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IntroductionGeographic information systems (GIS) has revolu-tionized the way governments provide information.The spatial manipulation of cartographic (map)data together with attribute data (additional dataabout geography, parcels, and other mapped fea-tures) makes geographic information systemsunique. In the development of the Orange County,Florida, GIS system, aerial photographs, parcelmaps, tax roll, and appraisal file data are all relatedand linked in the same system for seamless access.

There are several ways of implementing a multi-purpose GIS system, depending on the goals andobjectives. Many government jurisdictions haveimplemented GIS without a full understanding ofall the issues necessary to design a system that willserve future needs as well as current. This article ex-amines the processes and procedures Orange

County and the Orange County PropertyAppraiser’s Office used to re-engineer the county’slegacy GIS into a successful multi-user, multipur-pose system, which uses survey-accurate global po-sitioning system (GPS) points and ties parcel mapsto land corners using coordinate geometry. This in-cludes the essentials of how the project evolved, thedevelopment of interlocal agreements, conversion ofexisting data, the re-engineering process, and thedevelopment of an enterprise desktop access pro-gram.

Recognizing a NeedGetting countywide GIS data into the hands of us-ers and the public historically had been a difficulttask in Orange County. The county recognized theneed to implement what it thought would be en-terprise GIS back in 1985, viewing the idea that allcounty agencies have on-demand access to spatialdata and related information as a breakthrough ininformation processing. The Orange County Boardof County Commissioners (BCC) entered into aninterlocal agreement with the county property ap-praiser and the City of Orlando to design andimplement the system in the late 1980s.

Orange County is located in the east central part

An Enterprise GIS Solution forIntegrating GIS and CAMAKevin P. Hardester

Kevin P. Hardester is the chief of staff for the OrangeCounty Property Appraiser’s Office in Orlando, Florida.

The statements made or views expressed by authors inAssessment Journal do not necessarily represent apolicy position of the International Association of As-sessing Officers.

Abstract

Making countywide GIS data available to local government and the public wasa challenge for Orange County, Florida. This article examines the processes andprocedures the county used to re-engineer the legacy GIS into a successful,user-friendly, multipurpose system.

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of Florida and is one of the fastest growing countiesin the nation. The county covers 955 square milesand contains 330,000 real estate parcels and apopulation that is approaching one million. It is amajor tourist destination, with flights arriving atOrlando International Airport from various domes-tic and international locations. Disney World, Uni-versal Studios East, and Sea World are the major at-tractions, and the county is a stepping off point toFlorida’s famous beaches. The area has attractedmany businesses to its sunny climate and affordableliving and recreational opportunities. Businessesbenefit from having the University of CentralFlorida graduating qualified candidates for a varietyof careers. The county has thirteen bustling mu-nicipalities, the largest of which is the City of Or-lando.

In 1985, HDR Consulting was hired to developthe original GIS plan for Orange County. The BCChired several consultants to work with staff in theplanning and implementation stages. In 1988,Baymont Engineering was selected for the conver-sion of the parcel “base” maps and associated textand annotation. The BCC also hired survey con-sultants to densify the geodetic control network touse in tying the property ownership maps to surveycontrol. However, problems arose with the surveyconsultant operation, and that part of the projectwas scrapped. The BCC moved forward withBaymont Engineering in digitizing the parcel maps,and a decision was made to digitize the propertyappraiser’s existing paper and mylar parcel mapsand perform rubber-sheeting. GeoVision was pur-chased as the GIS software.

In 1990, the digitization of the parcel maps wascomplete and, according to the county’s GISproject coordinator, the street address centerlineproject was finished in 1992. When the county’sconsultant was asked what was next on the agenda,his response was that he would have to fix the spa-tial accuracy problems. This answer would prove tobe part of the undoing of the GeoVision GIS sys-tem in its maintainability and overall credibility forall agencies. Simply put, the GIS did not tie to realworld survey coordinates and could have dimen-sional inaccuracies of up to 200 feet or more. Thebase map was a digitized, rubber-sheeted copy ofexisting paper parcel maps. Layers of other spatialdata placed on top of the parcel layer would have tobe moved as the parcel data changed over time,proving to be a frustrating process with no resolu-tion in sight.

