1 data() {
2 return {
3 PI: 3.14159265358979324,
4 x_pi: (3.14159265358979324 * 3000.0) / 180.0
5 }
6 },
7 methods: {
8 delta(lat, lon) {
9 // Krasovsky 1940
10 //
11 // a = 6378245.0, 1/f = 298.3
12 // b = a * (1 - f)
13 // ee = (a^2 - b^2) / a^2
14 const a = 6378245.0 // a: 卫星椭球坐标投影到平面地图坐标系的投影因子。
15 const ee = 0.00669342162296594323 // ee: 椭球的偏心率。
16 let dLat = this.transformLat(lon - 105.0, lat - 35.0)
17 let dLon = this.transformLon(lon - 105.0, lat - 35.0)
18 const radLat = (lat / 180.0) * this.PI
19 let magic = Math.sin(radLat)
20 magic = 1 - ee * magic * magic
21 const sqrtMagic = Math.sqrt(magic)
22 dLat = (dLat * 180.0) / (((a * (1 - ee)) / (magic * sqrtMagic)) * this.PI)
23 dLon = (dLon * 180.0) / ((a / sqrtMagic) * Math.cos(radLat) * this.PI)
24 return { lat: dLat, lon: dLon }
25 },
26 // WGS-84 to GCJ-02
27 gcj_encrypt(wgsLat, wgsLon) {
28 if (this.outOfChina(wgsLat, wgsLon)) {
29 return { lat: wgsLat, lon: wgsLon }
30 }
31 const d = this.delta(wgsLat, wgsLon)
32 return { lat: wgsLat + d.lat, lon: wgsLon + d.lon }
33 },
34 // GCJ-02 to WGS-84
35 gcj_decrypt(gcjLat, gcjLon) {
36 if (this.outOfChina(gcjLat, gcjLon)) {
37 return { lat: gcjLat, lon: gcjLon }
38 }
39 const d = this.delta(gcjLat, gcjLon)
40 return { lat: gcjLat - d.lat, lon: gcjLon - d.lon }
41 },
42 // GCJ-02 to WGS-84 exactly
43 gcj_decrypt_exact(gcjLat, gcjLon) {
44 const initDelta = 0.01
45 const threshold = 0.000000001
46 let dLat = initDelta
47 let dLon = initDelta
48 let mLat = gcjLat - dLat
49 let mLon = gcjLon - dLon
50 let pLat = gcjLat + dLat
51 let pLon = gcjLon + dLon
52 let wgsLat
53 let wgsLon
54 let i = 0
55 while (1) {
56 wgsLat = (mLat + pLat) / 2
57 wgsLon = (mLon + pLon) / 2
58 const tmp = this.gcj_encrypt(wgsLat, wgsLon)
59 dLat = tmp.lat - gcjLat
60 dLon = tmp.lon - gcjLon
61 if (Math.abs(dLat) < threshold && Math.abs(dLon) < threshold) {
62 break
63 }
64
65 if (dLat > 0) {
66 pLat = wgsLat
67 } else {
68 mLat = wgsLat
69 }
70 if (dLon > 0) {
71 pLon = wgsLon
72 } else {
73 mLon = wgsLon
74 }
75 if (++i > 10000) {
76 break
77 }
78 }
79 // console.log(i)
80 return { lat: wgsLat, lon: wgsLon }
81 },
82 // GCJ-02 to BD-09
83 bd_encrypt(gcjLat, gcjLon) {
84 const x = gcjLon
85 const y = gcjLat
86 const z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * this.x_pi)
87 const theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * this.x_pi)
88 const bdLon = z * Math.cos(theta) + 0.0065
89 const bdLat = z * Math.sin(theta) + 0.006
90 return { lat: bdLat, lon: bdLon }
91 },
92 // BD-09 to GCJ-02
93 bd_decrypt(bdLat, bdLon) {
94 const x = bdLon - 0.0065
95 const y = bdLat - 0.006
96 const z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * this.x_pi)
97 const theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * this.x_pi)
98 const gcjLon = z * Math.cos(theta)
99 const gcjLat = z * Math.sin(theta)
100 return { lat: gcjLat, lon: gcjLon }
101 },
102 // WGS-84 to Web mercator
103 // mercatorLat -> y mercatorLon -> x
104 mercator_encrypt: function(wgsLat, wgsLon) {
105 const x = (wgsLon * 20037508.34) / 180.0
