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GPS地图生成03之数据获取

作者:互联网

 

 

 

 

1. 引言

 

六只脚是国内著名的户外网站,拥有大量的户外GPS轨迹路线,网址为:http://www.foooooot.com/ 图片.png

 

2. 数据分析

 

2.1 获取所有轨迹

 

搜索关键词岳麓山

图片.png

 

可以发现,每页具有三十个轨迹记录

观察第二页的网址我们可以发现网址为:http://www.foooooot.com/search/trip/all/1/all/time/descent/?page=2&keyword=%E5%B2%B3%E9%BA%93%E5%B1%B1 不难发现其规律:

我们不妨测试page为50的情况,在浏览器输入http://www.foooooot.com/search/trip/all/1/all/time/descent/?page=50&keyword=%E5%B2%B3%E9%BA%93%E5%B1%B1

图片.png

小结:我们可以通过不断增加page的数字,直至某一页不满足三十个轨迹记录,获取该关键词所有的轨迹记录

 

2.2 获取轨迹ID

 

点击某个具体的轨迹详情:

图片.png

可以看到每一页具体的轨迹页面的网址是由轨迹ID构造的,诸如:http://www.foooooot.com/trip/1448263/

从刚才的列表界面我们就可以找到每个轨迹ID:

图片.png

 

2.3 获取轨迹数据

 

我们打开浏览器控制台(按F12),点击到网络记录界面,刷新网址:

图片.png

从网络请求记录中我们发现有两个XHR异步请求其名字很像轨迹数据,点开查看:

图片.png

可以看到,这个trackjson就是轨迹的JSON数据:

图片.png

这个footprintsjson就是足迹数据,也就是拍照的那种数据:

图片.png

 

2.4 字段解释

 

对于trackjson,前三列个数据项可以快速判断为时间戳和经纬度,对于后面三个数据项,结合网页数据:

图片.png

可以判断分别为高程,速度和里程

 

对于footprintsjson,可以判断前几列数据项分别为时间戳、经纬度、高程、名字、缩略图、详情图,后面几项笔者认为没啥作用

图片.png

 

3. 数据爬取

 

经过上面的数据分析,爬取轨迹数据主要就是通过page和keyword构造网址获取轨迹ID,通过轨迹ID构造地址获取trackjson和footprintsjson

 

笔者此处基于Python,使用requests库发送http请求,使用Xpath解析界面提取数据

 

3.1 引入库

In [1]:
import requests
from lxml import etree
import json
import time
   

3.2 获取所有轨迹ID

In [2]:
page_num = 1
track_num_arr = []
keyword = "岳麓山"
headers = {'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36'}
page_url = "http://www.foooooot.com/search/trip/all/1/all/time/descent/?page=" + str(page_num) + "&keyword=" + keyword
  In [9]:
next_page = True
while(next_page):
    response = requests.get(page_url,timeout=5, headers=headers)
    tree = etree.HTML(response.text)
    trip_list = tree.xpath('//p[@class="trip-title"]/a/@href')
    if(len(trip_list) == 30):
        page_num = page_num + 1
        page_url = "http://www.foooooot.com/search/trip/all/1/all/time/descent/?page=" + str(page_num) + "&keyword=" + keyword
    else:
        next_page = False
    for trip in trip_list:
        track_num_arr.append(trip.split('/')[2])
    time.sleep(6)
In [10]:
print(len(track_num_arr))
 
1170
 

可以看到有1170条轨迹数据

 

3.3 获取轨迹数据

In [37]:
num = 0 
for track_num in track_num_arr:
    try:
        #设置重连次数
        requests.adapters.DEFAULT_RETRIES = 5
        s = requests.session()
        # 设置连接活跃状态为False
        s.keep_alive = False
        time.sleep(6)
        footprint_url = "http://www.foooooot.com/trip/" + str(track_num) + "/footprintsjson/"
        trackjson_url = "http://www.foooooot.com/trip/" + str(track_num) + "/trackjson/"
        footprint_res = requests.get(footprint_url,headers=headers,stream=False,timeout= 10)
        trackjson_res = requests.get(trackjson_url,headers=headers,stream=False,timeout= 10)
        try:
            trackjson = json.loads(trackjson_res.text)
            footprint = json.loads(footprint_res.text)
            with open("./trackdata/origin/trackjson" +  str(track_num) + ".json","w") as tf:
                json.dump(trackjson,tf)
            with open("./trackdata/origin/footprint" +  str(track_num) + ".json","w") as ff:
                json.dump(footprint,ff)
            for track in trackjson:
                with open("./trackdata/trip_" +  str(track_num) + ".txt","a") as tf:
                    tf.write(str(track[1]) + " " + str(track[2]) + " " + str(track[3]) + " " + str(int(track[0])) + "\n")
                with open("./trackdata/all.csv","a") as af:
                    af.write(str(num) + "," + str(track[2]) + "," + str(track[1]) + "," + str(track[3]) + "," + str(track_num) + "," + str(int(track[0])) + "\n")
                    num = num + 1
            # print("DONE: " + track_num)
            # 关闭请求  释放内存
            footprint_res.close()
            trackjson_res.close()
            del(footprint_res)
            del(trackjson_res) 
        except Exception as we:
            print(we)
            print("ERROR: " + track_num)
            with open("./trackdata/error.txt","a") as af:
                af.write(str(track_num) + '\n')
            # 关闭请求  释放内存
            footprint_res.close()
            trackjson_res.close()
            del(footprint_res)
            del(trackjson_res) 
    except Exception as ce:
        print(ce)
        time.sleep(60)
 
Expecting value: line 1 column 1 (char 0)
ERROR: 3541376
Expecting value: line 1 column 1 (char 0)
ERROR: 3541373
Expecting value: line 1 column 1 (char 0)
ERROR: 3541372
Expecting value: line 1 column 1 (char 0)
ERROR: 3541371
Expecting value: line 1 column 1 (char 0)
ERROR: 3541430
Expecting value: line 1 column 1 (char 0)
ERROR: 3505289
Expecting value: line 1 column 1 (char 0)
ERROR: 5135959
Expecting value: line 1 column 1 (char 0)
ERROR: 3390423
Expecting value: line 1 column 1 (char 0)
ERROR: 3389498
Expecting value: line 1 column 1 (char 0)
ERROR: 3392149
Expecting value: line 1 column 1 (char 0)
ERROR: 3392065
Expecting value: line 1 column 1 (char 0)
ERROR: 3392040
   

4. 可视化

 

在QGIS中利用加载XY文件的方式加载all.csv文件,并设置OSM底图,预览GPS轨迹:

 

图片.png

标签:03,轨迹,track,地图,num,str,page,trackjson,GPS
来源: https://www.cnblogs.com/jiujiubashiyi/p/16177208.html