Bumps in the RoadIn 1993, GeoVision went into receivership, and thepartnership among the BCC, the property ap-praiser, and the City of Orlando dissolved. Thepartners agreed to share data, but it was decidedthat each would assume responsibility for its ownGIS needs and staffing. At the time, the county’sGIS project coordinator’s contract was not renewed,and eight consultants were released.

GeoVision was subsequently purchased bySystemhouse, Inc., and the software was renamedVision. The BCC and the property appraiser con-tinued to use Vision, but the enterprise systemoriginally envisioned did not materialize. Convert-ing from Vision’s data format to other formats foruser requests proved difficult, and the requests oftencould not be met. The system did not have a user-friendly interface, and the BCC and property ap-praiser had to rely on a select few GIS specialists toperform complex programming to accomplish eventhe simplest tasks.

In early 1998, the county released a report defin-ing what needed to be done to accomplish theplan’s original goals. The tasks that remained were

• Establishing GPS/geodetic control point densifi-cation throughout the county

• Creating photogrammetry and a natural resourcedatabase

• Creating public access to GIS data• Creating a street name petition application• Linking the permit system to GIS• Creating a public safety interface• Creating a traffic sign inventory• Creating a zoning code enforcement application

Fortunately, between 1993 and 1998, the Or-ange County surveyor continued to make progressin establishing a three-mile-high precision grid ofGPS pairs of survey control monuments throughoutthe county. He also worked to densify a half-milegrid of control points for certified corner records inthree townships in the northwest corner of thecounty. This work would prove to be extremelyvaluable in completing some of the original GISgoals.

Back on TrackIn December 1998, the property appraiser and thenewly hired assistant property appraiser, GIS man-ager, and GIS analyst established a new plan.Within the first forty-five days, a comprehensive

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plan was established and put into motion thatwould bring the county, the property appraiser,and a number of municipalities into a newinterlocal agreement. The plan required the conver-sion of the old system to ESRI’s ArcInfo GIS withSpatial Data Engine (SDE) in an Oracle relationaldatabase.

The selected hardware configuration would sup-port a client/server computer network runningMicrosoft NT on the desktop and Unix for the da-tabase and file server. Microsoft NT was also se-lected as the ArcInfo application server for the map-pers. A Sun Microsystem 4500 Unix computer wasselected as the database server, a DEC Alpha 4100for the web server, and a Compaq Proliant 5500 forthe map web server. The local area network usesSamba for PC to Unix connectivity over TCP/IP us-ing 100MB Ethernet connections. The wide areanetwork uses fiber optics, and the Internet uses aT1 line.

The implementation plan called for developing a

Figure 1Initial ProMap Screen

user-friendly interface allowing comprehensiveagency and interagency access, as well as the devel-opment of a map Internet for public access. Theplan’s second stage called for the re-engineering ofthe parcel layer using survey control and coordinategeometry to depict real world accuracy of the mapfeatures, which would be the foundation of all fu-ture map feature placement and would eliminateerroneous and redundant work.

The property appraiser’s GIS staff (the GIS man-ager, two GIS analysts, and a GIS operations tech-nician) established a detailed conversion plan thatwould include the development of several applica-tions to view and maintain the new system. Theconversion process would prove to be an enlighten-ing excursion into database analysis of the Visionsystem and the design of the new GIS, based onESRI’s data format and its SDE stored within anOracle database. The plan called for using Safe Soft-ware, Inc.’s FME software to convert the GIS data-bases, a particularly challenging task, and took sev-

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eral weeks of program modifications and intensiveconversion reiterations before a completely success-ful conversion was accomplished.

In-house GIS staff was tasked in developing auser-friendly, comprehensive enterprise access pro-gram to view, query, and analyze data, as well asplot maps. The application, called ProMap (see fig-ure 1), was developed using a customized version ofESRI’s ArcView accessing the SDE database withconnection to a comprehensive list of Oracle tableshosting detailed property attributes from the prop-erty appraiser’s master appraisal and tax roll files.Response time to access the full map extent of Or-ange County’s 955 square miles now averages aboutone to two seconds.

