
John Callahan joined the staff of the Delaware Geological Survey as a Research Associate III in February 2008. Mr. Callahan brings to the DGS a combination scientific knowledge and technical skills. John's scientific background is in the areas of climatology and severe weather, atmospheric processes, surface hydrology, and physical geography. John also has significant experience in emerging web and database technologies, GIS/geospatial data analysis, and remote sensing. Currently, John is working on hydrologic processes, particularly related to tidal and stream flood inundation, weather related geohazards, sea level rise, environmental monitoring, and various projects in GIS and remote sensing. Another area of John's activities at DGS is the development and maintenance of DGS's public and internal web sites and data delivery mechanisms, such as web mapping services, DGS publication data downloads, and the Delaware DataMIL.
Before joining the DGS, John was the lead GIS Coordinator and primary technical support person for the University of Delaware. Housed within the Research Data Management Services (RDMS) group within the Office of Information Technologies, John built numerous web mapping applications, worked on a variety of geospatial and statistical analysis projects, and developed and taught many GIS-related and web development workshops. Previous to his employment at UD, Mr. Callahan worked as a GIS Consultant for Environmental Systems Research Institute (ESRI) in King of Prussia, PA and a Remote Sensing Specialist for Earth Satellite Corporation, in Rockville, MD.
John was one of of the original team members that developed and released the Delaware DataMIL in 2002. That year, Mr. Callahan (and his wife Tina Callahan) was fortunate enough to present DataMIL to 12,000+ attendees at the ESRI International User Conference. Throughout its history, DataMIL has received many postitive reviews and has been incorporated into the workflow of many state agencies, private consultants, and K-12 and higher education academic groups. For this work, John received the ESRI Special Achivement in GIS award in 2002 and the USGS John Wesley Powell Award in 2003. In addition to the DataMIL, John has contributed to several statewide GIS activities, including managing the Delaware Metadata Clearinghouse, chair of the GIS Conference committees in 2003 and 2004, and the recipient of the 2007 Delaware State Geographic Service Award.
Temple University, 1994, B.S., Physics
Temple University, 1994, B.S., Mathematics
DelDOT-TMC Weather Group (current)
Delaware Storm Reporter Advisory Group (current)
Delaware HAZUS User Group (current)
Delaware Geographic Service Award Committee (current)
Delaware Elevation Data Working Group (current)
GIS@UD User Group (current)
UD Web Developer Community (2006 - 2011)
Delaware Science Olympiad: Remote Sensing Event – Division C, 2003 – Present
Maintainer of the Delaware Geospatial Information Clearinghouse, 2001 - 2007
Chair and member of annual Delaware GIS Conference planning committee, 2001 - 2005
Recognition and Awards
Delaware State Geographic Service Award, 2007
USGS John Wesley Powell Award, 2003
ESRI Special Achievement in GIS (SAG) Award, 2002
Bates, A., Samoteskul, K., Callahan, J., Corbett, J., Kempton, W., Madsen, J., Shriver, G., Dvorak, M., Kenney, R., McCormack, R., Harris, K. Noel, L., and Firestone, J. (2012). Delaware Marine Spatial Planning: Offshore Wind Context. Final Report. Center for Carbon-free Power Integration.
Madsen, J., A. Bates, J. Callahan and J. Firestone (2011). Use of Geospatial Data in Planning for Offshore Wind Development. Geospatial Techniques for Managing Environmenal Resources. J. K. Thakur, Singh, S.K., Ramanathan, A., Prasad, M.B.K., Gossel, W. . Heidelberg, Germany, Springer and Capital publication.
William S. Schenck and John A. Callahan, "A New Delaware DataMIL", Digital Mapping Techniques '09 - Workshop Proceedings, USGS Open File Report 2010-1335. May 2009.
Angelia S. M. Vanderlaan, James J. Corbett, Shannon L. Green, John A. Callahan, Chengfeng Wang, Robert D. Kenney, Christopher T. Taggart, and Jeremy Firestone, "Probability and Mitigation of Vessel Encounters with North Atlantic Right Whales", Endangered Species Research, Vol 6, p. 273-285, March 2009.
Chengfeng Wang, John Callahan, and James Corbett. "Geospatial Modeling of Ship Traffic and Air Emissions", Proceedings of the ESRI International User Conference, June 2007.
Book chapter/Case Study: Co-edited, with staff at ESRI-Hong Kong, Chapter 4 in "Connecting Our World: GIS Web Services", ESRI Press, 2003.
Callahan, John A., Christina L. Callahan, Richard S. Sacher, Michael B. Mahaffie, William, S. Schenck, Shannon S. Bain, and Robert E. Rinehart, 2002, "The Delaware DataMIL: A Web-Based Mapping Collaboration" ArcNews, ESRI, Vol. 24, No. 2, Summer 2002. p. 18-19.
