火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法

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#include
<math.h>

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const

double

x_pi
= 3.14159265358979324 * 3000.0 / 180.0;

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void

bd_encrypt(

double

gg_lat,

double

gg_lon,

double

&bd_lat,

double

&bd_lon)

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{

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double

x
= gg_lon,y = gg_lat; 

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double

z
=

sqrt

(x
* x + y * y) + 0.00002 *

sin

(y
* x_pi);

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double

theta
=

atan2

(y,
x) + 0.000003 *

cos

(x
* x_pi);

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bd_lon
= z *

cos

(theta)
+ 0.0065;

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bd_lat
= z *

sin

(theta)
+ 0.006;

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}

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void

bd_decrypt(

double

bd_lat,

double

bd_lon,

double

&gg_lat,

double

&gg_lon)

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{

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double

x
= bd_lon - 0.0065, y = bd_lat - 0.006;

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double

z
=

sqrt

(x
* x + y * y) - 0.00002 *

sin

(y
* x_pi);

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double

theta
=

atan2

(y,
x) - 0.000003 *

cos

(x
* x_pi);

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gg_lon
= z *

cos

(theta);

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gg_lat
= z *

sin

(theta);

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}