Query Location by Radius with GeoFire

问题

I know this is a basic question, but I’m having a lot of trouble with it nonetheless.

I have a Firebase database storing community events. Each event node has a geo location node (created with GeoFire) called eventPlace (see screenshot below).

Using GeoFire (and javascript), how would I query the entire database and get all events within a certain location/radius? Is this possible, given the way the data is stored? Or do I need to move all the location nodes to a common node (eventPlaces??) and query that single parent node?

Note that I am not seeking real-time data. These locations are stored previously and don’t change very often.

Thanks in advance…

回答1:

As it stands right now geofire sort of serves as an index to make geoqueries on, and provides the key of the document you want (which would be stored in a separate "collection").

You should be using geofire and a separate "collection" (call it eventPlaces)

var firebaseRef = firebase.database().ref('eventPlaces');
var geoFire = new GeoFire(firebaseRef);

Now you can use it as an index for your events, and can add items to it like so.

geoFire.set('-K_Pp-3RBJ58VkHGsL5P', [40.607765, -73.758949]);

Your Firebase RTDB will look like this now:

{
   'events': {
        '-K_Pp-3RBJ58VkHGsL5P': {
            // All your data here
        }
    },
   'eventPlaces': {
        '-K_Pp-3RBJ58VkHGsL5P': {
            'g': 'dr5x186m7u',
            'l': [40.607765, -73.758949]
        }
    }
}

So finally when you do a query on your geoFire:

geoFire.query({
  center: [40.607765, -73.758949],
  radius: 10
}).on('key_entered', (key, location, distance) => {
  console.log(key + ' entered query at ' + location + ' (' + distance + ' km from center)');
});

You'll end up being returned the key of the doc, for which you can do a normal Firebase query for that individual doc.

来源：https://stackoverflow.com/questions/52027670/query-location-by-radius-with-geofire

标签

node.js

firebase

geofire