实现根据gps数据计算停留点udaf函数

1.梳理、总结经纬度处理在Maxcompute平台上的实战应用，如根据gps轨迹数据计算停留点信息。
2.欢迎批评指正，跪谢一键三连！

1.参考代码

•   #!/usr/bin/env python
    # coding: utf-8
  
    import numpy as np
    from odps.udf import annotate
    from odps.udf import BaseUDAF
    from datetime import datetime
  
    @annotate('string,string,double,string->string')
    class ret_tld_by_gps(BaseUDAF):
        """计算停留点"""
        def new_buffer(self):
            return []
        def iterate(self, buffer, lati, longi, speed, gpstime):
            buffer.append([lati, longi, speed, gpstime])
        def merge(self, buffer, pbuffer):
            buffer += pbuffer
        def terminate(self, buffer): 
            buf = np.array(buffer)
            # try:
            buf2 = buf[:, 3]
            # return '%s %s %d %d' % (type(buf), type(buffer), buf.shape[0], buf.shape[1])
            index = np.lexsort((buf2,))
            buf3 = buf[index]
            # return '%s %d %d' % (','.join(buf3[0]), buf3.shape[0], buf3.shape[1])
            tld = []
            cnt, total_cnt, _flag = 0, 0, 0
            lati ,longi ,speed ,first_gpstime ,last_gpstime  = '','',0.0,'',''
            for rw in buf3:
                total_cnt += 1
                if float(rw[2])>0:
                    if _flag==1: # 速度变化点
                        if cnt==1:
                            last_gpstime = first_gpstime
                        # return '114, %d %s %d ' % (_flag, str(rw[2]), _flag)
                        # if (first_gpstime<>'') and (last_gpstime<>''):
                        diff_time = (datetime.strptime(last_gpstime, "%Y-%m-%d %H:%M:%S")-datetime.strptime(first_gpstime, "%Y-%m-%d %H:%M:%S")).seconds
                        # tld.append(','.join([lati, longi, first_gpstime, last_gpstime, '%.2f' % (diff_time/60.0) , str(cnt)]))
                        if (diff_time>=600) and (diff_time<=2400):
                            tld.append(','.join([lati, longi, first_gpstime, last_gpstime, '%.2f' % (diff_time/60.0) , str(cnt)]))
                        _flag, cnt = 0, 0
                elif float(rw[2])<=0: # 起始停留时间
                    cnt += 1
                    if _flag==0: # 持续为0点轨迹点
                        lati, longi = rw[0], rw[1]
                        first_gpstime, _flag = rw[3], 1
                    else:
                        last_gpstime = rw[3]
            if cnt!=1:
                # print('')
                # if (first_gpstime<>'') and (last_gpstime<>''):
                diff_time = (datetime.strptime(last_gpstime, "%Y-%m-%d %H:%M:%S")-datetime.strptime(first_gpstime, "%Y-%m-%d %H:%M:%S")).seconds
                if (diff_time>=600) and (diff_time<=2400):
                    tld.append(','.join([lati, longi, first_gpstime, last_gpstime, '%.2f' % (diff_time/60.0) , str(cnt)]))
            # return '%s' % (str(total_cnt))
            return '%s' % (';'.join(tld))