Castle Consulting was founded in January 1992. Among the consulting services the firm offers are these:

• The components and functions of a GIS,
• The profitable use of the technology in various real estate activities (e.g., market research, trade area analysis, brokerage, appraisal, acquisition due diligence, asset management, presentation graphics), and
• Case studies on real estate organizations already successfully using GIS;

• Software vendors,
• Data sources (e.g., property-specific, socioeconomic, regulatory, imagery),
• Hardware, operating systems, communication networks,
• Administrative structures, types and sources of personnel, and so on;

Castle Consulting's past and current clients include:

• CB Commercial, Torrence, California
• MetLife Realty Group, Inc. White Plains, New York
• Edward S. Gordon Company, Inc., New York, New York
• Staubach Retail Services, Dallas, Texas
• The Gap, San Bruno, California
• U.S. West Communications, Inc., Denver, Colorado
• TELERES, Dayton, Ohio
• Bruton Information Inc., Dallas, Texas
• Pizzuti Development, Inc., Columbus, Ohio
• The Swearingen Company, Dallas, Texas
• Environmental Risk Information & Imaging Services (ERIIS), Herndon, Virginia
• Terranomics, San Francisco, California

• Fannie Mae, Washington, D.C.
• Land Information Alberta, Edmonton, Alberta
• Real Estate Board of Greater Vancouver, Vancouver, British Columbia
• Metropolitan Transportation Commission (MTC), Oakland, California

• The Appraisal Institute
• American Society of Real Estate Counsellors (ASREC)
• International Association for Corporate and Office Real Estate (NACORE)
• National Council of Real Estate Investment Fiduciaries (NCREIF)
• International Association of Assessing Officers (IAAO)
• Urban and Regional Information Systems Association (URISA)

The founder and chief executive officer of Castle Consulting is Gilbert Castle. Mr. Castle has been a GIS consultant since 1978. Prior to starting Castle Consulting, he was a Regional Director of the Roulac Group of Deloitte & Touche (the real estate consulting division of the Big Five accounting firm). Mr. Castle is a Past President of the Urban and Regional Information Systems Association, North America's largest and oldest professional society for GIS practitioners. Mr. Castle has more than 150 publications and conference presentations to his credit, primarily on applied computer technology in land use decisions. For example, he is the overall editor for the 400 page book Profiting from a Geographic Information System, the seminal text on GIS applications in the private sector, and GIS in Real Estate, jointly published by the Appraisal Institute and GIS World, Inc. He also writes the real estate column for Business Geographics magazine. Mr. Castle has lectured at numerous universities on applied GIS technology, including the Massachusetts Institute of Technology, the University of Pennsylvania, Stanford University, and the University of California at Berkeley. He holds a Bachelor of Science degree in Economics, Cum Laude, from Harvard University, and a Master of City Planning degree from the University of Pennsylvania.