Parveen M. Darbar, Myles E. Powers and Kamau Njuguna

Michael Baker Jr., Corporation

In 1994, as a result of flooding, a pipeline rupture occurred in the San Jacinto River Valley, Texas, causing widespread damage. This incident prompted the Research and Special Programs Administration Office of Pipeline Safety, United States Department of Transportation (USDOT) to research the effects of natural hazards on pipelines. The purpose of the study is to (1) identify locations of the national pipeline infrastructure that face a high probability of failure due to natural disasters, and (2) identify pipeline sections which in the event of failure would have significant adverse socio-economic consequences to the surrounding area. Michael Baker Jr., Inc., is providing technical assistance to USDOT by creating a graphical user interface (GUI) to display and query the natural hazards and consequence data layers developed through this research study. The data layers are in ArcInfo GRID and vector formats..

This paper describes the development of the GUI using ArcView 3.0(a) to assist in integrating GIS data during development of pipeline failure scenarios and evaluate their potential impacts. The development of this customized graphical user interface involves creating special icons and buttons. By simply pointing and clicking on these icons and buttons, the user is able to access any desired section of the natural disaster study database. Additionally, the user is also provided with statistics of the spatial query. This form of customized desktop GIS allows USDOT to manipulate large databases and perform spatial analysis.

 As a result of recent events caused by natural disasters, specifically the San Jacinto floods in Texas, the Office of Pipeline Safety, US Department of Transportation (USDOT) initiated a study to identify areas of the national pipeline infrastructure that present both a high probability of failure due to natural disasters and significant consequences in the event of failure. A high hazard area is defined as proximity to potential destructive forces and a high consequence area is defined by proximity to society. The study used a GIS (ArcInfo) to perform the analysis of the natural disaster hazards to pipelines. The findings of this study will enable the agencies to direct their resources to those areas of the pipeline infrastructure that would have the greatest impact and aid in mitigation activities.

With budget and time constraints, limited computer experience and employee pool considerations, more and more people are implementing desktop mapping applications. Desktop mapping systems on the market today cover a wide variety of applications. It can combine the capabilities of display only, thematic and street-based mapping systems along with the ability to analyze geographic locations and the information linked to these locations. The USDOT plans to implement personal computer (PC) based GIS system using ArcView 3.0(a) to display and query the natural disaster study data sets. A Graphical User Interface (GUI) using ArcView's customization environment enables USDOT personnel to visualize spatial and non spatial information, perform interactive queries and display summary statistics. The ArcView interface serves as an information integration and delivery tool for the different data sets produced for the study.

GIS play an important role in order to efficiently and cost-effectively collect, store, analyze and display large sets of geographically referenced data and facilitate attempts to develop new and more reliable models. Since its development in the 1960s, the application areas of GIS have grown rapidly. The domain of GIS now include environmental planning and resource management, real estate management, transportation planning and utilities/infrastructure management, health care and socio-economic impact assessment, emergency planning and other diverse applications (U. Sunday et al 1996). The users of GIS has also grown rapidly from academia to industry and government agencies at federal, state and local levels. This is by no means an exhaustive set of applications. Most information used in government and industry has a spatial context and the applications are limitless.

Microcomputers (e.g.workstation) have long been used for spatial analysis. Due to their graphical nature and often large data sets, mapping software has traditionally run on workstations or mainframes. But with increasing PC processing power and demand for demographic data on the rise, mapping programs for desktop computers are increasing in popularity (O'Malley 1994). Companies are also making their GIS products available for PCs, for example, Esri's First Street. Sales of GIS software are expected to keep climbing because of lower prices of software, high powered PCs and Macs and development of friendly Graphical User Interface (GUIs) for desktop GIS programs. PC based GIS applications typically involve street mapping and city planning, sales and market analysis, site selection, crime analysis and emergency dispatch systems. In the area of real estate and planning for example, the Baltimore Regional Planning Commission uses GIS to analyze building permit codes to keep up with the pace of development. The city planning office of Jasper, AL uses GIS to analyze information concerning ownership, zoning, existing structures such as schools, flood zones etc to effectively plan future development. Police departments regularly use GIS to display crime incidents on a street map (O'Sullivan 1990). In sales and market analysis, Sears, Roebuck and Co., uses GIS to sort market demographics and location of retail stores (Lee 1992). Desktop mapping can also have an impact on public health. Patterson (1995) discusses how nursing homes use GIS to get a snapshot of the market for services. Montgomery County, MD uses GIS to ensure that land development and transportation infrastructure work together so that both growth and traffic patterns are handled effectively. Northwest Natural Gas (NNG), a distribution company uses GIS to automate or improve leakage and corrosion inspections, work order management and emergency response. They are also conducting gas network modeling and analysis (Hecht 1996).

