Publication: 3D Urban Modelling data of the BLPG Conurbation, Venezuela

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3D URBAN INTERACTIVITY: GIS + VRML: THE EXPERIENCE OF BLPG PROJECT Gabriela Bustos. María G. González. Iván Burgos and Javier Oliva University of Zulia Venezuela ABSTRACT This paper points out the experience developed in the BLPG Project (Barcelona, Puerto la Cruz, Lecheria and Guanta) by the faculty of Architecture and Design of the University of Zulia in Maracaibo, Venezuela, where a 3D Interactive Virtual World using VRML (Virtual Reality Modelling Language) was linked to a 2D based Geographic Information System (GIS) supporting the urban analysis process of the conurbation of Barcelona, Puerto la Cruz, Lechería and Guanta (BLPG), visualizing in a 3D and interactive approach the urban characteristics of a particular area. Paper also explains how the GIS, Virtual Worlds, Virtual Interactive Menus and connections were built using VRML, Java Scripts, Hot Links and Hot Potato scripts. This work supports an urban analysis methodology created for BLPG Project. All data, two and threedimensional, was obtained from AutoCad® drawings.

INTRODUCTION The role of universities in the Venezuelan society The Venezuelan universities have a double function: first, the generation and integration of scientific and humanistic knowledge and second, knowledge has to be oriented to solve specific necessities of the state and the country.

This is the main reason why Faculty of Architecture and Design (FADLUZ) and Anzoátegui State Government, located in the nor-east coast of Venezuela, enter into a covenant, where University of Zulia through FADLUZ participates in several studies of particular urban phenomena in the metropolitan area of conurbation BLPG. This participation represents an opportunity to relate academic practice and social and economical realities of informal urban areas of the country.

BLPG Conurbation In Venezuela, the excessive demographical growing in the National Cities System presents a particular form materialized on a non equal development in every urban nucleus, on other words, for each formal and controlled developments there are one or many informal and non controlled developments, which are more dynamic, bigger and precarious; that reflect the vast social differences and has been increasing through last decades in the national reality of venezuelan society.

BLPG Conurbation is a clear example about above description and it is constituted by four urban centers: 1) Barcelona City, which concentrates administrative and political activities

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and services; 2) Puerto La Cruz City, with a strong tendency to fusion to Barcelona and commercial and oil industry activities; 3) Lechería is a tourist and recreational location with an important hotel and lodging structure and relative services and 4) Guanta, port oil industry activities and small village constituted by fisherman community, becoming the most important port in the east of the country.

Figure 1 : Conurbation location.

BLPG Conurbation concentrates a population of 600.000 inhabitants and has an approximate 19.000 Has. (46.930 acres), and 53% of this area is occupied by informal and uncontrollable settlements

Figure 2: Conurbation images.

BLPG project Result of the agreement between FADLUZ and Anzoátegui State Government was the BLPG Project and it has three fundamental phases: 1) Exploration which means a revision of documentation and exchange of information and several visits to the location; 2) Diagnosis, that is the study zone analysis and 3) Final Design Proposal for organization and intervention of the informal settlements located in the Conurbation.

The phases are applied in three cases defined in the project: a) The conurbation by itself, b) The Railroad zone, an old 27 kilometers (16.74 miles) long railway, used for coal transportation from Naricual mines in the south to Guanta port in the north. This railroad is actually out of service and now is a suburban habitat, highly precarious and with a very low human development index (HDI), c) Cerro Vidoño (Vidoño Hill), located in a privileged place in the middle of conurbation, facing to Caribbean Sea, with a panoramic view of all the conurbation possessing a very high tourist potential.

As a strategic step for the diagnosis generation, a Geographic Information System was used, so, looking for a data complete vision in the GIS, incorporation of Virtual Reality Non Immersive Technology was formulated using VRML version 2.0 for Virtual World creation,

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adding three important aspects to the urban three-dimensional view: 1) Interaction, 2) Immersion and 3) freeware software viewer without license expenses, very important point in developing countries as Venezuela.

