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How do you define a polygon in MongoDB?
The query returns pairs that are within the bounds of the polygon. The operator does not query for GeoJSON objects. To define the polygon, specify an array of coordinate points:
What are the restrictions on projection in MongoDB?
The find () and findAndModify () projection can accept aggregation expressions and syntax. MongoDB enforces additional restrictions with regards to projections. See Projection Restrictions for details. The projection parameter determines which fields are returned in the matching documents.
How to specify a field in a MongoDB document?
For fields in an embedded documents, you can specify the field using either: nested form; e.g. { field: { nestedfield: } } ( Starting in MongoDB 4.4) The _id field is included in the returned documents by default unless you explicitly specify _id: 0 in the projection to suppress the field.
Which is the only field you can exclude in MongoDB?
In projections that explicitly include fields, the _id field is the only field that you can explicitly exclude. In projections that explicitly excludes fields, the _id field is the only field that you can explicitly include; however, the _id field is included by default.
How does the custom geointersects work in MongoDB?
The custom MongoDB CRS uses a counter-clockwise winding order and allows $geoIntersects to support queries with a single-ringed GeoJSON polygon whose area is greater than or equal to a single hemisphere.
How to specify a single ringed GeoJSON in MongoDB?
To specify a single-ringed GeoJSON polygon with a custom MongoDB CRS, use the following prototype that specifies the custom MongoDB CRS in the $geometry expression:
When to use$ within or$ geowithin in MongoDB?
To query with a single-ringed GeoJSON polygon whose area is greater than a single hemisphere, the $geometry expression must specify the custom MongoDB coordinate reference system. For example: Deprecated since version 2.4: $geoWithin replaces $within in MongoDB 2.4.
How to specify the location of an object in MongoDB?
To specify GeoJSON data, use an embedded document with: a field named coordinates that specifies the object’s coordinates. If specifying latitude and longitude coordinates, list the longitude first and then latitude: Valid longitude values are between -180 and 180, both inclusive.
What kind of geospatial queries do MongoDB support?
MongoDB geospatial queries can interpret geometry on a flat surface or a sphere. 2dsphere indexes support only spherical queries (i.e. queries that interpret geometries on a spherical surface). 2d indexes support flat queries (i.e. queries that interpret geometries on a flat surface) and some spherical queries.
How to do spherical surface calculations in MongoDB?
MongoDB supports spherical surface calculations on legacy coordinate pairs via a 2dsphere index by converting the data to the GeoJSON Point type. To specify data as legacy coordinate pairs, you can use either an array ( preferred) or an embedded document.