Some of the better known desktop products are GISPlus, ArcInfo, ArcView, Atlas GIS, MapInfo and Tactician. These packages blend presentation graphics with substantial "what if" analytical capabilities (Lee 1992). Desktop mapping software is gaining importance as a powerful general purpose decision support and presentation tool in government agencies and large corporations across the nation. Esri's ArcView is one of the leading GIS desktop software which gives the user the power to visualize, explore, query and analyze data geographically. ArcView's extensions are add on programs that provide specialized GIS functionality. Some of the extensions are Digitizer, CAD Reader, Spatial Analyst, Network Analyst and Image Analyst. ArcView also has its own development environment that can be customized to meet users needs.

A Graphical User Interface (GUI) enables the user to interact with the computer system by pointing to pictorial representations (icons) and lists of menu items on the screen. Icons allow the user to interact with the computer without having to type commands or memorize them. The most common type of GUI object is the "window" through which the user interacts with the system. Operations on icons for e.g. include moving files, copying them or dropping them in a waste basket. Such interactive methods are often called object oriented because they are based upon classes of objects and operations that they support. Ralston (1994) states that an object oriented approach facilitates the development of appropriate tools for spatial analysis.

ArcView contains its own integrated object oriented programming language and development environment called Avenue. With Avenue one can customize the way ArcView looks, create new tools, modify ArcView standard tools, integrate ArcView with other applications and develop and distribute custom applications on top of ArcView (Esri 1996). Interacting with the user interface is a way to manipulate objects such as views and themes. Avenue scripts can directly access objects through requests. A request is a communication from an object to another and invokes an operation that defines some service to be performed. When a button is clicked or a menu selected, ArcView sends requests to objects. A request may create a new object such as a theme, or it may retrieve information about an object or change the property of an object (e.g. making a theme active).

 A study was conducted to examine the effects of natural disasters on pipelines for the USDOT. ArcInfo GRID was used to perform the analysis. The grid cell resolution was one sq.km. The data for this study was obtained from a variety of sources (public domain and proprietary) to produce the different hazard and consequence data sets. The hazard layers comprised of flood, seismic, landslides and other weather related phenomenon. The consequence layers consisted of demographic, property, potential disruption of commerce, environmental damage, and health risks. Each layer represented a ranking normalized to a scale of 0 - 100, of the level of exposure to natural hazards. Each layer was weighted and combined into a National Hazard Pipeline Index (NPHI). The same process was applied to create the National Pipeline Consequence Index (NPCI) where each layer was ranked from a scale of 0 - 100 for the potential adverse impacts resulting from a pipeline failure. Individual layers were weighted and combined to create the NPCI. In essence, a map was created for each hazard and consequence layer. For e.g. the flood layer shows the degree of flood hazard in the country. Classic GIS overlay analysis was performed to depict areas of pipelines that lie within high hazards and high consequences.

GUI was created using ArcView 3.0(a) with the Spatial Analyst Extension in order to provide USDOT with a simple and easy medium to conduct GIS analysis of the natural disaster database.

One of the most basic and necessary components of GIS design is the user requirements or functional analysis (Calkins 1983; NCGIA 1990; Marble and Wilcox 1991; Emery 1991 and Montgomery and Schuch 1993) because each project is unique and each user has a distinct view of the system and the geographic information produced by it. So from a designer's point of view, user requirements analysis provides the details necessary for a proper conceptual design (Laurini and Thompson 1992). From the user's point of view, the requirements analysis - ideally - assures delivery of an information system optimized to his/her needs. In practice, however there are usually problems in this process. This is becoming increasingly important and noticeable as the GIS field evolves to incorporate users who are neither technical specialists nor spatial professionals, and these users have special needs (Gould 1994).

