This document discusses integrating CityGML 3D city model data into ArcGIS systems using FME. It provides an overview of CityGML and Indexed 3D Scene Layers standards, challenges in converting between the formats like preserving semantics and representations, and workflows for importing CityGML into ArcGIS Pro geodatabases and scene layer packages using FME tools. It also describes the ArcGIS CityGML toolbox for standardizing CityGML import into ArcGIS and a future vision of more integrated BIM and GIS data workflows.

1. CityGML Integration into the
ArcGIS System

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User
Conference
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Christian Dahmen
Teamlead
Data Integration Product Services
con terra GmbH
Long-time FME Enthusiast and CityGML
Evangelist
Co-Presenter
Andreas Lippold | Principal Product Manager –
3D, AEC, Smart Cities (Europe)

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Open Standards
Matter

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Open Standards are an
important mean to share
spatial data and allow
users to collaborate.
Nevertheless, without
FME one would be lost!

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Agenda
● 3D Open Standards
● Semantic Data Transformation
● ETL workflows to integrate CityGML data
into the ArcGIS System

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3D Open Standards

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3D (Open) Standards
Categories / Purpose
● Exchange Formats
● Transmission
● Visualization

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3D (Open) Standards

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Why CityGML and I3S?
CityGML
• OGC Standard for 3D City Models
• In Germany, Europe, Asia and
worldwide
• Rich semantics
Indexed 3D Scene Layers (I3S)
• OGC Standard for 3D Streaming
• Fast and modern approach
• Supported across the ArcGIS
System
Source: CityGML 2.0 Spec

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CityGML | Basics
• OGC Standard (https://www.opengeospatial.org/standards/citygml)
• Data model for storing and exchanging 3D City Models
• Modeling of all relevant parts of a virtual city according to
• Semantics
• Geometry (and Topology)
• Appearance
• Objects know WHAT they are and WHERE they are
• Required for sophisticated queries, simulations
and analysis
• Level of Detail (LoD) concept
Source: Biljecki2016

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CityGML | Organized in Modules
Building Module
CityFurniture Module
Relief Module
Transportation
Module
Vegetation Module WaterBody Module
Bridge Module
Tunnel Module
Source: KIT Karlsruhe

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Indexed 3D Scene Layers (I3S) | Basics
• OGC Community Standard (https://www.opengeospatial.org/standards/i3s)
• Open standard for storage and transmission of large, heterogeneous 3D
geospatial data sets
• Cloud, Web and Mobile friendly based on JSON, REST and modern web
standards
• Support 3D geospatial content, various coordinate systems along with a rich
set of layer types

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Indexed 3D Scene Layers (I3S) | Layer types
• Points
• 3D Objects
• Integrated Meshes
• Point Clouds
• (BIM) Building
Source: https://developers.arcgis.com/

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Semantic Data Transformation

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How to convert between?
CityGML
Indexed
3D Scene
Layers
(I3S)
Data Conversion
Semantic
Data
Transformation

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Known Challenges
• Format conversion (GML vs. JSON/ binary/ folder)
• Coordinate Reference Systems
• Filter by object type
• … easy to solve
with FME!

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Special Challenge #1 - Semantics
• How to (best) preserve rich semantics?
• e.g. Building and BuildingParts -> results in one single object vs. many objects
• Helpful transformers: Aggregator, GeometryExtractor, GeometryFilter,
GeometryPartExtractor, GeometryReplacer
Source: https://wiki.quality.sig3d.de/ Source: https://wiki.quality.sig3d.de/

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Special Challenge #2 - Multiple Representations
• One to many representations in CityGML
• Select the ‘right’ object representation
• Helpful transformers: TestFilter, StatisticsCalculator,
DuplicateFilter
LoD 1 LoD 2 LoD 3
Source: https://wiki.quality.sig3d.de/

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Challenge #3
• Handle ‘No Features’
• Missing Features / Missing Parts result in unexpected results
?

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ETL workflows to integrate CityGML data into the
ArcGIS System

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Data Preparation Workflow(s)
CityGML file(s)
Geodatabase
Scene Layer Packages
(I3S)
FME
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FME
ArcGIS Pro
AUTOMATE (FME+ Pro + ArcGIS REST API)

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CityGML toolset for ArcGIS Pro
• Best practice appraoch to import CityGML into the ArcGIS System
based on FME / Data Interoperability Extension
• Support for Buildings, CityFurniture, LandUse,
and Vegetation
• ArcGIS Pro Toolbox (v2.9 / 3.x)
• CityGML 1.0 und 2.0
• Ready to use
• Customizable
• Includes documentation

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Get the CityGML tools
Download the CityGML Toolbox (v 1.3) right now and
right here:

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Outlook and Vision
● Esri plans to provide more CityGML tools
● Add more thematic Modules driven by demand
and user feedback
● Future: Support for CityGML 3.0
● Vision: Integrated workflow for GIS and
BIM-related data

25. Thank You!
c.dahmen@conterra.de and alippold@esri.com

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