手机上报的经纬度，并不是所有的都是GPS格式的，有的是GCJ02、有的是Baidu等等，那么如何才能针对一个城市的数据进行全面的纠偏呢？首先需要建立一个纠偏库，之后使用纠偏库实现纠偏。
以GCJ02纠偏库需要以下步骤：
- 一、建立纠GCJ02纠偏为GPS的偏库
1）选择一个城市的范围，找到最大最小经度、纬度的范围，设置需要纠偏的精确度，比如我选择A城市做为示例设置其纠偏范围
double leftUpLng = 121.0127; double leftUpLat = 31.0850; double rightDownLng = 121.392234; double rightDownLat = 31.446334;
精确度：0.0001（以米为单位）
long lngOffsetScope = (long)((rightDownLng - leftUpLng) / 0.0001); long latOffsetScope = (long)((rightDownLat - leftUpLat) / 0.0001);
3）选纠偏函数
1 private void DoOffset(List<LatLngOffsetStruct> items)
2 {
3 string lats = string.Join(";", items.Select(m => m.GCJ02Lat).ToArray());
4 string lngs = string.Join(";", items.Select(m => m.GCJ02Lng).ToArray());
5
6 /**
7 批量纠偏接口(POST)
8 接口地址 http://api.zdoz.net/transmore.ashx
9 接口说明
10 批量纠偏，一次最大可纠偏1000个坐标点
11 参数
12 lats:维度，多个维度用“;”隔开
13 lngs:经度，多个经度用“;”隔开（要注意经纬度个数相等）
14 type:转换类型 【1.WGS -> GCJ】 【2.GCJ -> WGS】 【3.GCJ -> BD】 【4.BD -> GCJ】 【5.WGS -> BD】 【6.BD -> WGS】
15 返回值JSON
16 根据次序返回一个json格式的数组
17 演示
18 参数：lats=34.123;34.332;55.231&lngs=113.123;112.213;115.321&type=1
19
20 返回：[{"Lng":113.12942937312582,"Lat":34.121761850760855},{"Lng":112.21911710957568,"Lat":34.3306763095054}, {"Lng":115.33036232125529,"Lat":55.232930158541052}]
21 */
22 string requestUri = "http://api.zdoz.net/transmore.ashx";
23 string parameter = string.Format("lats={0}&lngs={1}&type=2", lats, lngs);
24 int cursor = 0;
25
26 GOTO_AGAIN:
27 try
28 {
29 cursor++;
30
31 string httpContext = GetRequesetContext(requestUri, parameter);
32 // 返回：[{"Lng":113.12942937312582,"Lat":34.121761850760855},{"Lng":112.21911710957568,"Lat":34.3306763095054}, {"Lng":115.33036232125529,"Lat":55.232930158541052}]
33 string[] splitItems = httpContext.Split(new string[] { "[", "},{", "]" }, StringSplitOptions.RemoveEmptyEntries);
34
35 if (splitItems.Length < items.Count)
36 {
37 logger.Warn("出现拆分出的lat,lng的组合长度不够" + items.Count + "！！！");
38 }
39
40 int itemsNumber = splitItems.Length;
41 if (splitItems.Length > items.Count)
42 {
43 itemsNumber = items.Count;
44 }
45
46 for (var i = 0; i < itemsNumber; i++)
47 {
48 string[] lngLat = splitItems[i].Split(new string[] { "{", "}", "\"Lng\":", ",\"Lat\":" }, StringSplitOptions.RemoveEmptyEntries);
49 if (lngLat.Length != 2)
50 {
51 logger.Warn("出现" + splitItems[i] + "拆分出的lat,lng格式不正确！！！");
52 }
53
54 double lng = double.Parse(lngLat[0]);
55 double lat = double.Parse(lngLat[1]);
56
57 LatLngOffsetStruct item = items[i];
58 item.GpsLng = lng;
59 item.GpsLat = lat;
60 item.LatOffset = (item.GCJ02Lat - item.GpsLat).ToString();
61 item.LngOffset = (item.GCJ02Lng - item.GpsLng).ToString();
62 }
63 }
64 catch (Exception ex)
65 {
66 if (cursor < 5)
67 {
68 goto GOTO_AGAIN;
69 }
70
71 logger.Error("DoOffset失败次数超过5次:\r\n{0}\r\n{1}", ex.Message, ex.StackTrace);
72 }
73 }
74
75 private string GetRequesetContext(string requestUri, string parameter)
76 {
77 HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestUri);
78 request.Method = "post";
79 request.ContentType = "application/x-www-form-urlencoded";
80
81 byte[] payload = System.Text.Encoding.UTF8.GetBytes(parameter);
82 request.ContentLength = payload.Length;
83
84 Stream writer;
85 try
86 {
87 writer = request.GetRequestStream();
88 }
89 catch (Exception)
90 {
91 writer = null;
92 Console.Write("连接服务器失败!");
93 }
94
95 writer.Write(payload, 0, payload.Length);
96 writer.Close();
97
98 HttpWebResponse response;
99 try
100 {
101 response = (HttpWebResponse)request.GetResponse();
102 }
103 catch (WebException ex)
104 {
105 response = ex.Response as HttpWebResponse;
106 }
107
108 string httpContext = string.Empty;
109
110 using (Stream stream = response.GetResponseStream())
111 {
112 using (StreamReader reader = new StreamReader(stream))
113 {
114 httpContext = reader.ReadToEnd();
115 }
116 }
117
118 response.Close();
119
120 return httpContext;
121 }
定义纠偏结构体类：
public class LatLngOffsetStruct
{
public double GCJ02Lng { get; set; }