Laurini and Thompson (1992) state that users are often categorized as not knowing what they want, not being able to communicate their needs, and frequently change their "wish list." One way to view this situation could be to accept it as a natural occurrence and have the design process flexible enough to accommodate changes. An important aspect of this being that a user's apparent lack of knowledge with the information system can be attributed to lack of training. Training should be identified during the requirements analysis as a key factor. By the same token, the designer of the GUI should also learn specifics of the user's environment for the interface to be successful.

ArcInfo's Map Librarian data structure was used to organize the pipeline data purchased from MAPSearch for this study. The pipe library consists of a database directory. The tile workspaces are the different regions. A library called Q3 was created to store FEMA flood zone data by state and by county. Directories were also created to store the hazard and consequence grids and other ArcInfo coverages (Figure 1). All data layers were provided to USDOT on 8mm tape. The data could reside on a server and the users would be able to access the layers on their desktop in ArcView. The librarian data structure allows ArcView to present a thematic representation of the data layers to the user.

Figure 1. Data Organization

Click on graphic to see enlarged view

The ArcView project (application) delivered to USDOT were developed using ArcView Version 3.0(a) and are designed to access data that is stored on a Sun Microsystems SPARC using PCNFSpro Version 3.0 (beta 3). In this environment multiple PC clients can access the same data for query and display. Any editing or analysis which produces new data sets should be performed on client machines to avoid multi user conflicts. ArcView documentation provides information on the minimum and recommended hardware configuration for WIN95 client machines. The ArcView Spatial Analyst extension Version 1.0(a) has the capability to perform functions using the GRID data layers. No additional specific requirements are known to exist at this time.

A pipeline directory can be created under the Esri directory on the C drive. The project can then be loaded from the disk and placed in the C:\Esri\Pipeline directory. To begin the session, one starts ArcView and opens the project (DOT.apr). Special legends and database files are also provided on a separate disk and can be loaded in the same directory or in C:\temp.

Some data in the form of themes, tables and images are already loaded in the View. The View is the window to display themes and a theme is a set of map features linked to their attributes. When the project is opened, the view display is set to an Overview of the Pipeline data with a background of the National Pipeline Hazard Index (Figure 2). Spatial data is organized thematically into different layers or themes and can be seen to the left of the view window. The interface has been customized to perform operations by point and click. In addition to the default ArcView tools and buttons, a few more have been added for specific combination of functions as described below.

Figure 2. Overview

Click on graphic to see enlarged view

Two customized buttons have been added to the right of the help button in ArcView's button bar. The zig zag icon runs the pipeline application. Clicking on this (zig zag line) button, puts a tool menu in the second line of ArcView's Tool interface on the extreme left. The pull down tool has 3 icons (Figure 3) The first is a folder, the second a poly shape and the third an irregular shape (loop). All of these tools primarily define an area of interest through different selection techniques.

Figure 3. Customized Interface

Click on graphic to see enlarged view

• Folder Tool:

The folder tool allows the user to pick a state and county from a list. After the selection is made, the view changes to the selected area. If a county is not selected, the entire state gets selected. A cancel option is also available.

• Poly tool:

Clicking on the poly tool allows the user to select an area by USDOT regions which are Central, Eastern, Southern, Southwest and Western.

• Irregular Shape (loop) Tool:

This tool allows the user to select an area with the mouse by graphically drawing a box around the area of interest. The user can select a county or a group of counties or any area.

All of these tools result in a zoomed in view of the selection highlighted with a striped fill pattern. A new theme of the selection is created and added to the view.

Any of these tools can be used to view the natural disaster study data sets. Different data layers can be added to the view (Figure 4). For example, the distribution of pipelines, or the individual hazard or consequence layers can be added within the region of interest. The add theme option is under the View menu and the dialog box allows the user to choose whether the theme is feature based, grid based or image based.

Clicking on the second customized (X icon) on the ArcView button bar removes the pipeline toolmenu. (Figure 3).

Pipeline Identify Tool

The interface also has two tools added to the existing ArcView Tool interface. The two tools are placed to the right of the create contour tool. The first is a Distance Calculation (measure icon) and the second is the Summarize tool (Icon with an O shape) (Figure 3).

