我试图了解Arel的工作原理。如何使用Arel.spatial执行此PostGis查询？

auto flip = [&bitchips]() -> void
{
    for(auto i : bitchips) {
        i.flip();
    }
};

pta是 SELECT ST_asText(ST_ClosestPoint(track.path::geometry,pta.lonlat::geometry)) AS closet_point FROM tracks track,pois pta WHERE track.id = 2 AND pta.id = 2 之类的点
track.path是类似于t.geography "lonlat",limit: {:srid=>4326,:type=>"st_point",:geographic=>true}