Patrick Callahan

Experience

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  Aerial Data Reduction, Inc

  Aug 1989 - Mar 1994

  Quality Control Data Editor

  Senior Cartographer - 1991 - 1994GIS Data Editor - 1989 - 1991

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  Loudoun County

  Mar 1994 - Jan 2000

  Senior GIS Analyst

  Office of Mapping and Geographic InformationSenior GIS Analyst - 1997 to 2000Cartographer - 1994 to 1997

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  WSSC

  Jan 2000 - Apr 2003

  Senior GIS Analyst

  Provided GIS support, analysis, and mapping for the Commission using ArcGIS 8.x and Arcview 3.x. Lead technical support for WSSC intranet mapping program called WebMap and for the WSSC internet mapping program for external users called WSSC Engineering Records/Information. Created a new Capital Improvement Project Mapping program for the Budget Department so projects could be entered in from several GIS users and be available for viewing Commission wide. Developed for the Mapping Unit a process in ArcGIS to download property plats from the web, register the raster plat file into the appropriate coordinate system, and then digitize the data into a shape file. Created an ArcMap tool for georeferencing raster images from Maryland State Plane NAD27, and WSSC coordinates to NAD83 coordinates. Moderator for Arc/Info, ArcGIS, Arcview and WebMap discussions on the Decision Information Technologies forum internal web site. Show less

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  Prince George's County Office of Information Technology

  Apr 2003 - now

  GIS Manager

  GIS Manager 2005 - PresentSenior GIS Analyst 2003 - 2005Created and managed 2 Enterprise Geodatabases that are the central repository for all County spatial data. Instrumental in creating a disaster recovery planning for the GIS division by creating and managing a third Geodatabase which could failover if one of the two Enterprise Geodatabases failed. Spatial data updates to all three Geodatabases were performed automatically to ensure data was replicated across the Enterprise. Created a data capture program in ArcGIS 9.x and ArcGIS 10.x to capture all Storm Water infrastructure in the County and provided output of Spatial and Non-Spatial data to be delievered to the National Pollutant Discharge Elimination Program (MPDES). Programmed several automated applications to take non-spatial data, geocode the records and produce spatial data to the Enterprise Geodatabases. Lead Cartographer, providing mapping and analysis to 35 County Agencies. Show less