106 let y =
107 Math.log(Math.tan(((90.0 + wgsLat) * this.PI) / 360.0)) /
108 (this.PI / 180.0)
109 y = (y * 20037508.34) / 180.0
110 return { lat: y, lon: x }
111 /*
112 if ((Math.abs(wgsLon) > 180 || Math.abs(wgsLat) > 90))
113 return null
114 var x = 6378137.0 * wgsLon * 0.017453292519943295
115 var a = wgsLat * 0.017453292519943295
116 var y = 3189068.5 * Math.log((1.0 + Math.sin(a)) / (1.0 - Math.sin(a)))
117 return {'lat' : y, 'lon' : x}
118 //*/
119 },
120 // Web mercator to WGS-84
121 // mercatorLat -> y mercatorLon -> x
122 mercator_decrypt: function(mercatorLat, mercatorLon) {
123 const x = (mercatorLon / 20037508.34) * 180.0
124 let y = (mercatorLat / 20037508.34) * 180.0
125 y =
126 (180 / this.PI) *
127 (2 * Math.atan(Math.exp((y * this.PI) / 180.0)) - this.PI / 2)
128 return { lat: y, lon: x }
129 /*
130 if (Math.abs(mercatorLon) < 180 && Math.abs(mercatorLat) < 90)
131 return null
132 if ((Math.abs(mercatorLon) > 20037508.3427892) || (Math.abs(mercatorLat) > 20037508.3427892))
133 return null
134 var a = mercatorLon / 6378137.0 * 57.295779513082323
135 var x = a - (Math.floor(((a + 180.0) / 360.0)) * 360.0)
136 var y = (1.5707963267948966 - (2.0 * Math.atan(Math.exp((-1.0 * mercatorLat) / 6378137.0)))) * 57.295779513082323
137 return {'lat' : y, 'lon' : x}
138 //*/
139 },
140 // two point's distance
141 distance(latA, lonA, latB, lonB) {
142 const earthR = 6371000.0
143 const x =
144 Math.cos((latA * this.PI) / 180.0) *
145 Math.cos((latB * this.PI) / 180.0) *
146 Math.cos(((lonA - lonB) * this.PI) / 180)
147 const y =
148 Math.sin((latA * this.PI) / 180.0) * Math.sin((latB * this.PI) / 180.0)
149 let s = x + y
150 if (s > 1) {
151 s = 1
152 }
153 if (s < -1) {
154 s = -1
155 }
156 const alpha = Math.acos(s)
157 const distance = alpha * earthR
158 return distance
159 },
160 outOfChina(lat, lon) {
161 if (lon < 72.004 || lon > 137.8347) {
162 return true
163 }
164 if (lat < 0.8293 || lat > 55.8271) {
165 return true
166 }
167 return false
168 },
169 transformLat(x, y) {
170 let ret =
171 -100.0 +
172 2.0 * x +
173 3.0 * y +
174 0.2 * y * y +
175 0.1 * x * y +
176 0.2 * Math.sqrt(Math.abs(x))
177 ret +=
178 ((20.0 * Math.sin(6.0 * x * this.PI) +
179 20.0 * Math.sin(2.0 * x * this.PI)) *
180 2.0) /
181 3.0
182 ret +=
183 ((20.0 * Math.sin(y * this.PI) + 40.0 * Math.sin((y / 3.0) * this.PI)) *
184 2.0) /
185 3.0
186 ret +=
187 ((160.0 * Math.sin((y / 12.0) * this.PI) +
188 320 * Math.sin((y * this.PI) / 30.0)) *
189 2.0) /
190 3.0
191 return ret
192 },
193 transformLon(x, y) {
194 let ret =
195 300.0 +
196 x +
197 2.0 * y +
198 0.1 * x * x +
199 0.1 * x * y +
200 0.1 * Math.sqrt(Math.abs(x))
201 ret +=
202 ((20.0 * Math.sin(6.0 * x * this.PI) +
203 20.0 * Math.sin(2.0 * x * this.PI)) *
204 2.0) /
205 3.0
206 ret +=
207 ((20.0 * Math.sin(x * this.PI) + 40.0 * Math.sin((x / 3.0) * this.PI)) *
208 2.0) /
209 3.0
210 ret +=
211 ((150.0 * Math.sin((x / 12.0) * this.PI) +
212 300.0 * Math.sin((x / 30.0) * this.PI)) *
213 2.0) /
214 3.0
215 return ret
216 }
217 }
218 }
