Feature: Even in a Recession, Aerial Mapping Continues to Grow in Many Ways
By Tina Cary, PhD
A number of interesting developments come to my mind when I think about the state of the aerial mapping industry as we transition from the first decade of the third millennium to the second.
The cell phones now carried by 87 percent of Americans are GPS-enabled, driven by a government requirement that carriers be able to report the locations associated with emergency calls. The Public Safety Answering Points that receive those calls use some combination of topographic, planimetric, and image data; the life-or-death accuracy requirements make map updating an ongoing demand.
Consumers have been introduced to maps and image data by MapQuest
; personal navigation devices (a popular electronic gadget for Christmas 2008) and smart phones (13 percent of the cell phone market) now provide people with access to maps and image data while out and about, not just sitting at a desk.
The incorporation of location in social networking has become popular as the use of social media has grown. While people sharing their whereabouts with friends in such applications as Brightkite
, and Loopt
is not a component of the aerial imaging market, I see it as a relevant development. It indicates that people continue to be driven to answer the age-old questions, “Where am I?” and “What is my place in the world?”
Another example of mapping by and for “regular people” is OpenStreetMap
, which describes itself on its website as “a free editable map of the whole world.” Its data are freely available for anyone to use without restriction, in contrast to legal or technical restrictions associated with most maps. Sources of data include handheld GPS devices, aerial photography, other free and unrestricted sources, and local knowledge.
While such crowdsourcing may sound like a prescription for chaotic and useless maps, the wiki capability for anyone to edit the map works as well here as it does on the more-familiar wikipedia, with the results tending to be continuously improved. OpenStreetMap had 300,000,000 nodes at the beginning of 2009 and 500,000,000 nodes at the end of the year. Anyone anywhere can contribute to this project, and people do: in 2009, OpenStreetMap doubled the number of registered users to 200,000.
As with social networking, this development outside the aerial mapping industry shows that the desire to know “Where am I?” will never be sated. It also illustrates that consumer expectations always grow; people expect both greater availability and greater accuracy of map data, and this bodes well for the aerial mapping market.
A key motivation for maps and mapping is defense needs. The U.S. Army Corps of Engineer’s Army Geospatial Center
(AGC) supports the needs of the U.S. Army and Department of Defense to visualize and analyze battlefield terrain and environmental information. Three-dimensional visualization helps people understand and communicate in ways that flat maps do not. As part of its support, AGC has maintained product information about commercial terrain visualization software for several years. Tools include real-time visual simulation software and geographic information systems with 3D rendering and analysis. Technologies developed for the fast-growing gaming industry are used to enable 3D visualization. The most recent Survey of Terrain Visualization Software, dated September 17, 2008, contains information about more than 500 products, including commercial games that use real-world data.
And where does digital topographic data come from today? How we gather data to answer the question “Where am I?” now includes land surveying, mobile mapping, and planes and satellites. Land surveying continues to provide essential control for topographic mapping. Mobile mapping offers accuracies in the range of millimeters, appropriate for highway projects in particular. While mobile mapping has been commercially available for a few years, it saw significant uptake in 2009. Mobile mapping is more complementary than competitive with aerial mapping.
Film cameras see less and less use, as requests for airborne data for mapping purposes now often require that the data be collected digitally. Manufacturers introduce new digital aerial cameras and airborne lidar sensors frequently, and geometric accuracy continually improves. Two-foot contours are a common deliverable today; only a decade ago technology did not provide a cost-effective way to routinely deliver such detail. Airborne digital cameras were purchased at a rate approaching one a week in 2009, an amazing level of investment in aerial mapping given the state of the global economy.
The number of airborne lidar sensors in operation has grown about 20 percent a year on average. Sensors have become lighter in weight and more compact as pulse rates, scan rates, and point densities have increased. Multi-pulse lidar technology enables a plane to fly higher and collect data more efficiently than traditional lidar systems that could only manage one pulse in the air at a time. Multi-pulse technology is in a relatively early phase on the adoption curve. The weight of lidar systems is now low enough that lidar can be included on remotely piloted vehicles. This capability has value in battlefield conditions, enabling the collection of current topographic data.
The growth in number of lidar systems does not mean the market is getting saturated. Demand for lidar data is increasing faster than the supply. This is a consequence of growing customer expectations, good news for the aerial mapping market.
Currently, processing lidar data continues to present technical challenges that provide fertile ground for research. The volume of lidar data tests the limits of storage capacity for data collection and processing, then it presents additional challenges in delivering the data to customers. Efficient extraction of breaklines is also an opportunity for research and development.
Like airborne data that collected from satellites has ever more spatial detail, so satellite data available today matches the quality of data collected from aircraft a decade ago. The idea that a satellite hundreds of kilometers away can measure an area as small as 50 centimeters is amazing. The earthquake in Haiti the evening of January 12, 2010 has highlighted another advance: the ability to deliver satellite data rapidly in a non-military application. GeoEye
both had post-quake imagery collected, processed, analyzed, and posted on the internet by the morning of January 14.
Another key driver (besides defense) for aerial mapping is economic. From earliest times, exploration and mapping have been linked to resource exploitation. Today, resource mapping also includes monitoring and managing resources for sustainable use. While individual development projects require the kind of high-resolution data collected from aircraft discussed above, large-scale resource mapping is currently more likely to use coarser-resolution satellite data than aerial mapping.
Topographic data for the Earth—from 56° S to 60° N—were collected by the Shuttle Radar Topography Mission during an 11-day mission in February 2000. The data have been processed and made available online for free. The Version 2 dataset, released in late 2005, is the result of substantial editing by the National Geospatial Intelligence Agency
; it exhibits well-defined water bodies and coastlines. The data have 90-meter resolution, with 30-meter resolution available for the United States. The fact that the data are free might sound like competition for aerial mapping, but its 30-meter or 90-meter accuracy serves to stimulate the market for higher-resolution topographic data. While satellites today collect radar data with a resolution of one meter, projects requiring centimeter accuracy will continue to turn to aerial acquisition.
With the collection of digital data and its delivery to clients, workflows today can be all digital. Algorithms are being implemented to automatically extract surface models from digital imagery. Development of feature extraction algorithms continues as a fertile area for research. Data fusion is another growth area, because mobile mappers and airborne lidar and digital cameras each contribute different information to a mapping project. Figuring out how to integrate or fuse them appropriately makes for an exciting research frontier.
In assessing aerial mapping at the beginning of the second decade of the third millennium, we have seen that the human need to know “Where am I?” continues, unlikely ever to be sated. How we gain the answer to that question and how accurately and precisely we can answer it have changed and will continue to change. In addition, how we document those answers, with whom we share them, and how quickly we share them are changing as well.
Dr. Tina Cary is founder and president of Cary and Associates, a market research firm in Longmont, CO specializing in GIS, remote sensing, photogrammetry, surveying, and GPS.
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