DeLiberty, Tracy L., and John A. Callahan, "Diurnal Variability of Satellite Derived Precipitable Water in the Amazon Basin", Proceedings of the 11th Conference on Satellite Meteorology and Oceanography, American Meteorological Society. Madison, Wisconsin, Oct. 15-18, 2001. p. 196-199.
Deliberty, T.L., J.A. Callahan, A.R. Guillory, and G.J. Jedlovec, 2000: A Regional Scale Assessment of Satellite-Derived Precipitable Water in the Amazon Basin. Preprints, 10th Conference on Satellite Meteorology and Oceanography, Long Beach, CA, Amer. Meteor. Soc., 414-417.
Willis, Dawn, Jacqui Wilson, and John Callahan, 1999; Teaching Geography with Technology: A Special Summer Institute for Delaware State Teachers, Proceedings of the 84th Annual Meeting of the National Council of Geographic Education, Boston, MA, November 3 – 6, 1999.
DeLiberty, Tracy L. and John A. Callahan, 1998; Mesoscale Moisture Variations Associated With Cold Surges In Southern Brazil, Proceedings of the 23rd Conference on Hurricanes and Tropical Meteorology, Dallas, TX, January 1—15, 1999.
First State Geology Articles
"DGS Unveils New Website and Web-Mapping Services", First State Geology, Delaware Geological Survey, Winter 2011, p. 2.
"Prototype Coastal Flood Monitoring System for Delaware", First State Geology, Delaware Geological Survey, Winter 2011, p. 3.
"DataMIL Gets a New Look", First State Geology, Delaware Geological Survey, Winter 2011, p. 4.
"Delaware: A National Map Pilot Project", First State Geology, Delaware Geological Survey, Vol 20, No. 1, Winter 2002. p. 2.
"The Delaware Coastal Flood Monitoring System", Delaware Estuary Science and Environmental Summit, Cape May, NJ, January 2013.
"The Delaware Geologic Information Resource (DGIR)", (poster) Delaware Estuary Science and Environmental Summit, Cape May, NJ, January 2013.
"A Coastal Flood Monitoring System for Delaware", Association of American Geographers (AAG) Annual Meeting, New York, April 2012.
"A Web-based System for the Delivery of Hydrogeologic Data", Delaware Estuary Science and Environmental Summit, Feb 2011
"A Prototype Coastal Flood Monitoring System for Delaware", Delaware Estuary Science and Environmental Summit, Feb 2011
"Development of a GIS Database in a Marine Spatial Planning Context for Offshore Wind Power in Delaware", Delaware Estuary Science and Environmental Summit, Feb 2011
"Opening Geospatial Information: Trends and Technology", plenary presentation for UD Geospatial Research Day, Nov 2009
"A New Campus Mapping Initiative at the University of Delaware", UD Building and Maps Team, Newark, DE, June 2008
Google Maps Technical Workshop, Delaware State 2007 Conference, June 2007
Northeast Map Organization (NEMO) Annual conference, Guest panelist for "GIS Portals and Web Mapping Services", New York, NY, June 2007
Developed and taught "The Hitchhikers Guide to the Galaxy of Geospatial Metadata", workshop for the Delaware State GIS Conference, June 2006
"Introduction to GIS", Two-day workshop to College of Marine and Earth Science, Lewes, DE, January 2006
Workshop on "Introduction to ArcIMS and WMS Web Mapping Services: What Are They and How Can I Use Them?", Delaware State GIS 2004 Conference, April 2004
"The University of Delaware: A Self-Sustaining GIS Community", co-presented with Christina Callahan, 2003 ESRI Education User Conference, San Diego, CA, July 2003
Presented "The Delaware DataMIL: Delaware's Geography Network and contribution toward The National Map", University Consortium of Geographic Information Science (UCGIS) Winter Meeting, Presentations to Congress, February, 2003
Presented "Status of Geographic Information Systems in Delaware", Center for Remote Sensing Seminar Series, University of Delaware, Newark, DE, November 2002
"Internet Mapping using ArcIMS", Two-day seminar, USGS Mid-Continent Mapping Center, USGS Central Region, Rolla, MO, August 2002
"The Delaware DataMIL", ESRI User Conference plenary (12,000+ attendees), San Diego, CA, July 2002
Plenary presentation, "The Delaware Data Mapping and Integration Laboratory (DataMIL)” at the Delaware State GIS Conference, Rehoboth Beach, DE, April 18, 2002.
Presented and demonstrated "The Delaware Data Mapping and Integration Laboratory (DataMIL)" during the plenary session at the ESRI Federal User Conference, Washington, D.C., April 3, 2002.
Presented "The Delaware Data Mapping and Integration Laboratory (DataMIL)" briefing to the USGS Cooperative Topographic Mapping (CTM) Group, USGS Headquarters, Washington, D.C., March 20, 2002.
