 4 bytes
7 unsigned long long 8 bytes
8 long long 8 bytes
9 Float 4 bytes
10 Double 8 bytes
11 unsigned char[2] 2 byte
12 char[2] 2 byte
13 unsigned short[2] 4 bytes
14 short[2] 4 bytes
15 unsigned long[2] 8 bytes
16 long[2] 8 bytes
17 unsigned long long[2] 16 bytes
18 long long[2] 16 bytes
19 float[2] 8 bytes
20 double[2] 16 bytes
21 unsigned char[3] 3 byte
22 char[3] 3 byte
23 unsigned short[3] 6 bytes
24 short[3] 6 bytes
25 unsigned long[3] 12 bytes
26 long[3] 12 bytes
27 unsigned long long[3] 24 bytes
28 long long[3] 24 bytes
29 float[3] 12 bytes
30 double[3] 24 bytes
"""
LASPY_TYPE_MAP = [
(1, ['|u1']),
(2, ['|S1']),
(3, ['<u2']),
(4, ['<i2']),
(5, ['<u4']),
(6, ['<i4', '<i8']),
(7, ['<u8']),
(8, []), # error occurs
(9, ['<f4']),
(10, ['<f8']),
]
LASPY_TO_NUMPY_TYPE = {}
for dim in range(1, 4):
for key, t in LASPY_TYPE_MAP:
if len(t) > 0:
type_id = key + len(LASPY_TYPE_MAP) * (dim - 1)
LASPY_TO_NUMPY_TYPE[type_id] = (t[0], dim)
NUMPY_TO_LASPY_TYPE = {}
for dim in range(1, 4):
NUMPY_TO_LASPY_TYPE[dim] = {}
for t, p in LASPY_TYPE_MAP:
type_id = t + len(LASPY_TYPE_MAP) * (dim - 1)
for key in p:
NUMPY_TO_LASPY_TYPE[dim][key] = type_id
[docs]def numpy_to_laspy_dtype(dtype):
"""Converts a numpy data type to a laspy data type.
Parameters
----------
dtype : np.dtype
Numpy data type to convert.
Returns
-------
int
Laspy data type id.
Examples
--------
>>> dtype = np.dtype(np.int32)
>>> print(numpy_to_laspy_dtype(dtype))
6
"""
dtype = np.dtype(dtype)
if dtype.subdtype is None:
dt = dtype
type_name = dt.str
type_dim = dt.shape[0] if len(dt.shape) > 0 else 1
else:
dt = dtype.subdtype
type_name = dt[0].str
type_dim = dt[1][0] if len(dt[1]) > 0 else 1
if type_dim not in NUMPY_TO_LASPY_TYPE.keys():
return None
if type_name not in NUMPY_TO_LASPY_TYPE[type_dim].keys():
return None
return NUMPY_TO_LASPY_TYPE[type_dim][type_name]
# GDAL
#######
NUMPY_TO_GDAL_TYPE = {
'|u1': gdal.GDT_Byte,
'|i1': gdal.GDT_Byte,
'<u2': gdal.GDT_UInt16,
'<i2': gdal.GDT_Int16,
'<u4': gdal.GDT_UInt32,
'<i4': gdal.GDT_Int32,
'<u8': gdal.GDT_Float32,
'<i8': gdal.GDT_Float32,
'<f2': gdal.GDT_Float32,
'<f4': gdal.GDT_Float32,
'<f8': gdal.GDT_Float64,
'<c8': gdal.GDT_CFloat32,
'<c16': gdal.GDT_CFloat64,
}
[docs]def numpy_to_gdal_dtype(dtype):
"""Converts a numpy data type to a gdal data type.
Parameters
----------
dtype : np.dtype
Numpy data type to convert.
Returns
-------
int
Gdal data type id.
Examples
--------
>>> dtype = np.dtype(np.int32)
>>> print(numpy_to_gdal_dtype(dtype))
5
"""
dtype = np.dtype(dtype)
key = dtype.str
if key not in NUMPY_TO_GDAL_TYPE:
raise ValueError("data type '%s' not found" % key)
return NUMPY_TO_GDAL_TYPE[key]
