71 lines
2.1 KiB
Go
71 lines
2.1 KiB
Go
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/*
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Package geojson is a library for encoding and decoding GeoJSON into Go structs.
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Supports both the json.Marshaler and json.Unmarshaler interfaces as well as helper functions
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such as `UnmarshalFeatureCollection`, `UnmarshalFeature` and `UnmarshalGeometry`.
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*/
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package geojson
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import (
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"encoding/json"
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)
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// A FeatureCollection correlates to a GeoJSON feature collection.
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type FeatureCollection struct {
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Type string `json:"type"`
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BoundingBox []float64 `json:"bbox,omitempty"`
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Features []*Feature `json:"features"`
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CRS map[string]interface{} `json:"crs,omitempty"` // Coordinate Reference System Objects are not currently supported
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}
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// NewFeatureCollection creates and initializes a new feature collection.
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func NewFeatureCollection() *FeatureCollection {
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return &FeatureCollection{
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Type: "FeatureCollection",
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Features: make([]*Feature, 0),
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}
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}
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// AddFeature appends a feature to the collection.
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func (fc *FeatureCollection) AddFeature(feature *Feature) *FeatureCollection {
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fc.Features = append(fc.Features, feature)
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return fc
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}
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// MarshalJSON converts the feature collection object into the proper JSON.
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// It will handle the encoding of all the child features and geometries.
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// Alternately one can call json.Marshal(fc) directly for the same result.
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func (fc FeatureCollection) MarshalJSON() ([]byte, error) {
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type featureCollection FeatureCollection
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fcol := &featureCollection{
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Type: "FeatureCollection",
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}
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if fc.BoundingBox != nil && len(fc.BoundingBox) != 0 {
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fcol.BoundingBox = fc.BoundingBox
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}
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fcol.Features = fc.Features
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if fcol.Features == nil {
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fcol.Features = make([]*Feature, 0) // GeoJSON requires the feature attribute to be at least []
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}
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if fc.CRS != nil && len(fc.CRS) != 0 {
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fcol.CRS = fc.CRS
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}
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return json.Marshal(fcol)
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}
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// UnmarshalFeatureCollection decodes the data into a GeoJSON feature collection.
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// Alternately one can call json.Unmarshal(fc) directly for the same result.
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func UnmarshalFeatureCollection(data []byte) (*FeatureCollection, error) {
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fc := &FeatureCollection{}
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err := json.Unmarshal(data, fc)
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if err != nil {
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return nil, err
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}
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return fc, nil
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}
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