java,经纬度转换行政区域

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篇一：geohash算法经纬度转换

geohash算法经纬度转换

geohash在查找周围朋友，lbs中有很多的应用，在网上查找到geohash算法实现分享给大家。

importjava.util.hashmap;

importjava.util.map;

publicclassgeohashkit{

//geohashscharmap

//noasislsos

//oldmacdonalwouldntbehappy

privatestaticchar[]_base32={0,1,2,3,4,5,6,7,

8,9,b,c,d,e,f,g,h,j,k,m,n,

p,q,r,s,t,u,v,w,x,y,z};

privatefinalstaticmap_decodemap=newhashmap();static

{

intsz=_base32.length;

for(inti=0;i _decodemap.put(_base32[i],i);

}

}

privatestaticintprecision=12;

privatestaticint[]bits={16,8,4,2,1};

publicstaticvoidmain(string[]args){

geohashkitghf=newgeohashkit();

stringgc1=ghf.encode(31.277631,120.53916300000003);

stringgc2=ghf.encode(51.4797,-0.0124);

system.out.println(gc1);

system.out.println(gc2);

double[]gd1=ghf.decode(gc1);

double[]gd2=ghf.decode(gc2);

system.out.println(gd1[0]

+","+gd1[1]);

system.out.println(gd2[0]+","+gd2[1]);

}

publicstaticstringencode(doublelatitude,doublelongi

double[]lat_interval={-90.0,90.0};

double[]lon_interval={-180.0,180.0}; stringbuildergeohash=newstringbuilder(); booleanis_even=true;

intbit=0,ch=0;

while(geohash.length() doublemid=0.0; if(is_even){

mid=(lon_interval[0]+lon_interval[1])/2;

ch|=bits[bit];

lon_interval[0]=mid;

}else{

lon_interval[1]=mid;

}

}else{

mid=(lat_interval[0]+lat_interval[1])/2;

if(latitude>mid){

ch|=bits[bit];

lat_interval[0]=mid;

}else{

lat_interval[1]=mid;

}

is_even=is_evenfalse:true;

if(bit bit++;

}else{

geohash.append(_base32[ch]);

bit=0;

ch=0;

}

}

returngeohash.tostring();

}

publicstaticdouble[]decode(stringgeohash){

double[]ge=decode_exactly(geohash);

doublelat,lon,lat_err,lon_err;

lat=ge[0];

lon=ge[1];

lat_err=ge[2];

lon_err=ge[3];

doublelat_precision=math.max(1,math.round(-math.log 10(lat_err)))-1;doublelon_precision=math.max(1,math .round(-math.log10(lon_err)))-1;lat=getprecision(la

t,lat_precision);

lon=getprecision(lon,lon_precision);

returnnewdouble[]{lat,lon};

}

publicstaticdouble[]decode_exactly(stringgeohash){ double[]lat_interval={-90.0,90.0};

double[]lon_interval={-180.0,180.0};

doublelat_err=90.0;

doublelon_err=180.0;

intsz=geohash.length();

intbsz=bits.length;

doublelatitude,longitude;

for(inti=0;i

intcd=_decodemap.get(geohash.charat(i));

for(intz=0;z intmask=bits[z];

if(is_even){

lon_err/=2;

if((cd

}else{

lon_interval[1]=(lon_interval[0]+lon_interval[1])/2;