Class: GeoJSON

ol/format/GeoJSON~GeoJSON


import GeoJSON from 'ol/format/GeoJSON';

Feature format for reading and writing data in the GeoJSON format.

new GeoJSON(options)

Name Type Description
dataProjection ProjectionLike (defaults to 'EPSG:4326')

Default data projection.

featureProjection ProjectionLike | undefined

Projection for features read or written by the format. Options passed to read or write methods will take precedence.

geometryName string | undefined

Geometry name to use when creating features.

extractGeometryName boolean (defaults to false)

Certain GeoJSON providers include the geometry_name field in the feature GeoJSON. If set to true the GeoJSON reader will look for that field to set the geometry name. If both this field is set to true and a geometryName is provided, the geometryName will take precedence.

Extends

Methods

readFeature(source, options){Feature} inherited

Read a feature. Only works for a single feature. Use readFeatures to read a feature collection.

Name Type Description
source ArrayBuffer | Document | Element | Object | string

Source.

options

Read options.

Name Type Description
dataProjection ProjectionLike | undefined

Projection of the data we are reading. If not provided, the projection will be derived from the data (where possible) or the dataProjection of the format is assigned (where set). If the projection can not be derived from the data and if no dataProjection is set for a format, the features will not be reprojected.

extent Extent | undefined

Tile extent in map units of the tile being read. This is only required when reading data with tile pixels as geometry units. When configured, a dataProjection with TILE_PIXELS as units and the tile's pixel extent as extent needs to be provided.

featureProjection ProjectionLike | undefined

Projection of the feature geometries created by the format reader. If not provided, features will be returned in the dataProjection.

Returns:
Feature.

readFeatures(source, options){Array<Feature>} inherited

Read all features. Works with both a single feature and a feature collection.

Name Type Description
source ArrayBuffer | Document | Element | Object | string

Source.

options

Read options.

Name Type Description
dataProjection ProjectionLike | undefined

Projection of the data we are reading. If not provided, the projection will be derived from the data (where possible) or the dataProjection of the format is assigned (where set). If the projection can not be derived from the data and if no dataProjection is set for a format, the features will not be reprojected.

extent Extent | undefined

Tile extent in map units of the tile being read. This is only required when reading data with tile pixels as geometry units. When configured, a dataProjection with TILE_PIXELS as units and the tile's pixel extent as extent needs to be provided.

featureProjection ProjectionLike | undefined

Projection of the feature geometries created by the format reader. If not provided, features will be returned in the dataProjection.

Returns:
Features.

readGeometry(source, options){Geometry} inherited

Read a geometry.

Name Type Description
source ArrayBuffer | Document | Element | Object | string

Source.

options

Read options.

Name Type Description
dataProjection ProjectionLike | undefined

Projection of the data we are reading. If not provided, the projection will be derived from the data (where possible) or the dataProjection of the format is assigned (where set). If the projection can not be derived from the data and if no dataProjection is set for a format, the features will not be reprojected.

extent Extent | undefined

Tile extent in map units of the tile being read. This is only required when reading data with tile pixels as geometry units. When configured, a dataProjection with TILE_PIXELS as units and the tile's pixel extent as extent needs to be provided.

featureProjection ProjectionLike | undefined

Projection of the feature geometries created by the format reader. If not provided, features will be returned in the dataProjection.

Returns:
Geometry.

Read the projection.

Name Type Description
source ArrayBuffer | Document | Element | Object | string

Source.

Returns:
Projection.

writeFeature(feature, options){string} inherited

Encode a feature as string.

Name Type Description
feature Feature

Feature.

options

Write options.

Name Type Description
dataProjection ProjectionLike | undefined

Projection of the data we are writing. If not provided, the dataProjection of the format is assigned (where set). If no dataProjection is set for a format, the features will be returned in the featureProjection.

featureProjection ProjectionLike | undefined

Projection of the feature geometries that will be serialized by the format writer. If not provided, geometries are assumed to be in the dataProjection if that is set; in other words, they are not transformed.

rightHanded boolean | undefined

When writing geometries, follow the right-hand rule for linear ring orientation. This means that polygons will have counter-clockwise exterior rings and clockwise interior rings. By default, coordinates are serialized as they are provided at construction. If true, the right-hand rule will be applied. If false, the left-hand rule will be applied (clockwise for exterior and counter-clockwise for interior rings). Note that not all formats support this. The GeoJSON format does use this property when writing geometries.

decimals number | undefined

Maximum number of decimal places for coordinates. Coordinates are stored internally as floats, but floating-point arithmetic can create coordinates with a large number of decimal places, not generally wanted on output. Set a number here to round coordinates. Can also be used to ensure that coordinates read in can be written back out with the same number of decimals. Default is no rounding.

Returns:
Encoded feature.

writeFeatureObject(feature, options){GeoJSONFeature}

Encode a feature as a GeoJSON Feature object.

Name Type Description
feature Feature

Feature.

options

Write options.

Name Type Description
dataProjection ProjectionLike | undefined

Projection of the data we are writing. If not provided, the dataProjection of the format is assigned (where set). If no dataProjection is set for a format, the features will be returned in the featureProjection.

featureProjection ProjectionLike | undefined

Projection of the feature geometries that will be serialized by the format writer. If not provided, geometries are assumed to be in the dataProjection if that is set; in other words, they are not transformed.

rightHanded boolean | undefined

When writing geometries, follow the right-hand rule for linear ring orientation. This means that polygons will have counter-clockwise exterior rings and clockwise interior rings. By default, coordinates are serialized as they are provided at construction. If true, the right-hand rule will be applied. If false, the left-hand rule will be applied (clockwise for exterior and counter-clockwise for interior rings). Note that not all formats support this. The GeoJSON format does use this property when writing geometries.

decimals number | undefined

Maximum number of decimal places for coordinates. Coordinates are stored internally as floats, but floating-point arithmetic can create coordinates with a large number of decimal places, not generally wanted on output. Set a number here to round coordinates. Can also be used to ensure that coordinates read in can be written back out with the same number of decimals. Default is no rounding.

