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ArcCad: PLANNING THROUGH DATABASE MANAGEMENT

Lawrence D. Hams

Department of Construction Science

University of Cincinnati

Cincinnati, Ohio

Introduction

The potential for disaster is a reality in any community. A chemical plant explosion, river flooding, or earthquake is frequently part of the top news stories in the media. The impact of natural and manufactured disasters on a community generally depends on the nature of the disaster and the preparedness of the community. Disasters have the most adverse effects on those communities that are least prepared.

The job of protecting the community is often the responsibility of a partnership of professionals including federal, state and local civil defense agencies. Civil defense agencies have the immense task of managing disaster response. Experiences of the Federal Emergency Management Agency (F.E.M.A.) show that planning before an occurrence is the only way to assure that a community is prepared. Civil defense coordinators must know many factors about a community, (i.e., location, population, demographics, etc.) to do effective planning.

The intent of this paper is to present a knowledge-based tool that may be used to manage the planning and response task of emergency operations and the potential application to the management and planning of construction (ArcCAD Release 11.2). ArcCAD is a geographical information system engineered for AutoCad Release 11 and 12 by Environmental Systems Research Institute, Incorporated. It is characterized by a topological and georeferenced-database linked to an AutoCad drawing with functions that manipulate the georeferenced data. ArcCAD also provides extensions to the AutoCad drawing which allows manipulation of the Cad data as represented in figure 1.

Definitions

The primary goals of emergency management are to save lives and protect property by developing appropriate operational capabilities. Reaching these goals is simplified by dividing emergency management activities in the following categories: mitigation, preparedness, response and recovery.

1. Mitigation is any action taken to eliminate or reduce the degree of long term risk to human life and property from any type of hazards.

2. Preparedness is any activity taken before an emergency that facilitates the implementation of a coordinated response.

3. Response is any action taken immediately before, during or directly after an emergency occurs to save lives, minimize damage to property, and enhance the effectiveness of recovery.

4. Recovery is short-term activity to return vital life support systems to minimum operating standards; and long-term activity designed to return society to safe and normal activity.

Developing the Disaster Model

To employ the tools of ArcCAD to manage the task associated with disasters, a relational data table of information must be developed for the community under consideration. (figure 2) The data table should be designed to ease the management activities referenced above. The following suggest examples of information for each activity's data table.

Mitigation:

1. Building code information

2. Disaster insurance

3. Land-use management

4. Public education

5. Risk-area mapping

6. Statues/ordinances/variances

7. Tax incentives

Preparedness:

            a. Continuity of government

            b. Emergency Broadcast System

            c. Emergency Operating Centers

            d. Emergency Operations Plans

            e. Emergency exercises

            f. Hazard identification

            g. Sirens

Response:

            a. Emergency medical assistance

            b. Law enforcement response

            c. Fire and Rescue response

            d. Evacuation

            e. Emergency sheltering

            f. Protective action announcements

            g. Emergency Operating Center activation

Recovery:

            a. Damage Assessment

            b. Debris clearance

            c. Decontamination

            d. Counseling

            e. Disaster Assistance

            f. Temporary housing

            g. Reconstruction

A graphical data file describing the community should be generated in an Autocad relatable file format. This may be obtained on floppy disk or compact-disk format from the local building department or developed by an experienced AutoCad programmer. The Cad drawing should be detailed to the exact extent of the geographic area it represents (figure 3). An accurate method of obtaining this match is through aerial photographic documentation of the area, translated or digitized to an AutoCad drawing format such as *.DWG/DXF/DXB/ or DXX (where * = filename). This file is the basis for the development of the ArcCad model. Entities of the AutoCad drawing are the foundational links to ArcCad.

Developing the Construction Model:

A similar model for the management and planning of construction could be developed for the application of ArcCad. The data tables would be consistent with the management activities associated with the specific project or projects. As an AutoCad-based application, ArcCad seamlessly integrates with hundreds of other AutoCad compatible programs currently used in construction management and planning. It can provide such functionality as scanned raster image display and editing, project management, civil engineering, animation, performance charts and surface modeling. I It should be noted that AutoCad Release 11 or 12 and ArcCad Release 11.2 or 11.3 are required to supports DBASE compatible scheduling and estimating data table links to the AutoCad images. A specialized Autolisp programing extension tool must be written to integrate any non-Dbase program used in your classroom instruction. An Autolisp extension tool would be necessary for example to bring compatibility with ArcCad and Primavera. Review of the software programmer reference manual for the application should alert the user to the product's language compatibility. Developing Autolisp programming links requires a knowledgeable technician experienced with this AutoCad-based language.

ArcCad tools are specifically suited for corridor analysis for management at the construction site. The integration of CAD and GIS provides the ideal platform for drainage and watershed analysis. Superintendents could also use ArcCad for inside and outside the site analysis to support site planning, selection, and inventory control.

ArcCad provides for traditional AutoCad-based coordinate geometry, topography, and road and subdivision design software while building a GIS database that is topologically correct. The GIS database would simplify civil engineering decisions involving soil analysis and classification and any other operation involving the information contained in the database.

