使用Firebase查找附近的latlng [英] Finding nearby latlng using firebase

问题描述

-uniqueid1
            latitude: 30.7188235
            longitude: 76.810132
-uniqueid2
            latitude: 30.7188235
            longitude: 76.810132

firebase中有1000条这样的记录，我想找到最接近特定long/lat的唯一标识.我开始使用startAt()和endAt()但没有成功，我们如何实现条件子句和多个查询.我在寻找的是

there are 1000 such records in firebase , I want to find uniqueids closest to a specific long/lat.I started using startAt() and endAt() but no success.How do we implement conditional clause and multiple queries.The query me looking for is

SELECT uniqueids from table where (lon-specific_lon)^2+(lat-specific_lat)^2<CONSTANT.

推荐答案

您正在寻找的内容是Firebase

What you're looking for is part of Firebase's Geofire library. It uses Geohashes to cleverly work around Firebase's limit that you can only query on a single value.

Geohashes 是一种将经度和纬度填充为适合范围查询的单个值的方法.

Geohashes are a way to stuff longitude and latitude into a single value that is suitable for range querying.

有关更多信息，请参见 Githfire的Github存储库.

See the Github repo for Geofire for more information.

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