ProMap allows access to any and all parcels byseveral search options. Standard features such aspan, zoom, and select map features are available bydefault. Searches are run by owner name, propertyaddress, parcel identification number, street inter-section, or neighborhood. Other themes, such aszoning, future land use, flood plain, and municipal

boundaries can be added into the view. Variousthematic maps can be created through a pull-downmenu for assessed values, neighborhoods, land usestrata, city codes, sales year, sale-to-assessed valueratio, and sales price. The program plots maps at11” × 17”, 25” × 25”, 36” × 36”, and aerials at 25”× 25”. Properties automatically can be labeled withdata elements in the database, including parcelnumbers, sales data, and subdivision names. Thesystem allows for simple reporting, on-demandprinting of mailing lists, and exporting selected par-cel data to a spreadsheet or data file. The systemcreates parcel summary reports, land reports, andlegal description reports for selected parcels. It cre-ates a pin map from land use codes or a query, andautomatic buffering is a standard feature. Buffersare created around a parcel, line, rectangle, point,circle, or around a custom negative buffer around acircle, polygon, or rectangle. A comparable salesanalysis algorithm is available in ProMap, whichcreates a professional comparable sales analysis andreport. This is useful in validating assessed values at

Figure 2PAMAP (Parcel Maintenance Screen)

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the Value Adjustment Board and explaining marketvalue to taxpayers and the general public.

Several unexpected benefits were achieved withthe conversion of the spatial database and the devel-opment of ProMap. It was discovered the legacydata did not always adhere to strict standards ofmapping consistency for schema, placement of at-tribute data, and closure of parcel polygons. Muchof this was corrected through the conversion qualitycontrol programming, confirming the need to ini-tiate a formal implementation strategy for consis-tent schema and data standards to be used in theparcel re-engineering project. An additional benefitwas the development of closer communication andcollaboration among various county agencies andoffice staff in developing an enterprise program use-ful to all. This proved to be extremely productive,opening communication that had been limited.The director of appraisal services recognized thepower of ProMap to coordinate weekly work pack-ets for each field appraiser to produce the first rout-ing program that automatically showed the location

of properties to be inspected.A parcel maintenance application was developed,

PAMAP (see figure 2), to maintain the newly con-verted parcel layer. This was achieved using ArcInfoODE and Microsoft Visual Basic to create a graphi-cal user interface (GUI). PAMAP was developed toallow editing of all map features and has a robustcoordinate geometry (COGO) interface and a con-nection for a digitizer.

Using New TechnologiesThe GIS Intranet and Internet were developed anddeployed in December 1999. The Intranet andInternet were developed using ESRI Map ObjectsInternet Map Server and Microsoft Visual Basic. Allemployees, local and remote, are connected to themap server for access to the Intranet, providing lessfunctionality than ProMap, but more than theInternet program. The Internet map application(see figure 3) was developed for simple, user-friendly connection to the GIS database with theautomatic ability to view more detailed data as the

Figure 3Internet Map Screen

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user zooms in to a specific area. It was connected tothe property appraiser’s existing website(www.ocpafl.org) for integration with the tax rolland appraisal databases. This allows the public totoggle back and forth between databases. TheInternet map application received 22,429 hits and172,734 requests in January 2000.

The entire conversion process, which includedacquiring ESRI software products, converting thelegacy GIS data, the development of ProMap forenterprise access, PAMAP for parcel maintenance,the Intranet for quick local government access, andthe Internet for public access, was accomplishedwithin eight months. The entire map extent of Or-ange County and its associated data now can be ac-cessed in a variety of ways, depending on the com-plexity of the requestor’s needs. In addition, aspecial conversion program was written to extractthe converted ESRI SDE spatial data to five addi-tional formats (shape files, E00 or ArcInfo cover-ages, DXF, MIF, and DGN) to satisfy public re-quests, a major deficiency with the legacy system.

Through interlocal agreements, the property ap-praiser allows government agencies to link directlyto the master GIS database and distribute copies ofProMap for high performance GIS access. Data canalso be obtained off-line on a CD-Rom, and anyonecan access the system through the Internet. Thegoal of having a user-friendly enterprise GIS systemhas finally been realized.

Having accomplished this primary goal, theproperty appraiser set out to accomplish the next—creating a spatially accurate parcel base map withdigital ortho-rectified photography and selectedplanimetric (natural and man-made features, suchas pavement edging). While the conversion to thenew GIS was occuring, the property appraiser pro-posed an interlocal agreement for the BCC and vari-ous municipalities to participate in the re-engineer-ing of the parcel layer. This would tie all propertiesto survey control coordinates using COGO and ob-tain the ortho-rectified photography and planimet-ric data. The agreement was reached between theBCC and the property appraiser in December1999. Two cities also signed interlocal agreementswith the property appraiser, and other cities ver-bally committed to sign agreements in 2000–2001.

