英文:
GoLang Mongo GeoJSON
问题
在Golang中，使用MongoDB，我正在尝试存储GeoJSON对象，并同时保持2dsphere索引。
我无法声明一个通用的结构体来处理"Point"和"Polygon"，因为"Point"有一个[]float64类型的坐标字段，而"Polygon"有一个[][]float64类型的坐标字段。
你有任何关于如何声明这样的结构体的想法吗？
英文:
In Golang, with MongoDB, I am trying to store GeoJSON objects, while keeping a 2dsphere index.
I am unable to declare a generic struct that can handle both "Point" and "Polygon", since a "Point" have a []float64 coordinates field, while a "Polygon" have a [][]float64 coordinates field.
Do you have any idea on how to declare such a struct?
答案1
得分: 5
你可以尝试在结构体中将polygon和point的字段都定义为interface类型。我为你的情况创建了一个简单的程序，如下所示：
package mainimport ("fmt")type figure struct {name stringcoordinates interface{}}func main() {Point := figure{"Point", [2]float64{2.0, 7.88}}Polygon := figure{"Polygon", [2][2]float64{{2.0, 7.88}, {3.0, 7.88}}}fmt.Println(Point)fmt.Println(Polygon)}
输出结果为：
{Point [2 7.88]}{Polygon [[2 7.88] [3 7.88]]}
英文:
You can try using interface as field for both polygon and point in your struct. I created a simple program for your scenario as follows:
package mainimport ("fmt")type figure struct {name stringcoordinates interface{}}func main() {Point := figure{"Point", [2]float64{2.0, 7.88}}Polygon := figure{"Polygon", [2][2]float64{{2.0, 7.88}, {3.0, 7.88}}}fmt.Println(Point)fmt.Println(Polygon)}
Output:
{Point [2 7.88]}{Polygon [[2 7.88] [3 7.88]]}
答案2
得分: 0
首先，Ghoper的回答是**100%**正确的。包含Coordinates interface{}对我帮助很大。对于将来访问这里的任何人，这是我用于参考的GeoJson Feature Collection结构布局：
// Feature Collectiontype FeatureCollection struct {ID string `json:"_id,omitempty" bson:"_id,omitempty"`Features []Feature `json:"features" bson:"features"`Type string `json:"type" bson:"type"`}// Individual Featuretype Feature struct {Type string `json:"type" bson:"type"`Properties Properties `json:"properties" bson:"properties"`Geometry Geometry `json:"geometry" bson:"geometry"`}// Feature Propertiestype Properties struct {Name string `json:"name" bson:"name"`Height uint64 `json:"height" bson:"height"`Purchased bool `json:"purchased" bson:"purchased"`LastUpdated string `json:"last_updated" bson:"last_updated"`}// Feature Geometrytype Geometry struct {Type string `json:"type" bson:"type"`Coordinates interface{} `json:"coordinates" bson:"coordinates"`}
适用于所有的GeoJson类型（LineString、Point、Polygon、MultiPolygon）
英文:
Firstly, Ghoper's answer is 100% correct. The inclusion of Coordinates interface{} helped me massively. For anyone who visits here in the future this is my GeoJson Feature Collection struct layout for refernce:
// Feature Collectiontype FeatureCollection struct {ID string `json:"_id,omitempty" bson:"_id,omitempty"`Features []Feature `json:"features" bson:"features"`Type string `json:"type" bson:"type"`}// Individual Featuretype Feature struct {Type string `json:"type" bson:"type"`Properties Properties `json:"properties" bson:"properties"`Geometry Geometry `json:"geometry" bson:"geometry"`}// Feature Propertiestype Properties struct {Name string `json:"name" bson:"name"`Height uint64 `json:"height" bson:"height"`Purchased bool `json:"purchased" bson:"purchased"`LastUpdated string `json:"last_updated" bson:"last_updated"`}// Feature Geometrytype Geometry struct {Type string `json:"type" bson:"type"`Coordinates interface{} `json:"coordinates" bson:"coordinates"`}
Works for all GeoJson Types ( LineString, Point, Polygon, MultiPolygon )
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