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99 lines
3.7 KiB
Python
99 lines
3.7 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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QGISUtils.py
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---------------------
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Date : August 2013
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Copyright : (C) 2013 by Alexander Bruy
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Email : alexander dot bruy at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = 'Alexander Bruy'
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__date__ = 'August 2013'
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__copyright__ = '(C) 2013, Alexander Bruy'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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import math
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from PyQt4.QtCore import *
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from qgis.core import *
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def mapToPixel(mX, mY, geoTransform):
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'''Convert map coordinates to pixel coordinates.
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@param mX Input map X coordinate (double)
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@param mY Input map Y coordinate (double)
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@param geoTransform Input geotransform (six doubles)
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@return pX, pY Output coordinates (two doubles)
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'''
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if geoTransform[2] + geoTransform[4] == 0:
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pX = (mX - geoTransform[0]) / geoTransform[1]
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pY = (mY - geoTransform[3]) / geoTransform[5]
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else:
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pX, pY = applyGeoTransform(mX, mY, invertGeoTransform(geoTransform))
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return int(pX), int(pY)
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def pixelToMap(pX, pY, geoTransform):
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'''Convert pixel coordinates to map coordinates.
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@param pX Input pixel X coordinate (double)
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@param pY Input pixel Y coordinate (double)
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@param geoTransform Input geotransform (six doubles)
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@return mX, mY Output coordinates (two doubles)
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'''
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mX, mY = applyGeoTransform(pX + 0.5, pY + 0.5, geoTransform)
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return mX, mY
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def applyGeoTransform(inX, inY, geoTransform):
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'''Apply a geotransform to coordinates.
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@param inX Input coordinate (double)
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@param inY Input coordinate (double)
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@param geoTransform Input geotransform (six doubles)
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@return outX, outY Output coordinates (two doubles)
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'''
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outX = geoTransform[0] + inX * geoTransform[1] + inY * geoTransform[2]
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outY = geoTransform[3] + inX * geoTransform[4] + inY * geoTransform[5]
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return outX, outY
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def invertGeoTransform(geoTransform):
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'''Invert standard 3x2 set of geotransform coefficients.
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@param geoTransform Input GeoTransform (six doubles - unaltered)
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@return outGeoTransform Output GeoTransform (six doubles - updated)
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on success, None if the equation is uninvertable
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'''
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# we assume a 3rd row that is [1 0 0]
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# compute determinate
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det = geoTransform[1] * geoTransform[5] - geoTransform[2] * geoTransform[4]
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if abs(det) < 0.000000000000001:
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return
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invDet = 1.0 / det
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# compute adjoint and divide by determinate
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outGeoTransform = [0, 0, 0, 0, 0, 0]
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outGeoTransform[1] = geoTransform[5] * invDet
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outGeoTransform[4] = -geoTransform[4] * invDet
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outGeoTransform[2] = -geoTransform[2] * invDet
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outGeoTransfrom[5] = geoTransform[1] * invDet
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outGeoTransform[0] = (geoTransform[2] * geoTransform[3] - geoTransform[0] * geoTransform[5]) * invDet
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outGeoTransform[3] = (-geoTransform[1] * geoTransform[3] + geoTransform[0] * geoTransform[4]) * invDet
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return outGeoTransform
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