python 创建要素类的随机样本

Posted 2021-05-09

import arcpy
import numpy as np

def randomFCSample(fc, fd='sample_fd', sample_field='OBJECTID', sample_pct=10):
  """Return a randomish sample of a feature class as a feature layer

    Parameters:
    fc (str): Input feature class to sample
    fd (str): Name of output feature layer
    sample_field (int): Numeric field to sample values from
    sample_pct (float): Percentage of feature class to sample  

    Returns:
    feature layer sample of input feature class

  """
  count_class = arcpy.GetCount_management(fc)
  count = int(count_class[0])
  random_vals = np.random.choice(count, int(count*(sample_pct/100)))
  arcpy.MakeFeatureLayer_management(fc,
                                    fd + "_" + str(sample_pct) + 'pct',
                                    sample_field + ' IN ' + str(tuple(random_vals))
                                    )