请你解释一下earth_box函数的这种行为......或者我做错了什么?
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
从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
我现在的位置是离帝国大厦8000多米的自由女神像,但是
即使半径仅为 5558m,也选择返回 id 为 1 的行!你能解释一下这种行为或有什么问题吗?
=> 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
谢谢你
不
最佳答案
这里的问题是 earth_box 获得法定里程。
8324.42998846164米位于5.172560986623845法定英里附近
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) //doesn't return results
earth_box(ll_to_earth(40.689266, -74.044512), 9000/1.609) //does.