I have two collections in my database: Post and Gallery. A Post has a single GeoJSON Point location, and a gallery is a collection of posts. The gallery's location is a GeoJSON Polygon bounding the gallery's posts (using quickhull algorithm). I now need to query for all galleries within x miles of a certain point, however I'm not getting any results even if I query from right next to my polygon.
I would like the behavior to be exactly the same as the following:
db.posts.find({
'location': {
$geoWithin: {
$centerSphere: [[-70, 30], 1000/3959]
}
}
});
Here, all posts within a the radius are returned. However, when I run the same type of function in this way, I am returned nothing, which is not correct:
db.galleries.find({
'location': {
$geoWithin: {
$centerSphere: [[-70, 30], 1000/3959]
}
}
});
One of my galleries has the following location (is 2dsphere index with 2dsphereIndexVersion = 2):
"location": {
"type": "Polygon",
"coordinates": [
[
[
-73.986882,
40.682829
],
[
-73.971089,
40.6672045
],
[
-73.955296,
40.65158
],
[
-73.986882,
40.682829
]
]
]
}
How do I query for location polygons that at least intersect with my radius?
I had the same problem and tried the exact same query that you initially tried. I'm not sure why it didn't work, but I was eventually able to get $near to do the job. Keep in mind that $near uses meters when calculating $maxDistance, so I had to convert my 10 mile desired distance to meters by multiplying by 1609.34. Here's the query that I ended up using:
db.maTowns.find(
{
'geometry': {
$near: {
$geometry: {
'type': "Point",
'coordinates': [ -71, 42 ]
},
$maxDistance: 10 * 1609.34
}
}
}
)
Select all polygons within the radius of a point
With the recent release of MongoDB version 3.6.0-rc0, you can now query GeoJSON LineStrings and Polygons with $geoWithin geospatial operator $centerSphere.
See also SERVER-27968 for more information about the change. Note that this change is pending to be backported.
Also maybe related for $geoIntersects and $centerSphere is ticket SERVER-30390
Related
I am not sure if there is a way to do this. I need to have a circle in mongodb and run a query against that with a box using $box to see if these two shapes overlap or not. However, Geojson does not support circles. What would be the best way to get this done?
The circle is stored like this:
places = {
...
"location": {
"type": "Point",
"coordinates": [
-79.390756,
43.706685
]
},
"radius": 100
}
I have two specific problems:
The first issue is that maxDistance is stored in the same object as the Geojson object and cannot be used in a $near query with $maxDistance; it only takes a number.
I do a partial postal code/ zip code search on Google Geocoding Api which returns a box with two corner coordinates like this:
"geometry": {
"bounds": {
"northeast": {
"lat": 43.710565,
"lng": -79.37363479999999
},
"southwest": {
"lat": 43.690848,
"lng": -79.40025399999999
}
}
As far as I know,I cannot use $box as it only works with $geoWithin.
Edit 1:
My initial plan with the circle and the box changed mainly because I did not find a suitable and efficient solution to this problem. Instead of checking if the circle overlaps with the box, now I check if a Geojson point is inside the circle as follows:
db.places.aggregate([
{"$geoNear": {near: { type: "Point", coordinates: [ -80.459293, 40.713640] },
distanceField: "dist.calculated", maxDistance: 100000,
key: 'myLocation', query: { 'SomeField': "..." }, spherical: true}},
{ "$match" : {$expr:{ $lte:['$dist.calculated', 'radius']}}}])
The problem here is that I d have to run a query within 100 KM first and then in another stage of the aggregation check the distance.
Is there a more efficient way to implement this? Thanks.
You can store a circle as point and radius. And you can use a $near query with a point and $maxDistance in meters which is the radius of the circle. See MongoDB Documentation.
Query to find all location, geometry field of the collection, at a certain distance from a point.
db.places.find(
{
location:
{ $near :
{
$geometry: { type: "Point", coordinates: [ -73.9667, 40.78 ] },
$maxDistance: 5000
}
}
}
)
Query to find if a given geometry (point, polygon(rect too)) in a query intersects with a geometry of a field in the collection.
