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Storing the 3D topography of the Netherlands wi...

Hugo Ledoux
October 02, 2019

Storing the 3D topography of the Netherlands with CityJSON

Hugo Ledoux

October 02, 2019
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  1. Storing the 3D topography of the Netherlands with CityJSON Hugo

    Ledoux Open Geodag Amersfoort, the Netherlands 2019-10-02
  2. 2

  3. 4 international standard (from OGC) for representing and storing 3D

    city models IMGeo 3D: stored since ~2012 with a CityGML ADE
  4. BUT

  5. CityGML-ADE files are very complex and HUGE 10 ➡ virtually

    no software support ➡ little use of the resulting files in practice ➡ no parsers in JavaScript (thus no web support) ➡ did I mention files are HUGE and complex?
  6. CityGML-ADE files are very complex and HUGE 11 ➡ virtually

    no software support ➡ little use of the resulting files in practice ➡ no parsers in JavaScript (thus no web support) ➡ did I mention files are HUGE? In brief • we have all the IMGeo 3D files (CityGML) • no one uses them
  7. 12

  8. 13 1. JSON encoding for 3D city models 2. designed

    with programmers in mind 3. ready for the web 4. 6X more compact then CityGML 5. Extensions can be easily defined and used
  9. Same information as CityGML, but in JSON format 14 {

    "type": “CityJSON", "version": “1.0”, "metadata": { "referenceSystem": "urn:ogc:def:crs:EPSG::7415", }, "CityObjects": { "id-1": { "type": "Building", "attributes": { "measuredHeight": 22.3, "roofType": "gable", "owner": “Elvis Presley" }, "geometry": [ { "type": "MultiSurface", "boundaries": [ [[0, 3, 2, 1]], [[4, 5, 6, 7]], [[0, 1, 5, 4]] ] } ] } }, "vertices": [ [23.1, 2321.2, 11.0], [111.1, 321.1, 12.0], ... ], "appearance": { "materials": [], "textures":[], "vertices-texture": [] } } human readable all programming language support JSON “natively”
  10. Compression example: Zürich LoD2 buildings 17 CityGML = 3.0GB (but

    1GB of spaces/CRs/tabs!) CityJSON = 292MB Compression == 7.1X
  11. CityJSON with an Extensions 20 { "type": "CityJSON", "version": "1.0",

    "extensions": { "Noise": { "url" : "https://someurl.org/noise.json", "version": "1.0" } }, "CityObjects": { "1234": { "type": "Building", "geometry": [ { "type": "Solid", "lod": 2, "boundaries": [ [ [[0, 3, 2, 1]], …, [[3, 0, 4, 7]] ] ] } ], "attributes": { "roofType": "pointy", "class": "22", "+noise-buildingReflectionCorrection": { "value": 4.123, "uom": “dB" }, "+noise-buildingLNightMax": { "value": 43.123, "uom": "dB" } } }, "thesegment_1": { "type": "+NoiseCityFurnitureSegment", "toplevel": false, "geometry": [ { "type": "MultiLineString", "lod": 0, "boundaries": [ [2, 3, 5], [7, 5, 12] ] } ], "attributes": { "reflectionCorrection": { "value": 4.123, "uom": "dB" } }, "parents": ["a_noisy_bench"] }, "thesegment_2": { "type": "+NoiseCityFurnitureSegment", "toplevel": false, "geometry": [ { "type": "MultiLineString", "lod": 0, "boundaries": [ [2, 3, 5], [7, 2, 12] ] } ], "attributes": { "reflectionCorrection": { "value": 2.666, "uom": "dB"
  12. CityJSON with an Extensions 21 { "type": "CityJSON", "version": "1.0",

    "extensions": { "Noise": { "url" : "https://someurl.org/noise.json", "version": "1.0" } }, "CityObjects": { "1234": { "type": "Building", "geometry": [ { "type": "Solid", "lod": 2, "boundaries": [ [ [[0, 3, 2, 1]], …, [[3, 0, 4, 7]] ] ] } ], "attributes": { "roofType": "pointy", "class": "22", "+noise-buildingReflectionCorrection": { "value": 4.123, "uom": “dB" }, "+noise-buildingLNightMax": { "value": 43.123, "uom": "dB" } } }, "thesegment_1": { "type": "+NoiseCityFurnitureSegment", "toplevel": false, "geometry": [ { "type": "MultiLineString", "lod": 0, "boundaries": [ [2, 3, 5], [7, 5, 12] ] } ], "attributes": { "reflectionCorrection": { "value": 4.123, "uom": "dB" } }, "parents": ["a_noisy_bench"] }, "thesegment_2": { "type": "+NoiseCityFurnitureSegment", "toplevel": false, "geometry": [ { "type": "MultiLineString", "lod": 0, "boundaries": [ [2, 3, 5], [7, 2, 12] ] } ], "attributes": { "reflectionCorrection": { "value": 2.666, "uom": "dB"
  13. For IMGeo? We started a pilot with Geonovum 22 {

    "type": "CityJSON_Extension", ʼname": "NL3D", "uri": "https://github.com/hugoledoux/nl3d/blob/master/schemas/extensions/nl_3d.json", "version": "0.1", "description": "NL3D data model as a CityJSON Extension.", “extraCityObjects": { "+Pand": { "allOf": [ { "$ref": "../cityobjects.schema.json#/_AbstractCityObject"}, { "properties": { "type": { "enum": ["+Pand"] }, "toplevel": {"type": "boolean"}, "@context": { "type": "string", "format": "uri-reference" }, "attributes": { "properties": { "yearOfConstruction": { "type": "integer" }, "gebouwnummer": { "type": "string" }, "statusOmschr": { "type": "string" }, "hoogste_bouwlaag": { "type": "integer" }, "hoogste_bouwlaag": { "type": "integer" }, "laagste_bouwlaag": { "type": "integer" }, "aantalBouwlagen": { "type": "integer" } } }, "geometry": { "type": "array", "items": { "oneOf": [ {"$ref": "../geomprimitives.schema.json#/Solid"}, {"$ref": "../geomprimitives.schema.json#/CompositeSolid"}, {"$ref": "../geomprimitives.schema.json#/MultiSurface"}
  14. 23