The ArcCAD Theme

The first step in developing the ArcCAD model is to define a "theme." A theme is a collection of similar geographic features in a relational data table generally called a feature attribute table. This table joins AutoCad entities to Geographic Information System (GIS) data sets (figure 4). The GIS data set are files contained in a subdirectory that includes coordinate locations and also a feature attribute table.

Defining the theme creates a limited GIS data set joined to the entities of the AutoCad drawing. A data set file can be developed separately using any database software compatible with DBASE files. Through the use of a common identifier (usually a field category) the files can be merged with those created by ArcCAD.

Each theme has a unique name, a feature class, a pointer referencing a corresponding, GIS data set, and a symbol number representing the type of data defined in the theme. Themes are stored as point entities in the AutoCad drawing on a special layer named ESIU_THEMES. Themes are stored in ArcCAD as either a point attributes, line attributes, polygon attribute or data file. The theme definition is designed to correspond to the AutoCad entities contained in the drawing. In theory this allows each entity in the AutoCad drawing to be defined as an ArcCAD theme. ArcCAD assigns an attribute table to each feature type that contains a file reference to the data set defining the theme.

The function of the theme is to integrate the AutoCad drawing data and the GIS data set (figure 5). The integration is not a physical manipulation of the data, but only a method of cataloging and extracting specific information from the two data sources for study. All ArcCad functions are performed on the theme as defined, leaving the original data files intact. The theme is stored on the AutoCad drawing and contains information about access to the GIS data set, specifically, which information is accessible from the data set. Once a theme is defined, only the theme name is needed to perform any GIS functions.

The ArcCAD Feature:

The features in the ArcCAD model can be graphics files of drawing entities, or a data file of fields and records. Any feature is stored as a block and assigned an attribute table. There are two special ArcCAD data types that are set up to provide access to the ArcCAD features: a feature name and a feature selection set. There is usually one feature selection set maintained for each theme defined in the drawing. Initially, all features belonging to a database are selected for that theme's selection set. The user can manipulate the feature selection sets to display desired features and their corresponding attribute values. A feature selection set is grouped together on a series of spatial. Logical and arithmetic expressions. To manipulate features the user must show which objects are included in the function. This process involves the selection of features based upon combinations of spatial, graphical and attribute criterion specified as a series of logical expressions. The feature name is the identifier used to select data for the feature selection set.

Query and Display in ArcCAD:

The ability to query and select features from your database is an important part of any GIS application. Query and selection operations are common for analysis of your GIS database. Selection from a drawing that meet certain criteria are important in creating maps, generating reports, and performing geographic analysis.

ArcCAD includes several operations for the display of geographic features. The operation displays information as the same line type, marker, or shade. This is useful if the user is highlighting a selected set of features or if differentiation between feature is not wanted. The ArcCAD display command creates new entities in the drawing. The layer on which features are displayed can be controlled. Unless otherwise specified, the features are displayed as entities on the current layer.

Database Analysis:

The ability of a GIS to do spatial analysis set GIS technology apart from Cad, automated mapping, graphic programs, and systems that tie graphics to attributes, but do not support a topological database model. Spatial analysis is the key to solving problems that face our natural and urban environments (figure 6). By using GIS for spatial analysis, we can synthesize and display map data in creative ways. We can also combine multiple themes to determine their spatial relationships.

Through the tools of ArcCAD, we can develop a Planning Algorithm. The procedural sequence of the algorithm would be as follows:

A= (T)(G)(F)(D)/(Q+Dp)…..where

A= Planning Analysis                 D= Database Development

T= Theme Definition                  Q= Data Query

G= Graphic Documentation       Dp= Display

F= Feature Development

Conclusions

The primary goals of management will become the themes for the algorithm. The definitions of the management activities will define the core about which the features data set can be formulated. The data set should contain information such as that suggested by F.E.M.A. in the Definitions above. Developing a data table with these four categories is essential to assure universally recognition by disaster agencies in this country. Universal recognition of data sets developed for construction would also be essential when defining the parameters of construction research. Universal recognition assures the results or conclusions reached via the algorithm are qualified.

This paper has presented a summary model for disaster planning that would use the same data currently employed by local, state and federal emergency management personnel. It suggests that the control of this data using the tools of ArcCad, a computer driven application would bring Disaster Planning to a new level. It suggests that a similar model could be developed for academic and industry applications in the field of construction. This application teas the potential of maximizing the planning efforts of the emergency management planning team or the construction management team, simplifying the handling of more information categories in their planning. The development and application of an ArcCad model such as this has the certainty of giving the most open, flexible, and expandable solutions in the GIS industry today. Further research is planned to develop and apply algorithms specific to construction. The disaster planning research was funded through the University of Cincinnati Program Advisory Committee.

References

Environmental Systems Research Institute, Inc., Introducing ArcCAD Release 11, Course Manual (Redlands, Environmental Systems Research Institute, Inc. , 1991 ), 11.

Environmental Systems Research Institute, Inc., ArcCAD Command Reference (Redlands, Environmental Systems Research Institute, 1nc. , 1992).

Federal Emergency Management Agency, Guidelines For Public Officials on Emergency Planning- Are You Ready for The Next Disaster?, (FEMA-180, 1989).

Hamilton County, Ohio Office of Emergency Management and Civil Defense, Emergency Operation Plan (Hamilton County, Ohio Office of Emergency Management and Civil Defense, 1992).