如何处理Numpy的圆度?

时间:2012-05-23 08:07:34

标签: arrays numpy geometry degrees

我需要在numpy中计算一些方向数组。我将360度分为16组,每组分别为22.5度。我希望组中间的0度,即获得-11.25度到11.25度之间的方向。但问题是如何让这个群体在168.75度和-168.75度之间?

a[numpy.where(a<0)] = a[numpy.where(a<0)]+360
for m in range (0,3600,225):
        b = (a*10 > m)-(a*10 >= m+225).astype(float)    
        c = numpy.apply_over_axes(numpy.sum,b,0)

1 个答案:

答案 0 :(得分:1)

如果你想将数据分成16组,中间有0度,为什么要写for m in range (0,3600,225)

>>> [x/10. for x in range(0,3600,225)]
[0.0, 22.5, 45.0, 67.5, 90.0, 112.5, 135.0, 157.5, 180.0, 202.5, 225.0, 247.5,
 270.0, 292.5, 315.0, 337.5]
## this sectors are not the ones you want!

我会说你应该从for m in range (-1125,36000,2250)开始(请注意,现在我使用的是100因子而不是10),这会给你想要的组...

wind_sectors = [x/100.0 for x in range(-1125,36000,2250)]
for m in wind_sectors:
    #DO THINGS

我不得不说我真的不了解你的剧本及其目标...... 为了处理圆度,我建议像:

  • 一个条件,你把有问题的数据,即你必须处理零点过渡的那个;
  • 您放入所有其他数据的情况。

例如,在这种情况下,我打印的数组中属于每个扇区的所有元素:

import numpy

def wind_sectors(a_array, nsect = 16):
    step = 360./nsect
    init = step/2
    sectores = [x/100.0 for x in range(int(init*100),36000,int(step*100))]

    a_array[a_array<0] = a_arraya_array[a_array<0]+360

    for i, m in enumerate(sectores):
        print 'Sector'+str(i)+'(max_threshold = '+str(m)+')'
        if i == 0:
            for b in a_array:
                if b <= m or b > sectores[-1]:
                    print b

        else:
            for b in a_array:
                if b <= m and b > sectores[i-1]:
                    print b
    return "it works!"

# TESTING IF THE FUNCTION IS WORKING:
a = numpy.array([2,67,89,3,245,359,46,342])

print wind_sectors(a, 16)

# WITH NDARRAYS:

b = numpy.array([[250,31,27,306], [142,54,260,179], [86,93,109,311]])

print wind_sectors(b.flat[:], 16) 

关于 flat reshape 功能

>>> a = numpy.array([[0,1,2,3], [4,5,6,7], [8,9,10,11]])
>>> original = a.shape
>>> b = a.flat[:]
>>> c = b.reshape(original)
>>> a
array([[ 0,  1,  2,  3],
       [ 4,  5,  6,  7],
       [ 8,  9, 10, 11]])
>>> b
array([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11])
>>> c
array([[ 0,  1,  2,  3],
       [ 4,  5,  6,  7],
       [ 8,  9, 10, 11]])