PREVIOUS WORKS The School of Architecture and Design of the University of Zulia (FADLUZ) has been developing during the last years, diverse social, spatial and architectural analysis projects of urban zones from Venezuela’s territory, using new technologies as the Geographic Information Systems, and more recently, the creation of virtual worlds, as a complement of traditional urban analysis methods, among these projects, can be recognized the Urban Local Developing Plan for Maracaibo (1993), the GIS – Tamare (1995-1996), the Physical Planning Unit Maracaibo Norte (2002-2003) and the virtual menus with VRML to interiors design: the threshold to the Synthetic Environment Laboratory (SELab-2002).

At international level some experiences related to SIG and VRML connections, have been developed: a.) Links of virtual worlds and database on a Web Site using a Virtual Reality Viewer which permits manipulation and edition of models on line and real time. (Zlatanova, 1999) b.) Connections between 2D GIS data and spreadsheet, where is possible to modify information to build a VRML file using programming basic structures. (Huber, 2000). c.) Using Avenue scripts is possible to make changes to the ArcView® databases (Ex: color and height ) to generate a 3D model with WRL extension. (Venue, Centre for Advanced for Spatial Análisis, 1998) OBJECTIVES The objective of this work is to express the roll that GIS connected to virtual worlds has carried out in the urban analysis made in the conurbation BLPG, allowing to show not only the graphic representation of descriptive data in the traditional way, as to illustrate in an interactive and three – dimensional approach the basics characteristics of two of the cases of study: Cerro Vidoño and the Railroad Zone. Also the focus is to show the digital production of project BLPG, sharing the methodology used in the GIS and virtual worlds design, as well as to indicate the reasons because of these digital tools (GIS, VRML and Java Script) were used as assistants in the urban analysis made in the conurbation.

METHODOLOGY The idea of this work is not to make large explanations of a GIS elements but just name and briefly talk about them: a) alphanumeric element (tables or geodata); b) graphic-topological element (points, lines and polygons or coverages) and c) in very special cases as ours, 3D Virtual Worlds element.

Additionally, is important to explain the meaning of MUGIEL (Minimal Urban Geographic Information ELement) because in developing countries, it is the core of the possibility of the information aggregation.

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In Venezuela, as many developing Latin-American countries, cadastral and urban information has been handled without seriousness and non adequate methodological discipline, so, the ideal information (fine information or very low level of it) as lot information (parcel info) which is easy to get in all the developed countries, is not available in our countries, where the information by aggregation is just possible in some few cases, that is the reason because the term MUGIEL had to be generated, in other words, in order to work with GIS, not all the data is possible to obtained to, so, only is possible to work with the available information (graphical and alphanumerical).

In our case, three different MUGIEL´s (as a coverage or polygon) were used: settlements, lots and municipal divisions. Only partial information of each MUGIEL was provided by different sources.

STUDY COVER

MUGIEL

TOPOLOGY

Railroad

Settlement

Polygon

Vidoño

Lot

Polygon

BLPG Conurbation

Settlement

Polygon

Municipal division

Polygon

Table 1: Adopted criteria summary.

Because of above words, all information is structured in the same way for the all study sectors, using for specific cases the MUGIEL available for them. It means, that the data model is the same for the Conurbation BLPG, instead the information, which is not completely available in every component.

Figure 3: Entity – Relation Model.

The theory of the data model is showed in the figure 3, under the entity relation model graphic, where a generic MUGIEL related with itself, is selected as the minimal urban information unit During the Normalization Process (3FN), a split of tables of the same entity is generated

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Components of the proposal system a) Graphic components

Figure 4: Graphic components.

Using the E/R Model, theory express that graphic is an attribute of MUGIEL, as a coverage (polygon of information), that is the reason to have several treatments in different scales of information. As result of this explanation see table 1.

All polygons (coverage or MUGIEL´s) are strictly coded by an unique code (figure 5), which is related to the same code used in the alphanumerical tables (in MSAccess®), in order to establish a link between tables and graphics, that is called Connector Principle, because once the MUGIEL is coded, it is able to be connected with every table which has an attribute of connection or unique code.

Figure 5: Graphic components. Connector Principle. b) Alphanumerical tables or geodata Database is generated in Microsoft Access XP® because three reasons: 1) is accessible in all windows operating systems; 2) is a component of Office Program of Microsoft in all version since 1997 and 3) the most important, single and complex queries, generate a virtual relation or another table, which can be used as a simple table in ArcView®, in Access format or DBF format, as you wish.

