Postgresql earthdistance - 带半径的earth_box

Question

拜托，你能解释一下 earth_box 函数的这种行为......或者我做错了什么吗？

使用的数据

40.749276, -73.985643 = Empire State Building - is in my table
40.689266, -74.044512 = Statue of Liberty - is my current position in select - 8324m far from Empire State Building

我的 table

=> select id, latitude, longitude, title from requests;
 id | latitude  | longitude  |         title
----+-----------+------------+-----------------------
  1 | 40.749276 | -73.985643 | Empire State Building

帝国大厦到自由女神像的距离

=> SELECT id, latitude, longitude, title, earth_distance(ll_to_earth(40.689266, -74.044512), ll_to_earth(latitude, longitude)) as distance_from_current_location FROM requests ORDER BY distance_from_current_location ASC;
 id | latitude  | longitude  |         title         | distance_from_current_location
----+-----------+------------+-----------------------+--------------------------------
  1 | 40.749276 | -73.985643 | Empire State Building |               8324.42998846164

我现在的位置是距离帝国大厦8000多米的自由女神像，但是即使半径只有 5558m，也选择 ID 为 1 的返回行!你能解释一下这种行为或哪里出了问题吗？

=> SELECT id,latitude,longitude,title FROM requests WHERE earth_box(ll_to_earth(40.689266, -74.044512), 5558) @> ll_to_earth(requests.latitude, requests.longitude);
 id | latitude  | longitude  |         title
----+-----------+------------+-----------------------
  1 | 40.749276 | -73.985643 | Empire State Building

扩展和 postgresql 的版本

=> \dx
                                     List of installed extensions
      Name      | Version |   Schema   |                         Description
 ---------------+---------+------------+--------------------------------------------------------------  cube          | 1.0     | public     | data type for multidimensional
 cubes  earthdistance | 1.0     | public     | calculate great-circle
 distances on the surface of the Earth  plpgsql       | 1.0     |
 pg_catalog | PL/pgSQL procedural language

 => select version();
                                                                version
 --------------------------------------------------------------------------------------------------------------------------------------  PostgreSQL 9.4beta2 on x86_64-apple-darwin13.3.0, compiled by Apple
 LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn), 64-bit

谢谢没有

Answer 1

这里的问题是 earth_box 获得 Statute Miles。8324.42998846164 米接近 5.172560986623845 法定英里 Unit Converter

解决方案:将半径转换为法定英里单位

earth_box(ll_to_earth(40.689266, -74.044512), 5558/1.609)//不返回结果

earth_box(ll_to_earth(40.689266, -74.044512), 9000/1.609)//是。