Mercurial Hosting > traffic-intelligence
view python/utils.py @ 25:28e546861263
added Point class and modified trajectory accordingly
author | Nicolas Saunier <nico@confins.net> |
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date | Sat, 05 Dec 2009 12:08:25 -0500 |
parents | 6fb59cfb201e |
children | 44689029a86f |
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#! /usr/bin/env python ''' Generic utilities.''' #from numpy import * #from pylab import * __metaclass__ = type commentChar = '#'; # maths def segmentIntersection(s1, s2): '''Returns the intersecting point, None otherwise format for a segment is [[x1, x2], [y1,y2]] >>> segmentIntersection([[0, 1], [0,1]], [[0, 1], [1,2]]) >>> segmentIntersection([[0, 1], [1,0]], [[0, 1], [2,1]]) >>> segmentIntersection([[0, 2], [0,0]], [[1, 1], [-1,1]]) [1.0, 0.0] >>> segmentIntersection([[0, 2], [0,0]], [[1, 1], [1,2]]) ''' from numpy import matrix from numpy.linalg import linalg, det ds1 = [s1[0][1]-s1[0][0], s1[1][1]-s1[1][0]] ds2 = [s2[0][1]-s2[0][0], s2[1][1]-s2[1][0]] A = matrix([[ds1[1], -ds1[0]], [ds2[1], -ds2[0]]]) B = matrix([[ds1[1]*s1[0][0]-ds1[0]*s1[1][0]], [ds2[1]*s2[0][0]-ds2[0]*s2[1][0]]]) if linalg.det(A) == 0:#crossProduct(ds1, ds2) == 0: return None else: intersection = linalg.solve(A,B) if (intersection[0,0] >= s1[0][0] and intersection[0,0] <= s1[0][1] and intersection[0,0] >= s2[0][0] and intersection[0,0] <= s2[0][1] and intersection[1,0] >= s1[1][0] and intersection[1,0] <= s1[1][1] and intersection[1,0] >= s2[1][0] and intersection[1,0] <= s2[1][1]): return [intersection[0,0], intersection[1,0]] else: return None def crossProduct(l1, l2): return l1[0]*l2[1]-l1[1]*l2[0] # file I/O def openCheck(filename, option = 'r', quit = False): '''Open file filename in read mode by default and checks it is open >>> f = openCheck('non_existant_file.txt') File non_existant_file.txt could not be opened. ''' try: return open(filename, option) except IOError: print 'File %s could not be opened.' % filename if quit: from sys import exit exit() return None def readline(f): '''Modified readline function to skip comments.''' s = f.readline() while (len(s) > 0) and s.startswith(commentChar): s = f.readline() return s.strip() def removeExtension(filename, delimiter = '.'): '''Returns the filename minus the extension (all characters after last .) >>> removeExtension('test-adfasdf.asdfa.txt') 'test-adfasdf.asdfa' >>> removeExtension('test-adfasdf') 'test-adfasdf' ''' i = filename.rfind(delimiter) if i>0: return filename[:i] else: return filename def listfiles(dirname, extension, remove = False): '''Returns the list of files with the extension in the directory dirname If remove is True, the filenames are stripped from the extension''' from os import listdir tmp = [f for f in listdir(dirname) if f.endswith(extension)] tmp.sort() if remove: return [removeExtension(f, extension) for f in tmp] else: return tmp def removeFile(filename): '''Deletes the file while avoiding raising an error if the file does not exist''' if (os.path.exists(filename)): os.remove(filename) def invertHomography(homography): 'Returns an inverted homography' invH = inv(homography) invH /= invH[2,2] return invH def project(homography, p): '''Returns the coordinates of the projection of the point p through homography''' from numpy.core._dotblas import dot from numpy.core.multiarray import array from numpy.lib.function_base import insert if (homography!=None) and (len(homography)>0): pAugmented = insert(array(p), [2],[1], axis=0) projected = dot(homography, pAugmented) projected[0] /= projected[2] projected[1] /= projected[2] else: projected = p return projected[:2] def printPoint(x,y): return '(%f,%f)'%(x,y) def plotPolygon(poly, options = ''): from numpy.core.multiarray import array from matplotlib.pyplot import plot from shapely.geometry import Polygon tmp = array(poly.exterior) plot(tmp[:,0], tmp[:,1], options) if __name__ == "__main__": import doctest import unittest #suite = doctest.DocFileSuite('tests/ubc_utils.txt') suite = doctest.DocTestSuite() unittest.TextTestRunner().run(suite) #doctest.testmod() #doctest.testfile("example.txt")