This project is a major GIS undertaking in itsown right. There are many ways to implement amultipurpose GIS system, depending on the goalsand objectives of those who will use the informa-tion. However, many government jurisdictions haveimplemented GIS without a complete understand-

ing of all issues to properly implement the systemto serve current and future needs. In OrangeCounty, the property appraiser and the interlocalpartners established interlocal agreements for thesuccessful development of a spatially accurate GIS.The property appraiser was appointed as the projectmanagement agency to acquire or develop fourproducts: digital ortho-rectified photography, se-lected planimetric data, necessary survey control,and a seamless and accurate parcel and street map.To this end, the interlocal agreements establish thefunding sources and set up committees (policy,steering, and technical) to review and monitor theprocess and provide oversight.

Correcting HistoryThe State of Florida was originally surveyed basedon the rectangular survey system, with the excep-tion of Spanish land grants. The rectangular surveysystem is a grid of survey lines running east andwest (township lines) and north and south (rangelines), which are specifically numbered. Thesetownship and range lines were established in the1800s at six-mile intervals, thereby creating a gridof thirty-six square mile areas. Each township, orthirty-six square mile area, is further broken downinto its surveyed thirty-six sections or square miles,which again are broken down to quarter and quar-ter-quarter sections. This forms the basis of the landownership system from which the legal descriptionsof real estate are derived.

It should be pointed out that in states that usethe rectangular survey system, it is not possible todevelop a seamless and accurate parcel base withoutknowing the coordinate values of the section geo-detic control points (as shown in figure 4). It is of-ten necessary to locate quarter section control andother points to supplement the real world locationof property ownership boundaries. Many local gov-ernments have used the process of board digitizingpaper maps or scanning maps and performing digi-tizing on computer screens. However, the productgoing into the conversion process, as well as theconversion process itself, needs evaluation to fullysatisfy the quality and accuracy of the final product.The expected uses of the final product must also beevaluated, and the accuracy of the geometry and le-gal descriptions must be referenced to the geodeticcontrol to validate the positional accuracy in thereal world. If this is not the case, a floating mapmust be created with relative accuracy, the value ofwhich can vary greatly. If a GIS system is builton the floating map concept, then any layer or

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Figure 4Concept for a Multipurpose Land Information System

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theme that is developed, such as land use or transpor-tation, will have constant problems overlaying prop-erly, as they are not based on the same geodetic foun-dation.

In a floating map, the dimensions of the parcel orother lines will not accurately reflect the surveyedboundaries of those features. Using accurate GPS tocapture data in the field will also be problematic, asthe coordinates will not place the features where theyshould be in a map not based on survey control. Goodplanimetric data and digital ortho-rectified photogra-phy can assist in the placement process, but the geo-detic control coordinates, along with the surveyedproperty ownership geometry, is the most importantfeature for geometric accurate placement of parcel data(see figure 5).

Therefore, even though Orange County now has anenterprise GIS, to have a spatially accurate GIS thatcan be fully utilized requires the re-engineering of theparcel layer. To accomplish this, counties must haveadequate funding, professional management and per-sonnel resources, technical expertise, and commitment

from top management. The interlocal agreementsmust establish the funding mechanism, organizationalstructure, project management responsibility, timeline, and specific products and deliverables.

Getting the Job DoneIt was determined that the Orange County BCCand property appraiser would provide funding forthe entire project, with any municipal participationto offseting costs. The overall cost was estimated at$9.5 million, spread over five to six years. The in-ter-local agreements called for the property ap-praiser to focus on approximately 200 square milesa year to re-engineer. As each square mile is re-engi-neered, it would replace the old parcel data in theenterprise GIS database. All other agencies wouldadjust their layers to adhere to the survey controlpoints supplied to the property appraiser.