Presented “The Delaware Data Mapping and Integration Laboratory (DataMIL)” and participated in the USGS The National Map Developer’s Workshop, EROS Data Center, USGS, Sioux Falls, SD, March 6-8, 2002.
Presented "The State of GIS in Delaware", University of Delaware, Department of Geography Seminar Series, February 15, 2002.
Co-Developed and co-taught "GIS Career Student Workshop", University of Delaware, November 2001
Co-Developed and co-taught workshop "Integrating GPS and GIS" 1-day workshop, Delaware Geographic Alliance, Fifer Middle School, October, 2001.
Co-Developed and co-taught 3-day Geography and Technology workshop, Delaware Geographic Alliance Technology Institute, University of Delaware, July 23 – 25, 2001.
Presented "Geography and Technology in the Classroom with special focus on the ArcView Geographic Information System" as part of the Advanced Teacher Institute held at the University of Delaware. Organized by the Delaware Geographic Alliance (DGA), July 1998.
Thesis defense, "Estimation of Precipitable Water Fields Over Amazonia Using GOES Imagery”, University of Delaware, Department of Geography Seminar Series, May 1998.
"Geography and Technology with special focus on the ArcView Geographic Information System", St. Mark’s High School, Delaware Geographic Alliance (DGA), April 1998.
"Estimating Precipitable Water Fields Over the Amazon Basin Using GOES Imagery" at the Association of American Geographers (AAG) Annual Meeting, Boston, MA, March 1998
"A Regional-Scale Investigation of the Hydrologic Cycle in Amazonia Using a GIS" at the University Consortium for Geographic Information Science (UCGIS) Annual Retreat and Assembly, Bar Harbor, ME, June 1997
"Solar Radiation Modeling in the Coterminous United States" at the University Consortium for Geographic Information Science (UCGIS) Annual Retreat and Assembly, Bar Harbor, ME, June 1997
"PW Estimation in the Amazon River Basin from Remotely Sensed Data" at the Association of American Geographers Annual Meeting, Fort Worth, TX, March 1997
"PW Estimation in the Amazon River Basin from Remotely Sensed Data" at the Association of American Geographers Middle-States Division Annual Meeting, Philadelphia, PA, October 1996
Guest lecturer in numerous courses at UD, including Advanced GIS, Introduction to GIS, GIS in Public Policy, GIS in Natural Resource Management, and Introduction to Data Analysis
Co-Principal Investigator, "A Climate Change Analysis for Delaware and the Delaware Bay Estuary", Funding from Delaware National Estuarine Research Reserve (DNERR), March 2012 - March 2013.
Co-Principal Investigator, "Modeling Tsunami Inundation and Assessing Tsunami Hazards for the US East Coast", Funding by National Tsunami Hazard Mitigation Program (NTHMP), NOAA, August 2010 – July 2013.
Co-Principal Investigator, "Delaware Geological Survey Node Development for Inclusion and Participation in the United States Geoscience Information Network (USGIN)", Funding from the National Science Foundation via the Arizona Geological Survey, June 2012 - December 2012.
Technical lead for the Delaware Geologic Information Repository (DGIR)
Principal Investigator, "A Web-Delivered Application for Hydrogeologic Data", Funding from Delaware Department of Natural Resources and Environmental Control, Water Supply Section, July 2010 – December 2011.
Co-Principal Investigator, "Expansion of the Coastal Flood Monitoring System for Delaware", Funding from Delaware Department of Natural Resources and Environmental Control, Coastal Programs, January 2011 – September 2012.
Co-Principal Investigator, "Offshore Wind Power for Delaware in a Marine Spatial Planning Context", Delaware SeaGrant Program, February 2011 - February 2012.
Co-Principal Investigator, "DGS Digital Image Metadata", USGS National Geological and Geophysical Data Preservation Program, July 2009 – June 2010.
Co-Principal Investigator, "A Prototype Coastal Flood Monitoring System for Delaware", Joint funding from Delaware NSF EPSCoR and Delaware Department of Environmental Control, July 2009 – July 2010.
Co-Principal Investigator, "NSDI Cooperative Agreements Program, Category 3: Clearinghouse Integration with Web Mapping Services", October 2002 – September 2003.
Co-Principal Investigator, "The USGS National Map/Delaware Framework DataMIL Project", USGS Title VII Funding Initiatives, August 2001 – December 2002.
Co-Collaborator, "A University Teaching Laboratory for Geographic Information Science", University of Delaware, College of Arts and Sciences, September 2001.
Courses Taught
- FREC480: GIS in Natural Resource Management
- GEOG152: Climate and Life
- GEOG220: Meteorology
- GEOG250: Computer Methods in Geography
- Teaching Geography with Technology: A Special Summer Institute for Delaware State Teachers



First State Geology has been the newsletter of DGS for over 25 years.