Returns:
Object.

writeFeatures(features, options){string} inherited

Encode an array of features as string.

Name Type Description
features Array<Feature>

Features.

options

Write options.

Name Type Description
dataProjection ProjectionLike | undefined

Projection of the data we are writing. If not provided, the dataProjection of the format is assigned (where set). If no dataProjection is set for a format, the features will be returned in the featureProjection.

featureProjection ProjectionLike | undefined

Projection of the feature geometries that will be serialized by the format writer. If not provided, geometries are assumed to be in the dataProjection if that is set; in other words, they are not transformed.

rightHanded boolean | undefined

When writing geometries, follow the right-hand rule for linear ring orientation. This means that polygons will have counter-clockwise exterior rings and clockwise interior rings. By default, coordinates are serialized as they are provided at construction. If true, the right-hand rule will be applied. If false, the left-hand rule will be applied (clockwise for exterior and counter-clockwise for interior rings). Note that not all formats support this. The GeoJSON format does use this property when writing geometries.

decimals number | undefined

Maximum number of decimal places for coordinates. Coordinates are stored internally as floats, but floating-point arithmetic can create coordinates with a large number of decimal places, not generally wanted on output. Set a number here to round coordinates. Can also be used to ensure that coordinates read in can be written back out with the same number of decimals. Default is no rounding.

Returns:
Encoded features.

writeFeaturesObject(features, options){GeoJSONFeatureCollection}

Encode an array of features as a GeoJSON object.

Name Type Description
features Array<Feature>

Features.

options

Write options.

Name Type Description
dataProjection ProjectionLike | undefined

Projection of the data we are writing. If not provided, the dataProjection of the format is assigned (where set). If no dataProjection is set for a format, the features will be returned in the featureProjection.

featureProjection ProjectionLike | undefined

Projection of the feature geometries that will be serialized by the format writer. If not provided, geometries are assumed to be in the dataProjection if that is set; in other words, they are not transformed.

rightHanded boolean | undefined

When writing geometries, follow the right-hand rule for linear ring orientation. This means that polygons will have counter-clockwise exterior rings and clockwise interior rings. By default, coordinates are serialized as they are provided at construction. If true, the right-hand rule will be applied. If false, the left-hand rule will be applied (clockwise for exterior and counter-clockwise for interior rings). Note that not all formats support this. The GeoJSON format does use this property when writing geometries.

decimals number | undefined

Maximum number of decimal places for coordinates. Coordinates are stored internally as floats, but floating-point arithmetic can create coordinates with a large number of decimal places, not generally wanted on output. Set a number here to round coordinates. Can also be used to ensure that coordinates read in can be written back out with the same number of decimals. Default is no rounding.

Returns:
GeoJSON Object.

writeGeometry(geometry, options){string} inherited

Encode a geometry as string.

Name Type Description
geometry Geometry

Geometry.

options

Write options.

Name Type Description
dataProjection ProjectionLike | undefined

Projection of the data we are writing. If not provided, the dataProjection of the format is assigned (where set). If no dataProjection is set for a format, the features will be returned in the featureProjection.

featureProjection ProjectionLike | undefined

Projection of the feature geometries that will be serialized by the format writer. If not provided, geometries are assumed to be in the dataProjection if that is set; in other words, they are not transformed.

rightHanded boolean | undefined

When writing geometries, follow the right-hand rule for linear ring orientation. This means that polygons will have counter-clockwise exterior rings and clockwise interior rings. By default, coordinates are serialized as they are provided at construction. If true, the right-hand rule will be applied. If false, the left-hand rule will be applied (clockwise for exterior and counter-clockwise for interior rings). Note that not all formats support this. The GeoJSON format does use this property when writing geometries.

decimals number | undefined

Maximum number of decimal places for coordinates. Coordinates are stored internally as floats, but floating-point arithmetic can create coordinates with a large number of decimal places, not generally wanted on output. Set a number here to round coordinates. Can also be used to ensure that coordinates read in can be written back out with the same number of decimals. Default is no rounding.

Returns:
Encoded geometry.

writeGeometryObject(geometry, options){GeoJSONGeometry | GeoJSONGeometryCollection}

Encode a geometry as a GeoJSON object.

Name Type Description
geometry Geometry

Geometry.

options

Write options.

Name Type Description
dataProjection ProjectionLike | undefined

Projection of the data we are writing. If not provided, the dataProjection of the format is assigned (where set). If no dataProjection is set for a format, the features will be returned in the featureProjection.

featureProjection ProjectionLike | undefined

Projection of the feature geometries that will be serialized by the format writer. If not provided, geometries are assumed to be in the dataProjection if that is set; in other words, they are not transformed.

rightHanded boolean | undefined

When writing geometries, follow the right-hand rule for linear ring orientation. This means that polygons will have counter-clockwise exterior rings and clockwise interior rings. By default, coordinates are serialized as they are provided at construction. If true, the right-hand rule will be applied. If false, the left-hand rule will be applied (clockwise for exterior and counter-clockwise for interior rings). Note that not all formats support this. The GeoJSON format does use this property when writing geometries.

decimals number | undefined

Maximum number of decimal places for coordinates. Coordinates are stored internally as floats, but floating-point arithmetic can create coordinates with a large number of decimal places, not generally wanted on output. Set a number here to round coordinates. Can also be used to ensure that coordinates read in can be written back out with the same number of decimals. Default is no rounding.

Returns:
Object.