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There are several related entities (figure . Relations in MSAccess), making possible sailing through the whole database. Those entities have attributes and each attribute has its own domains with a range of continuous and discreet values.

Figure 6: Data tables relation in MS Access. c) Three-Dimensional virtual worlds The proposal of the connect GIS to Virtual Worlds, which helps to illustrate the physical reality of the study cases: Cerro Vidoño and Railroad Zone, using VRML and its facilities as interaction, movement’s autonomy, scene manipulation, objects handle and others potential and useful routines created in Java Scripts, turn interesting new ways of exploration of urban theme.

The Three-dimensional construction in both cases of study, include topography and existing buildings. For this phase, AutoCAD 2002, 3DS MAX 3.0 and VRML language, were used.

First, a methodology was developed to convert information from AutoCAD to VRML to avoid heavy files for the 3D model and view: 1) Closed polylines conversion of terrain level from AutoCAD 14 to 2002.

2) Verify Lwpolyline not converted to polylines.

3) Save file with DWG or DXF extensions from versions 12 or 13.

4) Coordinates x,y,z extraction of all vertex of the selected polylines in a text file format using Plist.lsp (Lisp program) of Tony Hotchkiss.

5) Change file extension from TXT to DAT 6) Generation of topographical grid using program TERRAIN2.DLU (http://www.habware.at/duck3.html ) 7) Export file as VRML97 format.

Second, roads, paths and other elements were placed as an image (texture). Images had a previous work of dimensions to avoid deformations, because most of them are taken from the real environment.

Then, files were divided, to get small files, depending and related to the different zones which form the whole conurbation.

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Figure 7: Virtual Worlds generation process.

Union of topography and buildings, was made through a unique template file named “total Inline”. For each project, including parts as nodes Inline, small files in TXT format were created with the coordinates data, to avoid to get information from a large file.

Figures 8 and 9: File “tolalInlineVF” and file BGuzmán as nodes Inline.

Virtual menu in VRML for urban analysis Virtual Menu was designed as interface to make easy the different interactions and to facilitate the lecture of functions, also is important not to create visual obstacles to view the model, for that reason there is an on/off button, to control the menu visualization.

The principle of this part was based on a previous work(Bustos, 2002), so it is viable to edit the menu to adapt it for the present work, so several dimensions of the urban structure as human dimension, social dimension, economic dimension; are to be able to be represented on different buttons. Changing colours, transparency, hidden objects control, change scenes, sound control and so on are also possible using virtual menu. Java scripts in a Script Node, were used to generate virtual menu in VRML

Figure 10: Virtual Menu general interfase image.

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RESULTS The virtual world development starts from the base world construction to extract a portion area of each case of study and illustrate which could be the virtual representation of urban analysis indicators.

Figures 11 and 12: Base Virtual Worlds: Railroad and Vidoño Hill.

In each case of study the 3D interactivity is the concept to represent social realities and urban dynamics using sector’s videos, sounds and images attached to fences and facades inside the virtual world, with the same criteria it is sought to indicate the urban grain topology, land use, routes relevance, important nodes, densities, institutional reality and political division throughout the urban study buttons from the virtual menu. Each one of those elements are present in only one world, is call as “Inline” node to optimize the virtual world operation, and the interactions controlled by the virtual menus to the urban analysis described in the methodology. The keys of this proposal are: 3D information interaction and visitant’s senses stimulation, which confirm the VRML main advantages use in urban studies for developing countries.

Figures 13 and 14: Virtual Menu: Settlement G. Lander in the Railroad.

Land use and natural dimension buttons actives.

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Figures 15 and 16. Virtual Menu: Settlement G. Lander in the Railroad.

Social and political dimension buttons actives.

As a consequence of the implementation of this urban interactive analysis strategy, using virtual menu make easy reading of the elements in a direct approach, more real and impressive to the senses, increasing the urban planner’s and architect’s urban space perception as well as non specialised persons in the field of the urban data reading and understanding, taking decisions and elaborating proposals, of urban – social reality projection, analysis results diffusion and promotion to the communities, publishing virtual worlds in the BLPG Project web site, among the most relevant contributions.

The construction of large three-dimensional virtual worlds, with complex topographic features, and the interactive options generation using virtual menu in the same virtual world created to manipulate urban data with JavaScript and VRML, becomes first application of this type for urban analysis in Latin America, going beyond technologic limitations and solving the interactive construction of multiples urban models, with a free charge platform, opening the sailing accessibility to any user.

