Esri JSON

A .NET Standard implementation of the Esri JSON geometry/feature format used by the ArcGIS REST API. Read and write Esri JSON, and convert to/from the library's Geometry<T> and FeatureSet<Point> types.

Supported capabilities

Capability	Supported
Read	Yes — EsriJsonGeometry.Parse, EsriJsonFeatureSet.Parse / Load
Write	Yes — EsriJsonGeometry.ToString, EsriJsonFeatureSet.Save
Z / M coordinates	Yes on geometry (hasZ / hasM); features flatten to X/Y
Envelope geometry	No — esriGeometryEnvelope is in the type enum but conversion throws

Geometry types: point (esriGeometryPoint), multipoint (esriGeometryMultipoint), polyline (esriGeometryPolyline), polygon (esriGeometryPolygon). Feature sets carry fields, attributes, and spatial reference (wkid / latestWkid). A geometry can also be written as WKT via AsWkt().

Usage

Types live in IRI.Maptor.Core.Spatial.IO.EsriJson; the Geometry<T> extension lives in IRI.Maptor.Extensions.

Feature sets

using IRI.Maptor.Core.Spatial.IO.EsriJson;
using IRI.Maptor.Core.Spatial.Primitives;

// Read
EsriJsonFeatureSet? esri = EsriJsonFeatureSet.Parse(jsonString);   // from a string
EsriJsonFeatureSet? fromFile = await EsriJsonFeatureSet.Load("features.json");

// Convert to the library type
FeatureSet<Point> featureSet = esri!.AsFeatureSet();

// Write
EsriJsonFeatureSet back = EsriJsonFeatureSet.Parse(featureSet)!;   // from a FeatureSet<Point>
await back.Save("out.json", indented: true);

Geometry

using IRI.Maptor.Core.Spatial.IO.EsriJson;
using IRI.Maptor.Extensions;
using IRI.Maptor.Core.Spatial.Primitives;

// Esri JSON string → EsriJsonGeometry → library geometry
EsriJsonGeometry? esriGeom = EsriJsonGeometry.Parse(geometryJson);
IGeometry geometry = esriGeom!.Parse(srid: 4326);

// library geometry → EsriJsonGeometry → Esri JSON string
var polygon = Geometry<Point>.Create(points, GeometryType.Polygon, 4326);
EsriJsonGeometry esri = polygon.AsEsriJsonGeometry();
string json = esri.ToString();   // Esri JSON
string wkt  = esri.AsWkt();       // WKT

Format details

Aspect	Esri JSON in Maptor
Coordinate system	Esri JSON carries an explicit spatialReference (wkid / latestWkid) and supports any CRS. Maptor preserves it; SRID resolves as latestWkid ?? wkid. EsriJsonFeature.AsFeature(srid, targetSrs) can optionally project to another SRS. On write from a FeatureSet<Point>, LatestWkid is set from the feature set's SRID.
Z / M	The geometry model has hasZ / hasM; EsriJsonGeometry.Parse(srid) returns Geometry<PointZM/PointZ/Point> accordingly. Reading a full feature via AsFeature flattens to Geometry<Point> (X/Y).
Polygon rings	Esri's convention is the opposite of GeoJSON — exterior rings clockwise, holes counterclockwise, closed (first = last). The writer reverses Geometry<Point> winding to match Esri's order.
Serialization	System.Text.Json (camelCase). Deserialize: EsriJsonGeometry.Parse, EsriJsonFeatureSet.Parse / Load. Serialize: EsriJsonGeometry.ToString, EsriJsonFeatureSet.Save.
Specification	ArcGIS REST API — Geometry objects

Limitations

• Polygon Rings and polyline Paths follow the Esri convention; multiple rings/paths become MultiPolygon/MultiLineString.
• esriGeometryEnvelope is defined in the type enum but is not converted (it throws).
• EsriJsonFeatureSet.Save(...) writes to a file; there is no method that returns the full feature-set JSON as a string. A single geometry's Esri JSON is available via EsriJsonGeometry.ToString().

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