按最近的顺序排序-PostGIS，GeoRuby，spatial_adapter [英] Order by nearest - PostGIS, GeoRuby, spatial_adapter

问题描述

我正在尝试进行订单查询，以查找离current_user最近的记录.

I'm trying to do an order query that finds records nearest to the current_user.

我知道两点之间的距离是:current_location.euclidean_distance(@record.position)

I know the distance between the two points is: current_location.euclidean_distance(@record.position)

如何将其用于PostGIS(或active_record/spatial_adapter)查询?

How can I work this into a PostGIS (or active_record/spatial_adapter) query?

推荐答案

获取最接近的5个:

SELECT * FROM your_table 
ORDER BY ST_Distance(your_table.geom, ST_Geomfromtext(your point as wkt)) 
limit 5;

如果您有一个庞大的数据集，并且知道您不想进行进一步搜索，例如1公里，那么这样做将更有效:

If you have a big dataset and know that you don't want to search further than , say 1 km, the query will be more efficient if you do:

SELECT * FROM your_table 
WHERE ST_DWithin(your_table.geom, ST_Geomfromtext(your point as wkt, 1000)
ORDER BY ST_Distance(your_table.geom, ST_Geomfromtext(your point as wkt))  
limit 5;

/尼古拉斯

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