metadata.py

#-- generate full metadata for hdb3d-data
#-- metadata can be written to the parent file or separately

import json
import uuid
import os
import time
from datetime import date, datetime

def main():
    #specify if you want the metadata in the file or separately with inFile = True or inFile = False
    inFile = True
    in_cm_name = '_data/hdb.json'
    with open(in_cm_name, 'r+') as cm:
        json_cm = json.load(cm)
        full_metadata = generate_metadata(json_cm, cm, in_cm_name)
        if inFile:
            json_cm['metadata'] = full_metadata
            cm.seek(0)
            cm.write(json.dumps(json_cm, indent=2))
            cm.truncate()
            print("Full metadata written to file")
        else:
            #check if parent file already has unique id, adds it if missing
            if not json_cm['metadata'].get("citymodelIdentifier"):
                json_cm['metadata']["citymodelIdentifier"] = full_metadata["citymodelIdentifier"]
                cm.seek(0)
                cm.write(json.dumps(json_cm, indent=2))
                cm.truncate()
            md_file = os.path.basename(cm.name).split(".")[0] + '_metadata.json'
            with open('_data/'+md_file, 'w') as md:
                md.write(json.dumps(full_metadata[0], indent=2))
            print("Full metadata written to separate file")

def generate_metadata(citymodel,cm_file,cm_file_name):
    if not citymodel["metadata"].get("citymodelIdentifier"):
        unique_id = str(uuid.uuid4())
    else:
        unique_id = citymodel["metadata"]["citymodelIdentifier"]
    metadata = {
        "citymodelIdentifier": unique_id,
        "datasetTitle": "3D city model of public housing (HDB) buildings in Singapore",
        "datasetReferenceDate": datetime.fromtimestamp(os.path.getmtime(cm_file_name)).strftime('%Y-%m-%d %H:%M:%S'),
        "geographicLocation": "Singapore, Republic of Singapore",
        "datasetLanguage": "English",
        "datasetCharacterSet": "UTF-8",
        "datasetTopicCategory": "geoscientificInformation",
        "distributionFormatVersion": citymodel["version"],
        "referenceSystem": "urn:ogc:def:crs:EPSG::3414",
        "spatialRepresentationType": "vector",
        "onlineResource": "https://github.com/ualsg/hdb3d-data",
        "fileIdentifier": os.path.basename(cm_file.name),
        "geographicalExtent": [
            11474.615816611371,
            28054.808157231186,
            0,
            45326.44585339671,
            48758.78176700817,
            141.3
        ],
        "datasetPointOfContact": {
            "contactName": "NUS Urban Analytics Lab, National University of Singapore",
            "emailAddress": "filip@nus.edu.sg",
            "contactType": "organization",
            "website": "https://ual.sg/"
            },
        "metadataStandard": "ISO 19115 - Geographic Information - Metadata",
        "metadataStandardVersion": "ISO 19115:2014(E)",
        "metadataLanguage": "English",
        "metadataCharacterSet": "UTF-8",
        "metadataDateStamp": str(date.today()),
        "metadataPointOfContact":{
            "contactName": "Anna Labetski",
            "emailAddress": "a.labetski@tudelft.nl",
            "contactType": "processor",
            "website": "https://3d.bk.tudelft.nl/alabetski/"
            },
        "lineage":[
            {
                "thematicModels":["Building"],
                "source":[{
                    "description": "2D building footprints from OpenStreetMap",
                    "sourceCitation": "https://www.openstreetmap.org/#map=12/1.3649/103.8229",
                    "sourceReferenceSystem": "urn:ogc:def:crs:EPSG::4326"
                    },
                    {
                    "description": "HDB Property Information",
                    "sourceCitation": "https://data.gov.sg/dataset/hdb-property-information",
                    }
                ],
                "processStep":{
                    "description": "Buildings extruded to LoD1.2 based on number of stories.",
                    "processor":{
                        "contactName": "NUS Urban Analytics Lab, National University of Singapore",
                        "emailAddress": "filip@nus.edu.sg",
                        "contactType": "organization",
                        "website": "https://ual.sg/"
                        },
                    "stepDateTime": datetime.fromtimestamp(os.path.getmtime(cm_file_name)).strftime('%Y-%m-%d %H:%M:%S'),
                    "reference": "https://github.com/ualsg/hdb3d-code"
                }
            }],
        "temporalExtent":{
            "startDate": "2019-07-05",
            "endDate": "2019-07-18",
        },
        "abstract": "A 3D city model of all public housing (HDB) buildings in Singapore, generated by conflating different open datasets. Public housing accommodates the predominant majority of Singapore’s population, so the dataset covers most of the nation’s residential buildings. Generated using extrusion, with the number of storeys of each block utilised as a proxy for the height. Cities around the world are increasingly releasing their 3D city models as open data. Researchers and practitioners in different disciplines are using 3D geoinformation to carry out a variety of spatial analyses. This model is openly available, hopefully benefiting researchers who previously did not have access to such data.",
        "specificUsage": "Openly available 3D city model of Singapore",
        "keywords":[
            "cityJSON",
            "3D",
            "city model",
            "public housing",
            "Singapore",
            "buildings"
        ],
        "constraints":{
            "legalConstraints":"licenceUnrestricted",
            "securityConstraints":"unclassified",
            "userNote":"open access"
        },
        "thematicModels":[
            "Building"
        ],
        "textures": "absent",
        "materials": "absent",
        "presentLoDs":{
            "1.2": len(citymodel["CityObjects"])
        },
        "cityfeatureMetadata":{
            #Right now only Building but can add other modules in the future
            "Building":{
                "uniqueFeatureCount": len(citymodel["CityObjects"]),
                "aggregateFeatureCount": len(citymodel["CityObjects"]),
                "presentLoDs":{
                    "1.2": len(citymodel["CityObjects"])
                }
                #TO DO: BuildingParts and BuildingInstallations
            }
        }
    }
    return metadata

if __name__ == '__main__':
    main()