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The history of Prince William County’s GIS (Geographic Information Systems) can be traced back to 1984 as part of a recommendation to unite all existing mapping resources in the County. Within 3 years, they had purchases ESRI software and received delivery of traditional hardcopy and digital files from ortho photography and the County then began creating the anchor layers for its GIS system which were a street centerline network and parcels. Over 150 additional layers have been added throughout the 26 year history of the County’s GIS, all building from the initial data delivery in 1987.


In the late 1990’s and early 2000, PWC GIS began utilizing technology for publishing data on the Internet. It became apparent that this was the most effective and cost efficient way to distribute accurate GIS products and services. Since that time, PWC GIS has deployed 13 intra/internet mapping applications, along with 17 custom desktop applications and over 21 custom desktop tools for GIS users.



·         First began in 1984 with a study of Land Information Systems in PWC

·         Obtained base data that include 17 geodetic monuments and digital land base

·         In 1987 purchased ESRI ArcInfo software suite

·         In 1988 staff began digitizing parcel layer and developed street centerline network

·         Converted from taxmap# to GPIN number in 1994

·         First Internet Mapping Service (County Mapper) deployed in 1998

·         Converted from International feet to US Survey foot in 2002

·         Converted from coverage format to versioned geodatabase format 2006

·         Established over 156 data layers in 26 years




Prince William County GIS is committed to developing GIS desktop applications, custom desktop tools, internet and web services to support the general public and user agencies with their business processes and decisions that impact the County Government. There are multiple ways that promote interoperability with the enterprise GIS and are connected to both GIS contributors and consumers.


Types of Services

·         Create and maintain the core GIS data layers and special interest GIS data layers

·         Create and maintain Interactive Mapping Applications for the desktop and web

·         Create standard and custom map products

·         Provide publications related to geospatial information

·         Resource for land records research

·         Delivery of digital data

·         Address validation and assignment

·         Countywide technical support for GIS users

·         Exploit the use of GIS in PWC for analysis and business decisions


Ways GIS is used and supported in PWC

·         Development Services – Tidemark Advantage Land Permitting System

·         Public Safety Communications – E911 Response

·         Fire and Rescue – Response Time analysis, incident mapping

·         Police – Search and Rescue, Incident mapping, crime analysis

·         Emergency Operations – Pre-incident Planning

·         Demographics – Population Trends, Redistricting

·         Transportation – Transportation Planning

·         Planning – Overlay and analysis

·         Real Estate Assessments – Trends

·         Environmental Services – Storm Water Management, Gypsy Moth Mosquito Control




PWC GIS staffing positions classifications consist of GIS database administrator, GIS System Developers, GIS Analysts I & IIs as well as management positions. These staff members are distributed among two teams, GIS Data Services Team and GIS Services and Solutions Team. GDS is responsible for development and maintenance of all new and existing data layers for the enterprise GIS, as well as, addressing and frontline customer services. The GSS is responsible for the development and maintenance of all GIS related desktop/web applications, workflow processes and GIS technical support. There are six additional agencies who have GIS Analyst position within their organization to perform agency specific tasks (ie. Planning, Public Works, Police, etc.)





Prince William County uses the ESRI Software Suite as the standard application for our GIS environment. There is a mix of ArcInfo and ArcView users throughout the PWC GIS community. The core GIS function resides in the Department of Information Technology. Other agencies may have imbedded GIS staff or designated classifications that perform agency specific GIS tasks.


The enterprise production environment consists of 2 HP Itanium Servers (production and failover). The relational database environment is Oracle 11g. Web applications are using ArcServer Enterprise Advanced, Flex and Silverlight.


Prince William County is currently using ArcGIS 10 for all clients and servers. Various extensions are utilized by agencies, depending on their business needs. Some examples are:

·         ESRI Workflow Manager 10

·         ESRI Data Reviewer 10

·         ArcMobile and ArcPAD

·         ESRI Spatial Analyst  and 3D Analyst 10

·         Pictometry


The County’s Enterprise GIS data is stored as one (1) Enterprise Geodatabase containing 9 feature datasets consisting of 68 separate feature classes. Additionally, there are:

·         20 Raster Mosaics – Digital imagery ranges from 1998 to 2011

·         Pictometry Oblique Imagery available for internal use only

·         110 Standalone SDE layers

·         17 custom tools and 21 custom desktop/web applications supported by GIS staff.



·         ESRI Special Achievement in GIS Award – 2007

·         Prince William County Continuous Quality Improvement Gold Award – 2007

·         County Executive Award Winner – 2007

·         URISA Exemplary Systems in Government, Single Process Winner - 2007




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