mongodb - 如何使用 Mongoid 执行 $geoIntersects 查询？

Question

我正在使用 Sinatra 和 mongoid 驱动程序，现在我正在尝试在 mongoid 中执行此查询，实际上我有一个名为 'geometry 的地理空间(多边形)字段':

db.states.find({
    geometry: {
        $geoIntersects: {
            $geometry: {
                type: "Point",
                coordinates: [-99.176524, 18.929204]
            }
        }
    }
})

其实这个查询是在 mongodb shell 中工作的。

但是，我想找到与给定点(Point-in-polygon)与 mongoid 或其他 ruby​​ 驱动程序相交的状态。

任何帮助将不胜感激。

谢谢。

Answer 1

我最近正在寻找这个，过了一段时间我发现了以下内容。也许其他人会对此有用..

$geoIntersects 现在在 mongoid 4.0.0.beta1 中实现，但没有很好的记录。我在原始更改日志中找到了这个:https://github.com/mongoid/origin/blob/master/CHANGELOG.md#new-features-1

query.geo_spacial(:location.intersects_line => [[ 1, 10 ], [ 2, 10 ]])
query.geo_spacial(:location.intersects_point => [[ 1, 10 ]])
query.geo_spacial(:location.intersects_polygon => [[ 1, 10 ], [ 2, 10 ], [ 1, 10 ]])
query.geo_spacial(:location.within_polygon => [[ 1, 10 ], [ 2, 10 ], [ 1, 10 ]])

和一个提交:https://github.com/mongoid/origin/commit/30938fad644f17fe38f62cf90571b78783b900d8

 # Add a $geoIntersects selection. Symbol operators must be used as shown in
 # the examples to expand the criteria.
 #
 # @note The only valid geometry shapes for a $geoIntersects are: :line,
 #   :point, and :polygon.
 # ...
 # @example Add a geo intersect criterion for a point.
 #   query.geo_intersects(:location.point => [[ 1, 10 ]])

在我的项目中，我有 mongoid (4.0.0.beta1) 和 origin (2.1.0)我有一个模型多边形

class Polygon
  include Mongoid::Document
  # some fields 

  embeds_many :loc

  # coordinates is an array of two points: [10, 12]
  def find_polygons_with_point(coordinates)
    # This is where the magic happens!
    Polygon.all.geo_spacial(:loc.intersects_point => coordinates)
  end

end

还有一个模型 Loc

class Loc
  field :type, type: String #Need to be set to 'Polygon' when creating a new location.
  field :coordinates, type: Array
  # For some reason the array has to be in the format
  # [ [ [1,1], [2,3], [5,3], [1,1] ] ]
  # And the first coordinate needs to be the same as the last
  # to close the polygon

  embedded_in :polygon

  index({ coordinates: "2d" }, { min: -200, max: 200 }) #may not need min/max
end

此代码返回包含该点的所有多边形。

可能有更优雅的方式来做到这一点。如果是这样，我想听听:)