The border between Geographic information Systems (GIS) and Computer Added Design (CAD) is fading.Software for CAD was primarily designed to deal with large-scale models (but relatively small in size), without maintenance of attributes and geographic coordinates systems.In contacts, GIS was able to manage small-scale models (but very large in size), maintain attributes and a variety of different geographic coordinate systems.As CAD has developed towards Architecture Engineering and Construction (AEC) solutions, nowadays large-scale geo-information is a topic of interest for both CAD/AEC and GIS users.For many years, AEC designers have been frequently confronted with the request to provide the means to link small scale mapping to newly designed construction models.GIS users more and more often use tools available in AEC systems to reconstruct and edit large-scale, realistic 3D models.

Despite the progress in bridging GIS and Systems for AEC, many fundamental issues have still to be addressed.The aim of AEC engineers is no longer designing in a local environment.The local environments are now part of a wider world, where projected coordinates are needed.Since the same information is reused and updated, a system is needed to maintain the integrity and consistency of geo-data.How and where to maintain topology? How and where to maintain attribute information? How to maintain geographic coordinates systems.

3D GIS face even more challenges.AEC software provides all kinds of primitives to design and visualize models, however these primitives are not supported in the GIS world.How to use AEC primitives (e.g.3D parametric primitives, splines) in an OpenGIS compliant environment? How can OpenGIS primitives be used in combination with AEC functionalities (textures, shading etc.) to represent a model close to reality? While 2D GIS have quite advanced tools to edit/update geometry, 3D GIS users are only provided with visualization/navigation environments.AEC designers may become major providers of large-scale 3D geo-data with the ability to edit/update in 3D.

We are please that Directions Magazine is helping to advanced the discussion of this topic.A book will be published as a result of this ten-part series on CAD-GIS integration. This book focuses on fundamental aspects of large-scale 3D geo-information taking into account the latest developments in 3D GIS and AEC Systems.It will outline the current problems and recommends areas for research.

Other installments published to date in this series:
Introduction: Large-scale 3D data integration - An Introduction to the Challenges for CAD and GIS Integration
Chapter 1: Bridging the Worlds of CAD and GIS
Chapter 2: 3D Data Acquisition and Object Reconstruction for AEC/CAD
In addition to the articles themselves, numerous readers have also posted comments on them (found at the bottom of each article).