//find quests bots that matches the users location
await Collection.find({ geometry:
{ $geoIntersects:
{
{
type: "Point",
coordinates: [
-73.99460599999999,
40.7347229
]
}
}
}
});
In my application I would like to query items that are close by (e.g. within 5km) to a coordinate and I tried to use $near to achieve that. With a quick look I thought it worked but after I tested it further it seems the query is somewhat inaccurate. Here is my setup:
I selected 2 coordinates that are a bit less than 5km apart from each other:
61.4644750214197, 23.8426943813556
61.497133399999996, 23.778528100000003
(At least according to tools like this, this or this the distance between those coordinates should be about ~4,99km)
I added one of the coordinates into empty "items" collection:
db.items.insert({
"geo" : {
"type" : "Point",
"coordinates" : [
61.4644750214197,
23.8426943813556
]
}
});
I added "2dsphere" index to the collection make geospatial queries possible:
db.items.createIndex( { geo : "2dsphere" } )
Finally, I used the other coordinate with $near query:
db.items.find({geo: {
$near: {
$geometry: {
type: "Point" ,
coordinates: [ 61.497133399999996, 23.778528100000003 ]
},
$maxDistance: 5000 // according to docs with '2dsphere' index and GeoJSON this is is meters
}
}}).count()
I expected the result to be 1 but instead it is 0. Even if I set $maxDistance to 7000 the result is still 0, but if I set it to 8000 the result will be 1.
Am I doing something wrong or are MongoDB geospatial queries (or just $near query?) that inaccurate? If so, is there a better way to get accurate results for this kind of query? This is my first time dealing with geospatial queries in MongoDB so there is probably a trivial explanation for my problem.
EDIT:
Basically I was dreaming of a functionality to show all items in map within X kilometres from users current location and X could be determined by user. It would be awkward if an item within 5km would not be visible even when the user wants to filter items within 7km.
I have tried most of the options for doing this query, like $centerSphere, $nearSphere and geoNear with similar results. They all seem to claim that the distance between my earlier mentioned coordinates is somewhere between 7-8km. I'm starting to think either 1. I'm missing some key peace of information about how distances work in general or 2. it simply is not possible to solve my problem with mongodb. Below are my queries for the other options:
$centerSphere (0 results with 5, 6 and 7km but 1 result with 8km):
db.items.find( { geo: {
$geoWithin: { $centerSphere: [ [ 61.497133399999996, 23.778528100000003 ], 5/6378.1 ]
}
}}).count()
geoNear (0 results with maxDistance 5000, 6000 and 7000 but 1 result with 8000):
db.runCommand(
{
geoNear: "items",
near: { type: "Point", coordinates: [ 61.497133399999996, 23.778528100000003 ] },
spherical: true,
maxDistance: 5000
}
)
I understand I am late to the party, but for all those who are facing similar issue
The problem here is that when you store that data into "coordinates", it must be in the [longitude, latitude] order because this is how mongodb works. https://docs.mongodb.com/manual/geospatial-queries/#spherical I just ran your example with reversed order of coordinates and it worked as expected.
db.items.insert({
"geo" : {
"type" : "Point",
"coordinates" : [
23.8426943813556,
61.4644750214197
]
}
});
And then i ran
db.items.find({geo: {
$near: {
$geometry: {
type: "Point" ,
coordinates: [ 23.778528100000003 , 61.497133399999996]
},
$maxDistance: 5000
}
}}).count()
The count here is 1:
Hope it helps
Guys I am trying to query all the polygons inside by bounding box but it simply returns 0.. It should be returning many polygons!
Alternatively I try to query a much larger bounding box and nothing happens!
My query is:
{
geometry:
{ $geoWithin:
{ $box:
[ [-73.995762,40.764826], [-73.934034,40.802038] ]
}
}
}
Notice that the very same query returns a valid result for geometries of type Point
to query all the polygons inside by bounding box but it simply returns 0
The $box operator for $geoWithin only supports documents based on grid coordinates and does not support GeoJSON shapes format.
the very same query returns a valid result for geometries of type Point
Depending on your documents structure, and how you are querying them, this is probably treated as being grid coordinates i.e. {geometry: [<long>, <lat>]}
This may not have worked for your polygons document because GeoJSON Polygons require an extra array wrapper. i.e. [[ [<long>, <lat>] ]] invalidating the grid coordinates format.
If your documents are in GeoJSON format, and you would like to select an area, you could utilise $geometry instead.
db.places.find(
{
'geometry': {
$geoWithin: {
$geometry: {
type : "Polygon" ,
coordinates: [ [ [ 0, 0 ], [ 3, 6 ], [ 6, 1 ], [ 0, 0 ] ] ]
}
}
}
}
)
Worth noting that MongoDB Compass geospatial visualisation currently (v1.6) does not support GeoJSON yet.