public double GCJ02Lat { get; set; }
public double GpsLng { get; set; }
public double GpsLat { get; set; }
public string LngOffset { get; set; }
public string LatOffset { get; set; }
}
4）就行纠偏的主要业务逻辑
1 public static void main(String[] args)
2 {
3 double leftUpLng = 121.0127;
4 double leftUpLat = 31.0850;
5 double rightDownLng = 121.392234;
6 double rightDownLat = 31.446334;
7
8 long lngOffsetScope = (long)((rightDownLng - leftUpLng) / 0.0001);
9 long latOffsetScope = (long)((rightDownLat - leftUpLat) / 0.0001);
10 long totalCalculateNumbers = lngOffsetScope * latOffsetScope;
11 long cursor = 0;
12
13 int previousProgress = 0;
14 List<LatLngOffsetStruct> items = new List<LatLngOffsetStruct>();
15 List<LatLngOffsetStruct> tempitems = new List<LatLngOffsetStruct>();
16 for (double lng = leftUpLng; lng < rightDownLng; lng += 0.0001)
17 {
18 for (double lat = leftUpLat; lat < rightDownLat; lat += 0.0001)
19 {
20 cursor++;
21
22 tempitems.Add(new LatLngOffsetStruct() { GCJ02Lat = lat, GCJ02Lng = lng });
23
24 if (tempitems.Count == 1000)
25 {
26 DoOffset(tempitems); //批量GCJ02坐标转化为GPS坐标
27
28 items.AddRange(tempitems);
29
30 tempitems = new List<LatLngOffsetStruct>();
31
32 if (items.Count > 100000)
33 {
34 DoInsert(items); //批量插入纠偏结果。
35 items = new List<LatLngOffsetStruct>();
36 }
37 }
38
39 int progress = (int)(cursor * 100 / totalCalculateNumbers);
40 if (progress > previousProgress)
41 {
42 previousProgress = progress;
43 this.backgroundWorker.ReportProgress(progress, "已经开始执行进度：" + progress + "%");
44 }
45 }
46 }
47
48 if (tempitems.Count > 0)
49 {
50 DoOffset(tempitems); //纠偏GCJ02 to GPS
51 items.AddRange(tempitems);
52 DoInsert(items); //入库
53 }
54 }
5）入库函数
1 private void DoInsert(List<LatLngOffsetStruct> tempitems)
2 {
3 try
4 {
5 DataTable schema = new DataTable();
6
7 schema.Columns.Add("GCJ02Lng", typeof(string));
8 schema.Columns.Add("GCJ02Lat", typeof(string));
9 schema.Columns.Add("LngOffset", typeof(string));
10 schema.Columns.Add("LatOffset", typeof(string));
11
12 foreach (var item in tempitems)
13 {
14 schema.Rows.Add(item.GCJ02Lng.ToString(), item.GCJ02Lat.ToString(), item.LngOffset, item.LatOffset);
15 }
16
17 using (SqlConnection connection = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString))
18 {
19 connection.Open();
20 using (SqlBulkCopy copy = new SqlBulkCopy(connection, SqlBulkCopyOptions.KeepIdentity, null))
21 {
22 copy.DestinationTableName = "dbo.Global_GCJ02_LngLatOffset";
23 copy.BatchSize = 10000;
24 copy.BulkCopyTimeout = 12 * 60 * 60;
25
26 copy.ColumnMappings.Clear();
27
28 copy.ColumnMappings.Add("GCJ02Lng", "GCJ02Lng");
29 copy.ColumnMappings.Add("GCJ02Lat", "GCJ02Lat");
30 copy.ColumnMappings.Add("LngOffset", "LngOffset");
31 copy.ColumnMappings.Add("LatOffset", "LatOffset");
32
33 copy.WriteToServer(schema);
34 }
35 }
36 }
37 catch (Exception ex)
38 {
39 logger.Debug("入库失败：\r\n{0}\r\n{1}", ex.Message, ex.StackTrace);
40 }
41 }
- 二、如何使用纠偏库实现GCJ02纠偏为GPS
1）首先需要根据经验建立一个库来记录下哪些host上报的经纬度是gcj02格式的经纬度，哪些host上报的经纬度是baidu坐标的经纬度等。
create table global_gcj02_host(
host string
);insert into global_gcj02_host(‘lbs.amap.com‘);.....
insert into global_gcj02_host(‘api.amap.com‘);
.....
2）使用host坐标系类型经验库(g_gcj02_host )、纠偏库(g_gcj02_lnglatoffset )来实现纠偏
需求：有一个库中存储的是待纠偏的数据表http_latlng
create table temp_baidu_result_for20170704 as
select t10.begintime,t10.host,t10.base_host,
(case when isnotnull(t11.lngoffset) then (t10.longitude-t11.lngoffset) else t10.longitude end)as longitude_offset,
(case when isnotnull(t11.latoffset) then (t10.latitude-t11.latoffset) else t10.latitude end) as latitude_offset
from
(
select t10.begintime,t10.endtime,t10.host,t10.longitude,t10.latitude,t11.host as base_host
from http_latlng t10 inner join g_gcj02_host as t11 on t10.host=t11.host
) t10
inner join g_gcj02_lnglatoffset t11 on rpad(t10.longitude,8,‘0‘)=rpad(t11.gcj02lng,8,‘0‘) and rpad(t10.latitude,7,‘0‘)=rpad(t11.gcj02lat,7,‘0‘);
时间： 2024-10-17 16:36:43