如何在 Mongoose 模式中表示 MongoDB GeoJSON 字段？
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How does one represent MongoDB GeoJSON fields in a Mongoose Schema?
提问by Zugwalt
MongoDB 2.4 allows the use of GeoJSONobjects and a slew of neat functions and indexesthat I'd like to use.
MongoDB 2.4 允许使用GeoJSON对象以及我想使用的大量简洁的函数和索引。
It expects GeoJSON objects to be stored in the format like:
它期望 GeoJSON 对象以如下格式存储：
loc: {
type: 'Polygon',
coordinates: [[[-180.0, 10.0], [20.0, 90.0], [180.0, -5.0], [-30.0, -90.0]]]
}
So in Mongoose one would think the schema would be defined like:
因此，在 Mongoose 中，人们会认为架构将被定义为：
loc: { type: 'string', coordinates: [[['number']]] }
But this present two problems:
但这存在两个问题：
having a field called "type" screws up Mongoose's schema parsing because it allows defining fields in the form field: { type: , index: } etc.
Mongoose does not like nested arrays.
有一个名为“type”的字段会破坏 Mongoose 的模式解析，因为它允许在表单字段中定义字段：{ type: , index: } 等。
Mongoose 不喜欢嵌套数组。
One way to overcome this is to simply use mongoose.Schema.Types.Mixed, however I feel that there has got to be a better way!
克服这个问题的一种方法是简单地使用mongoose.Schema.Types.Mixed，但是我觉得必须有更好的方法！
采纳答案by aaronheckmann
You must used Mixed to represent arrays of arrays. There is an open ticketto support this in the future.
您必须使用 Mixed 来表示数组的数组。将来有一张公开票可以支持这一点。
@nevi_me is correct, you must declare the typeproperty as he described.
@nevi_me 是正确的，您必须type按照他的描述声明该属性。
Here's a gist: https://gist.github.com/aheckmann/5241574
这是一个要点：https: //gist.github.com/aheckmann/5241574
See the mongoose tests here for more ideas: https://github.com/LearnBoost/mongoose/blob/master/test/model.querying.test.js#L1931
有关更多想法，请参阅此处的猫鼬测试：https: //github.com/LearnBoost/mongoose/blob/master/test/model.querying.test.js#L1931
回答by Jed Watson
For reference, GeoJSON is officially supported in Mongoose 3.6
作为参考，Mongoose 3.6 正式支持 GeoJSON
Example (from the docs):
示例（来自文档）：
new Schema({ loc: { type: [Number], index: '2dsphere'}})
... then ...
... 然后 ...
var geojsonPoly = { type: 'Polygon', coordinates: [[[-5,-5], ['-5',5], [5,5], [5,-5],[-5,'-5']]] }
Model.find({ loc: { $within: { $geometry: geojsonPoly }}})
// or
Model.where('loc').within.geometry(geojsonPoly)
回答by Mark Stosberg
The mongoose-geojson-schemapackage was created to make it easy to have GeoJSON in Mongoose Schemas.
该猫鼬，以GeoJSON-架构包是为了让您轻松拥有以GeoJSON在猫鼬架构。
回答by arg20
Mongoose now officially supports this.
Mongoose 现在正式支持这一点。
In a nutshell, what you do is, for that schema, you use the typeKeysetting to tell mongoose to use a different key for type information. Here is an example:
简而言之，您所做的是，对于该模式，您使用typeKey设置告诉猫鼬使用不同的键来获取类型信息。下面是一个例子：
var schema = new Schema({
// Mongoose interpets this as 'loc is an object with 2 keys, type and coordinates'
loc: { type: String, coordinates: [Number] },
// Mongoose interprets this as 'name is a String'
name: { $type: String }
}, { typeKey: '$type' }); // A '$type' key means this object is a type declaration
So now instead of declaring type info with the typeproperty, you use $type. This works at the schema level so use it in the schemas that need it.
因此，现在不是type使用属性声明类型信息，而是使用$type. 这适用于模式级别，因此在需要它的模式中使用它。
回答by nevi_me
I'm about to start moving all my location references in my MongoDB from '2d'to GeoJSON, so I'll encounter the same problem.
我即将开始将我在 MongoDB 中的所有位置引用从'2d'GeoJSON 移动，所以我会遇到同样的问题。
- Regarding the
typeproblem, you have to follow what I did below to get it working. Mongoose correctly recognises it as a string. - Nested arrays; I agree that
mongoose.Schema.Types.Mixedwill work, but I think you can try what I did below, let me know if it works. I'm not near a PC with mongo installed to try the schema out.
- 关于这个
type问题，你必须按照我在下面做的来让它工作。Mongoose 正确地将其识别为字符串。 - 嵌套数组；我同意这
mongoose.Schema.Types.Mixed会奏效，但我认为你可以尝试我在下面所做的，让我知道它是否有效。我没有靠近安装了 mongo 的 PC 来尝试架构。
Here's how I'd define the schema. The nested array can be tweaked to work, so let me know if it doesn't.
这是我定义架构的方式。可以调整嵌套数组以使其工作，所以如果没有，请告诉我。
var LocationObject = new Schema ({
'type': {
type: String,
required: true,
enum: ['Point', 'LineString', 'Polygon'],
default: 'Point'
},
coordinates: [
[
{ type: [ Number ]
]
]
});
If you get undesired results in the nesting of the Array, try this out instead. Basically nesting in deeper.
如果您在 的嵌套中得到不想要的结果Array，请改用此方法。基本上嵌套更深。
coordinates: [
{ type: [
{ type: [ Number ] }
] }
]
