1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
|
# -*- coding: utf-8 -*-
"""
***************************************************************************
raster.py
---------------------
Date : February 2013
Copyright : (C) 2013 by Victor Olaya and Alexander Bruy
Email : volayaf at gmail dot com
***************************************************************************
* *
* This program 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 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""
__author__ = 'Victor Olaya and Alexander Bruy'
__date__ = 'February 2013'
__copyright__ = '(C) 2013, Victor Olaya and Alexander Bruy'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import struct
from osgeo import gdal
from osgeo.gdalconst import *
def scanraster(layer, progress):
filename = unicode(layer.source())
dataset = gdal.Open(filename, GA_ReadOnly)
band = dataset.GetRasterBand(1)
nodata = band.GetNoDataValue()
for y in xrange(band.YSize):
progress.setPercentage(y / float(band.YSize) * 100)
scanline = band.ReadRaster(0, y, band.XSize, 1, band.XSize, 1,
band.DataType)
values = struct.unpack('f' * band.XSize, scanline)
for value in values:
if value == nodata:
value = None
yield value
def mapToPixel(mX, mY, geoTransform):
"""Convert map coordinates to pixel coordinates.
@param mX Input map X coordinate (double)
@param mY Input map Y coordinate (double)
@param geoTransform Input geotransform (six doubles)
@return pX, pY Output coordinates (two doubles)
"""
if geoTransform[2] + geoTransform[4] == 0:
pX = (mX - geoTransform[0]) / geoTransform[1]
pY = (mY - geoTransform[3]) / geoTransform[5]
else:
(pX, pY) = applyGeoTransform(mX, mY, invertGeoTransform(geoTransform))
return (int(pX), int(pY))
def pixelToMap(pX, pY, geoTransform):
"""Convert pixel coordinates to map coordinates.
@param pX Input pixel X coordinate (double)
@param pY Input pixel Y coordinate (double)
@param geoTransform Input geotransform (six doubles)
@return mX, mY Output coordinates (two doubles)
"""
(mX, mY) = applyGeoTransform(pX + 0.5, pY + 0.5, geoTransform)
return (mX, mY)
def applyGeoTransform(inX, inY, geoTransform):
"""Apply a geotransform to coordinates.
@param inX Input coordinate (double)
@param inY Input coordinate (double)
@param geoTransform Input geotransform (six doubles)
@return outX, outY Output coordinates (two doubles)
"""
outX = geoTransform[0] + inX * geoTransform[1] + inY * geoTransform[2]
outY = geoTransform[3] + inX * geoTransform[4] + inY * geoTransform[5]
return (outX, outY)
def invertGeoTransform(geoTransform):
"""Invert standard 3x2 set of geotransform coefficients.
@param geoTransform Input GeoTransform (six doubles - unaltered)
@return outGeoTransform Output GeoTransform (six doubles - updated)
on success, None if the equation is uninvertable
"""
# We assume a 3rd row that is [1 0 0]
# Compute determinate
det = geoTransform[1] * geoTransform[5] - geoTransform[2] * geoTransform[4]
if abs(det) < 0.000000000000001:
return
invDet = 1.0 / det
# Compute adjoint and divide by determinate
outGeoTransform = [0, 0, 0, 0, 0, 0]
outGeoTransform[1] = geoTransform[5] * invDet
outGeoTransform[4] = -geoTransform[4] * invDet
outGeoTransform[2] = -geoTransform[2] * invDet
outGeoTransform[5] = geoTransform[1] * invDet
outGeoTransform[0] = (geoTransform[2] * geoTransform[3] - geoTransform[0]
* geoTransform[5]) * invDet
outGeoTransform[3] = (-geoTransform[1] * geoTransform[3] + geoTransform[0]
* geoTransform[4]) * invDet
return outGeoTransform
|
