With the rapid popularization of various mobile terminals in recent years, there are more and more location-based services (LBS) and related applications, and one of the most basic technologies supporting these applications is the processing of location-based information.
For a detailed introduction to LBS and several general solutions, you can refer to: Symfony2 - Developing LBS Applications with MongoDB
This article mainly illustrates the implementation of finding nearby people using Perl language + MongoDB .
List of official API documentation involved:
The implementation steps are as follows:
1. Create a database table geoperson, including the location information field: loc (organized in GeoJSON format) , the data is as follows:
{
"_id": "o15041420964119780063",
"name": "stephen",
"head_fid": "f15022500199301140308001",
"loc": {
"type": "Point",
"coordinates": [
119.29647,
26.07421
]
},
"type": "geoperson",
"province": "福建省"
}
2、建立2dsphere索引
my $mocl = mdb()->get_collection("geoperson")->ensure_index({loc=>"2dsphere"});
3、查找附近2.5公里的人
my $rad = 2500; # 查找范围 2.5公里
my $max_size = 20; # 最多返回20条匹配数据
my $longitude = 119.31647; # 中心点坐标（经纬度）
my $latitude = 26.17421;
my $mocl = mdb()->get_collection("geoperson")->aggregate([
{
'$geoNear'=>{
'near'=> { type=>"Point", coordinates=>[$longitude, $latitude] }, # 也要采取GeoJSON格式
#'num'=> $max_size,#The default value is 100
'spherical'=>1, #Required if using a 2dsphere index.
# Specify the distance in meters if the specified point is GeoJSON
'maxDistance'=>$rad, # 单位是米
# The output field that contains the calculated distance.
'distanceField'=>"distance",
}
},
{ '$match'=> { "name"=> "lily" } } # 进一步过滤条件
{ '$sort'=> { "ut"=> -1 } } # 排序
]);
MongoDB原生支持地理位置索引，且高性能、支持复杂查询。
是不是很简单呀。