Figures 17 and 18: GIS and railroad Virtual World (VRML file in. wrl and .txt formats) connection.

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The 3D virtual world component results in an extremely useful tool to application in urban studies; in this case, a 3D graphic supporting GIS. In this project GIS – VRML Virtual Worlds connection is proposed, and the edition of the graphic data files using Hot Links (ESRI) and Hot Potato (Kenneth McVay) from ArcView. The proposal represents the interaction from ArcView to VRML and its files, in this moment is not considered yet, real time editions from VRML or any other file to ArcView.

CONCLUSION The proposal of interactive living words linked with the GIS open the possibility to paste a virtual file to each urban area 2d with the 3d information, including the virtual menu of urban analysis. It displays in a complementary manner the data from the GIS, facilitating the visualization and the process to make the urban analysis. The combination of this two technologies platform with a base in a interactive concept, using Hot Links and Hot Potato from ArcView, allowing to associate 2d data to 3d data, as the possibility to open a VRML text file, editing information to refresh the wrl file.

The creation of virtual menu using VRML to aid the urban analysis through the developing of Script nodes, constitute an original contribution of this project as it is a support to the 3d interactive concept of the proposal, offering options to make interventions in the virtual worlds on real time, without programming the text wrl file, or using VRML editors, showing since the visual and hearing senses with non immersive virtual reality, each one of the components of information from the dimensions in the established urban analysis.

At the School of Architectural and Design of University of Zulia, The BLPG Project constitutes the first integrated experience in an urban proposal applying GIS + VRML, as support of urban studies for the services of the professional community and the social communities deeply involved in the urban areas.

REFERENCES Bustos, G. (2002): Virtual Menus whit VRML to Interiors Design: the threshold to the Synthetic Environments Laboratory. University of Zulia, School of Architecture and Design. Graduate Studies Division.– LUZ. Venezuela 2002.

Environmental Systems Research Institute (2004). http://www.esri.com Huber, B. (2000): Adding dimensions to GIS with VRML, Directions Magazine. http://www.directionsmag.com/features.php?feature_id=36 McVay, K. (1998): Hotpotato Avenue Script. http://www.esri.com Raper, J. , McCarthy, T and Williams, N. (1997): Integrating ArcView and Geographically Referenced VRML Models in Real Time. 1997 ESRI User Conference. http://gis.esri.com/library/userconf/proc97/proc97/abstract/a685.htm Smith, A., Dodge, M and Doyle, S. (1998): Visual Communication in Urban Planning and Urban Design. http://www.agocg.ac.uk/reports/visual/casestud/smith/visual1.htm VENUE Project (1998): Adding 3D visualisation Capabilities to GIS, Centre for Advanced for Spatial Abalysis, Univesrity College London, 1998. http://www.casa.ucl.ac.uk/venue/3d_visualisation.html Zlatanova, Siyka. (1999): VRML for 3D GIS. The Netherlands. http://www.gdmc.nl/zlatanova/thesis/html/refer/ps/sz_bra99.pdf

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CVS OF THE AUTHORS Gabriela Bustos, Architect, Master Degree in Informatics in Architecture.

Architectural Design and Virtual Reality Professor and Researcher, School of Architecture and Design – University of Zulia.

Maria G. Gonzalez, Architect, Master Degree in Informatics in Architecture.

GIS Researcher, School of Architecture and Design - University of Zulia.

Informatics Professor, Universidad Dr. Jose Gregorio Hernandez.

Ivan Burgos, Architect, Master Degree in Computer Sciences.

Informatics Professor, School of Architecture and Design – University of Zulia.

Javier J. Oliva, Architect.

Informatics Professor, School of Architecture and Design – University of Zulia.

CO-ODINATES Arch. Gabriela Bustos, Arch. Maria G Gonzalez, Arch. Ivan Burgos and Arch. Javier J. Oliva School of Architecture and Design Universidad del Zulia Maracaibo Venezuela Tel. +58 (261) 759.8964 E-mail bustosgabriela@yahoo.es E-mail mgabriela1977@yahoo.es E-mail iburgos@luz.edu.ve E-mail joliva@luz.edu.ve

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