To accomplish this, the Orange County PropertyAppraiser’s Office was tasked with several steps, in-cluding securing the services of a photogrammetriccompany to obtain the ortho-rectified photography

Figure 5Geometric Placement of Parcel Data

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and selected planimetric data. The property ap-praiser would also secure the services of a surveycompany to locate all of the section and quarter sec-tion control points and obtain state plane coordi-nates on those points for input into the GIS. TheOrange County surveyor would act as the propertyappraiser’s agent in coordinating with the surveyfirm and acting as the property appraiser’s GISmanager. The property appraiser would hire eightcontract mapping personnel to create the re-engi-neered parcel data. The contract mappers wouldconsist of two professionally licensed surveyors, fourcartographers, and two annotation or data entrypersonnel. Each municipal interlocal partner wouldalso supply one mapper. An assembly line approachwas set up for the re-engineering process, with a se-nior staff cartographer assisting in supervising thecontract mappers. Each stage of the digital re-engi-neering process will be subject to quality controlbefore it moves along the assembly line. The ortho-rectified photography, planimetric data, and re-en-gineered parcel data would be inserted into the en-terprise GIS and replace the old information as itwas completed. The distinction between re-engi-neered and old data would be noted.

An important byproduct of this project would beto fulfill a long-awaited goal of the county surveyor.During the past twelve years, the surveyor was ableto create a three-mile-high precision grid of GPSpairs covering the entire county. However, the taskto locate all certified land corners had been slow go-ing and was performed on an as-needed basis. Hewas able to locate and obtain state plane coordi-nates on approximately three townships, or 108square miles, which is only one-ninth of the entirecounty. The interlocal agreement between theproperty appraiser and the BCC allowed the projectto be put on a fast track.

Approximately 200 square miles of the countyare surveyed annually. Where certified cornerrecords are not available, the best evidence of thecorner are obtained in the field and used as appro-priate in the re-engineering process. When geodeticcontrol for land corners or best evidence is not avail-able (lakes, swamps, and so on), the surveyors ob-tain control points from the nearest subdivision orright-of-way. When the project is completed, thecounty surveyor’s office will have a comprehensivelisting of certified corner records and their coordi-nate values. All future proposed plats would thenbe tied into the control network and provide digitaldata that would drop into the enterprise system,thus speeding up the development review process.

New ChallengesOne of the most technically challenging aspects ofthe project is placing the subdivisions and parcelboundaries using state plane coordinates on geo-detic reference points. It is one thing to write aseparate legal description or to survey one lot orsubdivision with bearings, angles, and distanceswithout regard as to the real world fit of thatboundary into the larger map. It is quite anotherchallenge to accurately place that boundary cor-rectly onto the overall map. Often, there are over-laps and gaps that need to be reconciled. Decisionsneed to be made based on original intent, errors inlegal descriptions, and insufficient or erroneous sur-vey information. These decisions require goodjudgement and common sense, as well as expertisein mapping real world parcel data. A consistent setof standards and procedures must be adhered to inmaking these decisions, as well as providing re-search to realize justified solutions.

Survey crews must locate the best evidence foundin the vicinity of the section and quarter sectioncorners where certified corner records do not exist.At times, they will find several markers in closeproximity to each other, requiring the propertyappraiser’s re-engineering team to check out thepoints in relation to the legal descriptions andplats, verifying the one(s) that provide the best fitin relation to placement of surrounding properties.It can also be challenging for the survey crews toobtain permission to enter properties. There alsoare times when no corner evidence exists (lakes), orthe corner no longer exists (removed due to con-struction). In these cases, the county requires surveycrews to locate points on the nearest subdivision(s)for retrofitting corners for section placement, whilereferring to adjoining sections for verification of aquality controlled fit.

The most challenging, yet satisfying, organiza-tional issue in the process was to bring differentagencies and political entities together to create aunited front to obtain the funding and support forthe project. The first three interlocal agreementstook a year to achieve, and created a great deal ofenthusiasm within the public and private sector inbeing able to provide a much needed, comprehen-sive, and easy to use GIS.

SummaryThe success of the new enterprise GIS and the par-cel re-engineering project is based on the fact it allworks in its most practical sense for local govern-ment and the public. As with any high profile

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project, it must be demonstrated that results can bedelivered on time and within budget. The firstproject, the creation of a user-friendly enterpriseGIS, was accomplished in eight months. The suc-cess of the conversion established the overall cred-ibility and leadership for the property appraiser andfocused on the need for a spatially accurate system.

Project deliverables were kept on schedule, withspecific delivery items that are of immediate use.Through interlocal agreements, acquisition ofdigital ortho-rectified photography, and plani-metric data for the re-engineering of the parcellayer, data redundancy and labor overhead areeliminated.