Geographic Information Systems GIS 3D

3D Modeling Definition ► 3D Modeling is the process of developing a mathematical representation of a three- dimensional object ► Any method of representing something in 3 dimensions can be considered 3D Modeling

Advantages of 3D Modeling ► Visual – 3D Models can be eye-catching. Humans are good at processing visual information ► Intuitive – Humans live in a 3D world. 3D representations are compatible with the human experience ► Immersive – Viewers can interact and engage with 3D models

Advantages of 3D.. ► 3D models can represent aspects of the environment that 2D neglects ► Consider that much of the developed world lives in a vertically constructed world ► 2D fails to consider this vertical dimension in which people are living

Disadvantages of 3D Modeling ► Difficult – 3D modeling software packages require considerable expertise ► Data Intensive – 3D models can be huge. 3D renders can require supercomputers to process ► Time Intensive – Added realism requires added manpower. Modeling details can be an extremely time intensive process

2.5D versus true 3D ► There is often a distinction made between 2.5D and 3D ► In 2.5D, for a given pair of x and y, there is only one z. In 3D, for a given pair of x and y, there are more than one z ► 2.5D objects appear 3D, but aren't true 3D. Examples are TINs and draped DEMs. Google Street View is another example

Building Extraction ► Much remote sensing research has been devoted to automated construction of 3D buildings ► Typically, such research integrates LIDAR and satellite or aerial imagery to capture buildings ► LIDAR captures building height

Building Extraction Forstner 1999

Building Extraction Applications ► One application of building extraction is population estimation. If one can accurately capture the size of buildings, one can estimate the population living or working there with reasonable accuracy

Building Extraction Applications ► Quick extraction of buildings is extremely useful for urban planning ► Quick extraction of buildings may be applied to disaster settings such as the earthquake in Japan

Emergency Management ► In emergencies (e.g. 9/11), it is critical to have accurate building plans. 3D models can improve the response time of emergency personnel

Time Geography ► Time geography represents time as a third dimension, to model person's movement in space and time Kwan and Lee 2003 Kwan and Lee 2003

Landscape Modeling ► 3D Models are frequently used in conjunction with landscape models ► DEMs and TINs are frequently used to represent landscapes ► 3D conceptualizations can be critical to represent viewsheds, watersheds, lines of sight, groundwater, and air pollution

TIN

DEM

Groundwater Modeling

3D Data Models ► The afore-mentioned applications have driven research seeking to develop a 3D Data Model ► Current 3D data models are imperfect and there are many challenges

3D Data Models Current 3D data models are imperfect ► They are not compatible. They may require specialized software. They may not overlay with common formats such as shapefiles ► They are not topological. For example, it may not be possible to calculate routes in buildings because current models do not define topological relationships

ArcScene ► ArcScene is ESRI's 3D software tool. It is integrated with the 3D Analyst Extension ► ArcScene is similar to ArcMap and works well with traditional GIS file formats such as shapefiles, TINs, and rasters ► One can even import 3D models from Google Sketchup into ArcScene

ArcScene..

ArcScene..

Commercial Packages ► Packages such as Maya and 3D Studio Max are commonly used commercial packages ► Such packages tend to be expensive, but they are well-supported and of a high quality ► They are intended to create high quality 3D renders for the purpose of games and movies ► For instance, Shrek was created in Maya

Commercial Packages..

Google Sketchup ► Sketchup is Google's entry into the 3D Modeling software market, now owned by Trimble ► Sketchup is free, and is likely the most widely used software among amateurs ► It is highly intuitive, with a capable graphical interface ► A limitation is that it does not support scripting. Without scripting a model cannot be programmed

Sketchup in Google Earth.. ► One can create a model of one's house, apartment, city block, etc. and load the image directly into Google Earth ► Google makes this process easy via the ability to import scenes from Google Earth, along with associated geolocation data, into Google Sketchup

Building Maker ► sketchup.google.com/3dwh/buildingmaker.html ► Google's building maker utilizes Sketchup and Google Earth technologies to crowd source the construction of 3D models in Google Earth

Building Maker.. ► At the website, you can create a quick 3D model of a building with provided imagery and upload it to Google's 3D warehouse for addition to Google Earth ► Building Maker Tutorial Building Maker Tutorial Building Maker Tutorial

Google's 3D Warehouse ► Via either Sketchup or BuildingMaker, users can contribute 3D models into Google's 3D Warehouse ► Google reviews these models and, if they meet certain criteria, they are admitted to the warehouse ► These models are then integrated into Google Earth

Research on 3D ► Methods to visualize 3D effectively and efficiently ► Dynamics of natural or human behavioral phenomena in a 3D environment ► Raster vs. vector data models for 3D representation, especially the topology of the vector model

Current Research - CASA in UK ► Much formative work in 3D agent based models has been done by Dr. Michael Batty and colleagues at CASA (Center for Advanced Spatial Analysis) ► Their works include modeling pedestrians in carnivals, malls, and downtown streets ► A major belief is that individual dynamics in urban locations have a fine spatial-temporal scale and are best modeled in 3D

Current Research - IRSA in China ► Dr. Jianhua Gong at the Institute of Remote Sensing Applications in Beijing ► Much of the work of his team deals with VGEs (Virtual Geographic Environments) ► VGEs are 3D environments which allow users to interact with other users in a shared space, such interaction can facilitate discussion in contexts such as urban planning, disease control, etc.

IRSA in China..

Local Research ► Sam Copeland simulates disease transmission in hospitals ► The work uses a combination of - agent based models to simulate patients - agent based models to simulate patients and staff and staff - social networks to describe and quantify patient and staff relationships, and patient and staff relationships, and - 3D modeling to represent the hospital - 3D modeling to represent the hospital environment environment

Local Research..

Conclusion ► The expansion of 3D technology opens up new methods to represent the world we live in ► 3D technology brings advances in visualization, representation, and immersion ► As GIS users we should embrace the possibilities offered by 3D technologies