i scope timedependentvariables

i-SCOPE - interoperable Smart City services through an Open Platform for urban Ecosystems

CityGML - Time Dependent Variables

Debbie Wilson – Snowflake Software Peter Parslow - Ordnance Survey

Volker Kraut - MOSS

interoperable Smart City services through an Open Platform for urban Ecosystems


Overview

• What is a time-dependent variable?• Real-world objects may have dynamic properties that varying over time• Some phenomenon such as temperature or noise are highly dynamic

over space and time

• A time-dependent variable defines property value(s) for a specific reference time

• Requirements:1. Must be generic and can be applied to any City Object2. Support both simple and complex variables:

• Single scalar value (i.e. indicator or measure)• Time-series• Composite scalar values (e.g. min, max, mean)

3. Provide metadata about the time dependent variable• How was the time-dependent variable derived?


Time Dependent Variable• Proposed model:

• Generic TimeDependentVariable <<FeatureType>> extends from Abstract City Object

• Follows similar modelling pattern to ISO 19156 – Observations and Measurements

Time-Dependent Variable

ProcessProperty Type

ValueTime


Requirements• Two Requirements:

1. Append properties to a City Object that relates to a specific reference time

2. 3D modelling of dynamic phenomenon which vary over space and time that do not relate to a specific City Object:• Thematic Heat Map or • Thematic Contour Map


TimeDependentVariable

class Context Diagram: Time-Dependent Variables

«metaclass»General Feature Model::

GF_PropertyType{root}

+ memberName :LocalName+ definition :CharacterString

«FeatureTyp...observation::OM_Process

«type»Records and

Class Metadata::Any

{root}

«FeatureType»TimeDependentVariable

+ referenceTime :TM_Object+ validTime :TM_Period [0..1]

«Union»Variable

«dataType»CityGML_Core::

AbstractGenericAttribute

+ name :CharacterString

«DataType»TimeDpendentVariable - TimeSeries::TimeSeries

Phenomenon

+property

1

Process

+procedure

0..1

Range

+variable 1

1

1 1NOTE: v0.2 change to “constrain” the variable type to either:• CityGML generic attribute• TimeSeries• Any – which shall be

substituted for complex types defined within an ADE


Extending AbstractCityObject• Two Options

1. Extend AbstractCityObject to add a timeDependentVariable as a new property class CityGML ADE: Extending Abstract CityObject

«FeatureType»TimeDependentVariable::TimeDependentVariable



«type»Records and

Class Metadata::Any

{root}

«ADEElement»TimeDependentVariable::AbstractCityObject

+ timeDependentVariable :TimeDependentVariable [0..*]

«featureType»CityGML_Core::AbstractCityObject

+ creationDate :Date [0..1]+ terminationDate :Date [0..1]+ externalReference :ExternalReference [0..*]+ relativeToTerrain :RelativeToTerrain [0..1]+ relativeToWater :RelativeToWater [0..1]+ genericAttribute :AbstractGenericAttribute [0..*]




Phenomenon

+property 1

+generalizesTo 0..*

Process

+procedure

0..1

Range

+variable 1


Extending AbstractCityObject• Two Options

1. Extend AbstractCityObject to add a timeDependentVariable as a new property

2. Extend AbstractGenericAttribute to add TimeDependentVariable as a new generic attribute

class Option 3: Extending GenericAttribute


UriAttribute

+ value :URI

«dataType»CityGML_Core::StringAttribute

+ value :CharacterString


MeasureAttribute

+ value :Measure


IntAttribute

+ value :Integer


DateAttribute

+ value :Date

«dataType»CityGML_Core::DoubleAttribute

+ value :Number




«DataType»TimeDependentVariable::TimeDependentAttribute

+ value :TimeDependentVariable


Creating a Thematic Heat Map City Object• Two Options

1. Model the TimeDependentVariable class as a new City Object, then create a ThematicHeatMap that extends TimeDependentVariable


Time Dependent Variable

TimeDependentVariable Modelled as a City Object

class Context Diagram: Time-Dependent Variables







«type»Records and

Class Metadata::Any

{root}

«FeatureType»TimeDependentVariable


«Union»Variable




«DataType»TimeDpendentVariable - TimeSeries::TimeSeries

+generalizesTo 0..*

Phenomenon

+property

1

Process

+procedure

0..1

Range

+variable 1

1

1 1

Option 1


class Context Diagram: Noise Heat Map

«FeatureType»ThematicHeatMapSurface

+ lod0Surface :GM_MultiSurface [0..1]+ lod1Surface :GM_MultiSurface [0..1]

AbstractCityObject

«FeatureType»TimeDependentVariable::TimeDependentVariable


«DataType»NoiseExposureDataRecord

+ minLAeq :Measure+ maxLAeq :Measure+ meanLAeq :Measure

«FeatureType»observation::OM_Process

«FeatureType»SurfaceNoiseMap

constraints{/* variable must be a NoiseExposureDataRecord */inv: self.variable.oclIsKindOf(NoiseExposureDataRecord)}

«FeatureType»RasterThematicHeatMap

constraints{/* variable must be a GM_RectifiedGridCoverage*/inv: self.variable.oclIsKindOf(GM_RectifiedGridCoverage)}



Phenomenon

+property 1

+variable

1

Process

+procedure 0..1

Creating a Thematic Heat Map City ObjectOption 1

Can then extend the TimeDependentVariable feature to generate ThematicHeatMap

features and can specify ‘profile’ the variable type


Example – Option 1 – Creating a Thematic Heat Map


Creating a Thematic Heat Map City Object• Option 2

• Model the ThematicHeatMap as a new CityObject that uses the a generic time dependent variable attribute class Noise Map: Generic Attribute

«FeatureType»SurfaceNoiseMap_GenericAttribute


«ADEElement»TimeDependentVariable::AbstractCityObject

+ timeDependentVariable :TimeDependentVariable [0..*]



+generalizesTo 0..*

class Noise Map: Generic Attribute

«FeatureType»SurfaceNoiseMap_GenericAttribute




+generalizesTo 0..*

Or


Conclusions

i scope timedependentvariables

Technology

generic timedependentvariable

date datatype citygml

measure datatype citygml

uri datatype citygml

integer datatype citygml

number datatype citygml

variable type

new city object