Disaster geomatics.

The destruction and carnage caused by Hurricane Katrina, and the resulting tears, chaos, squalor and terror-especially in New Orleans-will not be forgotten for a long time. Many of Katrina's effects, such as fluctuations in the price of gasoline and other significant economic and social impacts, continue to be short-term reminders of the disaster's far-reaching influence. It will figure in the congressional elections of 2006 and possibly even in the presidential election of '08. But this column is not about any of those outcomes. Instead, this is my opportunity to ponder how surveying and mapping may have supported disaster preparedness before and during the storm, and how they might be involved after the storm. This is not written to second-guess the specific geomatics activities that might or might not have been done with respect to Katrina. Rather, it is my intent to help surveyors, both public and private, appreciate the significant role surveying and mapping has in events such as this.

Dauphin Island, Ala. Map views of post-storm difference grids for Hurricanes Ivan (A) and Katrina (B), and vertical photography of the same location (C). The lidar images show elevation gains (green) and losses (red). Image courtesy of NOAA/Department of Commerce.

Before the Storm

For emergency preparedness in New Orleans, it should be obvious that basic information about the lay of the land, especially critical elevations of the low points of the crests of the dams and levees and how they relate to tide levels, is important. This includes the contours of the land within the levees and the location of structures and high points. Maps showing the layout of the utilities including locations of manholes, valves and valve vaults, transformers and switching yards are a necessary part of disaster preparedness and management. So are details of transportation networks such as roads, highways, railways, pipelines and canals. Other possible preparations from a mapping front would have included maps of critical facilities such as clinics, emergency rooms, operating rooms, nursing homes and elderly care facilities, as well as schools, prisons, jails and other institutional facilities where people are housed. As the media continues to report on New Orleans and as more information about the city becomes available, it will be interesting to find out how and what mapping data was used to assist in the location of sources for supplying building materials, food, bottled water, clothes and blankets. Additionally, if it hadn’t been done before, there will unquestionably be an interest in recording such things as square footage and elevation of each critical structure’s floors, location of gas, water and electric meters, and the location of residents requiring life- or health-critical electricity, personal care or medication.


Not only government agencies but such organizations as utilities, transportation companies and a wide variety of disaster cleanup organizations may have had an interest in maps of evacuation routes, along with alternate routes that came into play depending on the type of disaster and the estimated level of destruction to transportation networks. In this case, not only did encroachment of floodwaters have to be recognized, but the possibilities of bridge destruction, live power lines on roads, and fallen trees and other debris. Road clearing crews, search and rescue teams and disaster assistance teams bringing temporary shelter, food and clothing need these same maps to find their way in to the affected areas. Not only do these types of maps and spatially based information need to exist, they need to be supported by an infrastructure that enables quick updates.

During the Storm

During the storm and subsequent inundation of the land, weather satellites and various other sensors provided space imagery of Louisiana, Mississippi and Alabama for visible spectrum and imagery. As soon as the winds died down, many aircraft were launched to take still and video photography. Measurements of the tides and comparisons with other water levels in the inundated areas, as well as other bodies of water such as Lake Pontchartrain, were being measured by direct and indirect means by many agencies, including the U.S. Geological Survey and the U.S. Army Corps of Engineers.

After the Storm

The effects of Katrina will continue to influence geomatics activities for years. During the tumultuous week after the storm, major television network news reports indicated that “secret” National Geospatial Intelligence Agency (NGA) technology was being used to detect and map possible survivors of the flooding. Locating survivors was difficult because they were inside attic spaces or otherwise invisible to the naked eye or visible spectrum technology. The news reports led me to believe that spectra other than visible light (perhaps thermal energy) was being used to detect hidden survivors. And the initial mapping of the aftermath included information that helped in evaluation of the types and quantities of hazardous material spills.


Some geomatics professionals volunteered their skills and knowledge to help with the relief effort after the storm. An unprecedented number of applicants applied to be GISCorps volunteers through The Urban and Regional Information Systems Association (URISA) and asked to be deployed to areas affected by Hurricane Katrina. With many rescuers unfamiliar with the area’s geography, and with even locals confused because of the lack of street signs and destruction or inundation of familiar landmarks, the GISCorps volunteers took calls from survivors and spotters describing their locations. The volunteers turned these locations into GPS coordinates; rescuers could then navigate to these coordinates to perform their missions of mercy. News reports also indicated that in the process of locating the living, the dead were also encountered. But because of the emphasis on saving lives, GPS was used to catalog the locations of the corpses for later collection. Similarly, GPS was used to dispatch and track the missions and results of search and rescue teams as they began house-to-house searches for the living (human and animal) as well as the dead.


Additional damage caused by Katrina will require different mapping solutions. For example, television news reports showed sources of bubbling gas next to many of the inundated houses. It turned out these were due to broken natural gas lines. Locating and cataloging these breaks and other effects of the damage is a huge task; depending on the type of damage, different players will have to get involved to resolve the issues. In this case, it will be interesting to find out whether this post-Katrina mapping was performed by private contractors, government agencies or the real owners—the gas utility companies. With so much mud and other types of overwash on much of the land, utilities and other infrastructure providers will have to invest in significant mapping activity on the changed landscape to find the facilities needed for service repair, such as valves, transformers and utility meters.


The activities relating to razing huge areas of residences and businesses can have impact on property boundaries. Will efforts be taken to memorialize the position of the existent corners? Will new monumentation be set to enable recovery of lines now marked by monuments? What, especially in the soft, wet soil of New Orleans, is the appropriate monumentation to be used? Based on this experience, will new regulations be promulgated regarding development in potentially hazardous areas? Will such development be prevented or more stringently regulated? This doesn’t just apply to the obviously low-lying areas in New Orleans, but also to the swamps, islands and related marine environments that often are the first line of defense against a hurricane.


Surveying and mapping services are critical tools in preparing for, anticipating, responding during, and responding after disasters of any type. Perhaps we should be making our skills, abilities and technologies known to those who plan for and respond to disasters.

What has your role been in preparing for or responding to this disaster or other disasters? What might we have learned from Katrina to help us as surveyors and mappers provide guidance, data and information to disaster responders? Write to us at hohnerl@bnpmedia.com and jensenk@bnpmedia.com.