Here goes the answer:
$box do work with GeoJSON, but not with polygons! You need to generate a geometry with the $box instead.
Also, it always has to has the start point and point, so a 4-point polygon will have 5 coordinate tuples
BUT it gets trickier, it has to follow the right hand rule (anticlockwise).
TESTING GEOJSON WITH $BOX AND POINTS
my query:
{
geometry: {
$geoWithin: {
$box: [
[ -71.934034, 38.764826 ],
[ -75.995762, 43.802038 ]
]
}
}
}
I am trying to create a geospacial query in MongoDB that finds all circles (with varying radius) that overlap a single point.
My data looks something like this:
{
name: "Pizza Hut",
lat: <latitude>
lon: <longitude>
radius: 20
...
}
Basically, I am trying to do exactly what is described in this SO post but with MongoDB - Get all points(circles with radius), that overlap given point
geoIntersects (http://docs.mongodb.org/manual/reference/operator/query/geoIntersects/) looks like what I need. But in my case, the lat, lon, and radius is stored with each mongodb document and is not a fixed radius that is part of the query. Can this be done?
A different approach would be to find all documents whose distance from my query point is less than the value of their radius field (ie - 20km in the example above). How do you structure a MongoDB query where the calculated distance is part of the query filter criteria?
Thanks!
Well it would be nicer if you could use a GeoJSON object to represent the location but as of present the supported types are actually limited so a "Circle" type which would be ideal is not supported.
The closest you could do is a "Polygon" approximating a circle, but this is probably a little too much work to construct just for this query purpose. The other gotcha with doing this and then applying $geoIntersects is that the results will not be "sorted" by the distance from the query point. That seems to be the opposite of the purpose of finding the "nearest pizza" to the point of origin.
Fortunately there is a $geoNear operation added to the aggregation framework as of MongoDB 2.4 and greater. The good thing here is it allows the "projection" of a distance field in the results. This then allows you to do the logical filtering on the server to those points that are "within the radius" constraint to the distance from the point of origin. It also allows sorting on the server as well.
But you are still going to need to change your schema to support the index
db.places.insert({
"name": "Pizza Hut",
"location": {
"type": "Point",
"coordinates": [
151.00211262702942,
-33.81696995135973
]
},
"radius": 20
})
db.places.ensureIndex({ "location": "2dsphere" })
And for the aggregation query:
db.places.aggregate([
// Query and project distance
{ "$geoNear": {
"near": {
"type": "Point",
"coordinates": [
150.92094898223877,
-33.77654333272719
]
},
"distanceField": "distance",
"distanceMultiplier": 0.001,
"maxDistance": 100000,
"spherical": true
}},
// Calculate if distance is within delivery sphere
{ "$project": {
"name": 1,
"location": 1,
"radius": 1,
"distance": 1,
"within": { "$gt": [ "$radius", "$distance" ] }
}},
// Filter any false results
{ "$match": { "within": true } },
// Sort by shortest distance from origin
{ "$sort": { "distance": -1 } }
])
Basically this says,
*"out to 100 kilometers from a given location, find the places with their distance from that point. If the distance is within their "delivery radius" then return them, sorted by the closest"
There are other options you can pass to $geoNear in order to refine the result, as well as return more than the default 100 results if required and basically pass other options to query such as a "type" or "name" or whatever other information you have on the document.
I am writing a nodejs app involving geocodes ( ~50million places) stored in mongodb (using mongo native driver). For development I am testing with sample data (airports of the world ~45k locations http://www.ourairports.com/data/airports.csv ). I am following GeoJSON format and building 2dsphere index on location field(named "geometry"). Then I am doing a $geowithin query to find locations.
Evrything works as expected. The issue is that when I am querying for a polygon containing US, the query is taking around 4-6sec for returning 22845 locations.
db. airports.ensureIndex({ geometry: '2dsphere' })
db.airports.find({ geometry: { '$geoWithin': { '$geometry': { type: 'Polygon', coordinates: [ [ [ -127.32917843921399, 75.11297289119061 ], [ -71.32126356078601, 75.11297289119061 ], [ -71.32126356078601, 12.305525108809391 ], [ -127.32917843921399, 12.305525108809391 ], [ -127.32917843921399, 75.11297289119061 ] ] ] } } } })
I am sure that this cant be correct. This way I cant imagine response times with 50million points.
Would appreciate if someone can point me in direction to improve the performance of this.