Copyright © 2015 Open Geospatial Consortium.
31
Abstract DefaultCRSurn:ogc:def:crs:EPSG::900913DefaultCRS
ows:WGS84BoundingBox ows:LowerCorner-124.40958558399815
32.50005761536461ows:LowerCorner ows:UpperCorner-114.58848453257575
43.33627233179173ows:UpperCorner ows:WGS84BoundingBox
FeatureType ...
Should be converted into:
{ Name: NHDPlusFlowlines:FeatureTypeList,
FeatureType: [ {
Name: NHDPlusFlowlines:PlusFlowlineVAA_NHDPlus18, Title: PlusFlowlineVAA,
Abstract: null, DefaultCRS: urn:ogc:def:crs:EPSG::900913,
bbox: [-124.40958558399815 32.50005761536461, -114.58848453257575, 43.33627233179173]
} }
The corresponding context could be: Using the following context:
context: {
wfs: http:www.opengis.netwfs2.5, ows: http:www.opengis.netows2.0,
geojson: http:ld.geojson.orgvocab, Name: id,
Title: ows:Title, Abstract: ows:Abstact,
DefaultCRS: wfs:DefaultCRS, bbox: geojson:bbox,
}
Recommendation 11: Include in the JSON best practice that if a fragment of a XML document contains a geospatial object then when converting to JSON, consider using the GeoJSON equivalent
type. Target: OWS.Common
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Copyright © 2015 Open Geospatial Consortium.
6.2 Derive JSON from UML
Deriving JSON form UML is out of scope of this Engineering Report. The Engineering Report elaborated in the Testbed 9 OGC 12-093 “OWS-9: UML-to-GML-Application-
Schema UGAS Conversion Engineering Report”, elaborates on how to derive JSON encodings from UML automatically.
7 Discussion about GeoJSON
7.1 JSON Schema for GeoJSON
In the same way that a GML instance can be described by a GML application schema XSD file a GeoJSON file can be described by a JSON Schema. There are two
approaches for this:
A generic JSON schema describing any GeoJSON file. A specific JSON schema describing a particular GeoJSON file of a particular
feature type.
7.1.1 Generic GeoJSON validation
https:github.comfgesample-json-schemastreemastergeojson provides an attempt to generate a GeoJSON generic JSON schema. This can be useful to validate that a JSON
file is in fact a GeoJSON file but does not provide the “GML application schema” functionality.
We have done a similar exercise during the process of defining a JSON Schema for OWS Context as seen later.
{ schema: http:json-schema.orgdraft-04schema,
title: GeoJSON schema, type: object,
required: [ type ], properties: {
type: { enum: [ FeatureCollection ] }, id : { type: string, format: uri },
bbox: { type: array,
items: { type: array,
minItems: 4, items : { type: number }
} },
features : {
Copyright © 2015 Open Geospatial Consortium.
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type: array, items: {
type: object, required: [ type, properties],
properties: { type: { enum: [ Feature ] },
geometry: { ref: definitionsgeometry }, properties: { type: object }
} }
} },
definitions: { geometry: {
title: geometry, type: object,
oneOf: [{ properties: {
type: { enum: [ Point] }, coordinates: {
type: array, minItems: 2,
items: { type: number} }
} },
{ properties: {
type: { enum: [ LineString, Multipoint]}, coordinates: {
type: array, minItems: 2,
items: { type: array,
minItems: 2, items : { type: number }
} }
} },
{ properties: {
type: { enum: [ Polygon, MultiLineString]},
coordinates: { type: array,
items: { type: array,
minItems: 2, items: {
type: array,
