Coverage for py_tools_ds/io/raster/reader.py: 0%

1# -*- coding: utf-8 -*- 

2 

3# py_tools_ds - A collection of geospatial data analysis tools that simplify standard 

4# operations when handling geospatial raster and vector data as well as projections. 

5# 

6# Copyright (C) 2016-2021 

7# - Daniel Scheffler (GFZ Potsdam, daniel.scheffler@gfz-potsdam.de) 

8# - Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences Potsdam, 

9# Germany (https://www.gfz-potsdam.de/) 

10# 

11# This software was developed within the context of the GeoMultiSens project funded 

12# by the German Federal Ministry of Education and Research 

13# (project grant code: 01 IS 14 010 A-C). 

14# 

15# Licensed under the Apache License, Version 2.0 (the "License"); 

16# you may not use this file except in compliance with the License. 

17# You may obtain a copy of the License at 

18# 

19# http://www.apache.org/licenses/LICENSE-2.0 

20# 

21# Unless required by applicable law or agreed to in writing, software 

22# distributed under the License is distributed on an "AS IS" BASIS, 

23# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 

24# See the License for the specific language governing permissions and 

25# limitations under the License. 

26 

27import multiprocessing 

28import ctypes 

29import numpy as np 

30from osgeo import gdal 

31 

32from ...numeric.array import get_array_tilebounds 

33 

34__author__ = "Daniel Scheffler" 

35 

36 

37shared_array = None 

38 

39 

40def init_SharedArray_in_globals(dims): 

41 rows, cols = dims 

42 global shared_array 

43 shared_array_base = multiprocessing.Array(ctypes.c_double, rows * cols) 

44 shared_array = np.ctypeslib.as_array(shared_array_base.get_obj()) 

45 shared_array = shared_array.reshape(rows, cols) 

46 

47 

48def fill_arr(argDict, def_param=shared_array): 

49 pos = argDict.get('pos') 

50 func = argDict.get('func2call') 

51 args = argDict.get('func_args', []) 

52 kwargs = argDict.get('func_kwargs', {}) 

53 

54 (rS, rE), (cS, cE) = pos 

55 shared_array[rS:rE + 1, cS:cE + 1] = func(*args, **kwargs) 

56 

57 

58def gdal_read_subset(fPath, pos, bandNr): 

59 (rS, rE), (cS, cE) = pos 

60 ds = gdal.Open(fPath) 

61 data = ds.GetRasterBand(bandNr).ReadAsArray(cS, rS, cE - cS + 1, rE - rS + 1) 

62 del ds 

63 return data 

64 

65 

66def gdal_ReadAsArray_mp(fPath, bandNr, tilesize=1500): 

67 ds = gdal.Open(fPath) 

68 rows, cols = ds.RasterYSize, ds.RasterXSize 

69 del ds 

70 

71 init_SharedArray_in_globals((rows, cols)) 

72 

73 tilepos = get_array_tilebounds(array_shape=(rows, cols), tile_shape=[tilesize, tilesize]) 

74 fill_arr_argDicts = [{'pos': pos, 'func2call': gdal_read_subset, 'func_args': (fPath, pos, bandNr)} for pos in 

75 tilepos] 

76 

77 with multiprocessing.Pool() as pool: 

78 pool.map(fill_arr, fill_arr_argDicts) 

79 pool.close() 

80 pool.join() 

81 

82 return shared_array