Figure 4. County Level View (Area of Interest)

Click on graphic to see enlarged view

ArcView has an identify tool in its interface which gives the user a listing of the attributes of the data being queried. The measure tool has been designed for getting information for pipelines. Clicking on this tool allows the user to select a pipeline section and a message box appears to show the length of the pipeline in kilometers or (in the units of the current map), the operator name, the commodity type, class and diameter information. The user can also hold down the shift key and select another section of pipeline with the measure tool and this new information will be added to the message box (Figure 5).

Figure 5. Selected Pipeline Attribute Report

Click on graphic to see enlarged view

Population and Property Value Estimates

• Icon with the O shape:

Selecting this icon will allow the user to estimate the total population or the total property value for an area of interest. The tool runs an application which allows the user to draw a circle. After the circle is drawn, the user is prompted to select the grid that has the values for summarizing within the zone. The result is reported in a message box giving the estimated population or housing value for that area (Figure 6).

Figure 6. Population Estimate

Click on graphic to see enlarged view

Although this tool is primarily designed for population and property value estimates, other grids and thematic layers can also be used with the default Summarize tool. For example, a particular county or selected pipelines intersected with the NPHI grid will report summary statistics of the NPHI.

ArcView Clients without Spatial Analyst

For users that do not have access to Spatial Analyst, the interface can be run with an application designed without the ArcView Extension. This application contains image files of the National Pipeline Hazard and Consequence Indexes in BIL format (NPHI.Bil and NPCI.Bil). These images are useful as a backdrop display to view areas of high/low hazard or consequence. No analytical capabilities are associated with these images. The area of interest tools and the pipeline identify tool perform in the same manner as with the other application.

Conclusion

Users who are unfamiliar with a software program always face a learning curve. Mark and Gould (1991) point out that a user's overall goal should not be mastery of a new machine but, rather more productive interaction with geographic information. This illustrates the importance of a Graphical User Interface (GUI) which alleviates the need for highly specialized training. True to the adage "a picture is worth a thousand words," icon-based graphical manipulation of files is highly visual and easy to understand. The challenge is to make the product intuitive and easy to use, but also powerful. This illustrates the importance of a reasonable time framework from a designer's point of view. Development of powerful,sophisticated and user friendly tools require considerable effort, skill and time. In this study one ofthe key factors was to balance the need for detailed functionality with simple and easy to usespatial analysis tools within a given period of time.

This customized ArcView product consists of essential display and query tools. The GUI enables the USDOT to display and query the natural disaster study database effortlessly and efficiently on their desktops in a simple, basic, easy to use format. In the event of any scenario, the USDOT has the ability to view the data in the desired region and make time critical decisions. In an emergency for example, data on residences, schools, fire stations, roads, railroads can be displayed and relayed to crews on field. This user friendly interface will enable the USDOT and Federal Emergency Management Agency (FEMA) to plan for and direct their resources towards vulnerable areas and aid in mitigation services. This interface was useful in providing FEMA with maps of the area affected by the recent earthquake incident in California.

Desktop GIS with customized GUIs are becoming more approachable for business people and for non GIS professionals. Most people in organizations need to share information and resources and perform several tasks simultaneously. By this arrangement of a desktop GIS, they get the advantage of accessing data from a server while retaining the independence, ease of use and low cost of PCs and each individual area or group does not have to reinvent the wheel. The development of in-house GIS capabilities offers the potential to make planning more responsive, accurate, exciting and cost effective. GIS is rapidly emerging as a powerful management tool for enhancing competitiveness, customer service and responsiveness to regulatory requirements.

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Author(s) Information:

Myles E. Powers, GIS Applications Manager
Michael Baker Jr., Corporation
3601 Eisenhower Avenue, Suite 601
Alexandria, VA 22304
Phone: (703) 317-6231
Fax: (703) 960-9125
Email: mepowers@aol.com

Kamau Njuguna, GIS Systems Analyst
Michael Baker Jr., Corporation
3601 Eisenhower Avenue, Suite 601
Alexandria, VA 22304
Phone: (703) 960-8800 Ext: 5236
Fax: (703) 960-9125
Email: knjuguna@mbakercorp.com