The Digital Earth:
Understanding
our planet in the 21st
Century
by Al Gore
Given at the
California Science Center, Los Angeles, California, on January 31, 1998.
A new wave of
technological innovation is allowing us to capture, store, process and display
an unprecedented amount of information about our planet and a wide variety of
environmental and cultural phenomena. Much of this information will be
"georeferenced" - that is, it will refer to some specific place on
the Earth’s surface.
The hard part of
taking advantage of this flood of geospatial information will be making sense
of it. - turning raw data into understandable information. Today, we often find
that we have more information than we know what to do with. The Landsat
program, designed to help us understand the global environment, is a good
example. The Landsat satellite is capable of taking a complete photograph of
the entire planet every two weeks, and it’s been collecting data for more than
20 years. In spite of the great need for that information, the vast majority of
those images have never fired a single neuron in a single human brain. Instead,
they are stored in electronic silos of data. We used to have an agricultural
policy where we stored grain in Midwestern silos and let it rot while millions
of people starved to death. Now we have an insatiable hunger for knowledge. Yet
a great deal of data remains unused.
Part of the problem
has to do with the way information is displayed. Someone once said that if we
tried to describe the human brain in computer terms, it looks as if we have a
low bit rate, but very high resolution. For example, researchers have long
known that we have trouble remembering more than seven pieces of data in our
short-term memory. That’s a low bit rate. On the other hand, we can absorb
billions of bits of information instantly if they are arrayed in a recognizable
pattern within which each bit gains meaning in relation to all the others — a
human face, or a galaxy of stars.
The tools we have
most commonly used to interact with data, such as the "desktop
metaphor" employed by the Macintosh and Windows operating systems, are not
really suited to this new challenge. I believe we need a "Digital
Earth". A multi-resolution, three-dimensional representation of the
planet, into which we can embed vast quantities of geo-referenced data.
Imagine, for
example, a young child going to a Digital Earth exhibit at a local museum.
After donning a head-mounted display, she sees Earth as it appears from space.
Using a data glove, she zooms in, using higher and higher levels of resolution,
to see continents, then regions, countries, cities, and finally individual
houses, trees, and other natural and man-made objects. Having found an area of
the planet she is interested in exploring, she takes the equivalent of a
"magic carpet ride" through a 3-D visualization of the terrain. Of
course, terrain is only one of the many kinds of data with which she can
interact. Using the systems’ voice recognition capabilities, she is able to
request information on land cover, distribution of plant and animal species,
real-time weather, roads, political boundaries, and population. She can also
visualize the environmental information that she and other students all over
the world have collected as part of the GLOBE project. This information can be
seamlessly fused with the digital map or terrain data. She can get more
information on many of the objects she sees by using her data glove to click on
a hyperlink. To prepare for her family’s vacation to Yellowstone National Park,
for example, she plans the perfect hike to the geysers, bison, and bighorn
sheep that she has just read about. In fact, she can follow the trail visually
from start to finish before she ever leaves the museum in her hometown.
She is not limited to
moving through space, but can also travel through time. After taking a virtual
field-trip to Paris to visit the Louvre, she moves backward in time to learn
about French history, perusing digitized maps overlaid on the surface of the
Digital Earth, newsreel footage, oral history, newspapers and other primary
sources. She sends some of this information to her personal e-mail address to
study later. The time-line, which stretches off in the distance, can be set for
days, years, centuries, or even geological epochs, for those occasions when she
wants to learn more about dinosaurs.
Obviously, no one
organization in government, industry or academia could undertake such a
project. Like the World Wide Web, it would require the grassroots efforts of
hundreds of thousands of individuals, companies, university researchers, and
government organizations. Although some of the data for the Digital Earth would
be in the public domain, it might also become a digital marketplace for
companies selling a vast array of commercial imagery and value-added
information services. It could also become a "collaboratory"-- a
laboratory without walls — for research scientists seeking to understand the
complex interaction between humanity and our environment.
Technologies
needed for a Digital Earth
Although this
scenario may seem like science fiction, most of the technologies and
capabilities that would be required to build a Digital Earth are either here or
under development. Of course, the capabilities of a Digital Earth will continue
to evolve over time. What we will be able to do in 2005 will look primitive
compared to the Digital Earth of the year 2020. Below are just a few of the
technologies that are needed:
Computational
Science: Until the advent
of computers, both experimental and theoretical ways of creating knowledge have
been limited. Many of the phenomena that experimental scientists would like to
study are too hard to observe - they may be too small or too large, too fast or
too slow, occurring in a billionth of a second or over a billion years. Pure
theory, on the other hand, cannot predict the outcomes of complex natural
phenomena like thunderstorms or air flows over airplanes. But with high-speed
computers as a new tool, we can simulate phenomena that are impossible to observe,
and simultaneously better understand data from observations. In this way,
computational science allows us to overcome the limitations of both
experimental and theoretical science. Modeling and simulation will give us new
insights into the data that we are collecting about our planet.
Mass Storage: The
Digital Earth will require storing quadrillions of bytes of information. Later
this year, NASAs Mission to Planet Earth
program will generate a terrabyte of information each day. Fortunately, we are
continuing to make dramatic improvements in this area.
Satellite
Imagery: The Administration
has licensed commercial satellites systems that will provide 1-meter resolution
imagery beginning in early 1998. This provides a level of accuracy sufficient
for detailed maps, and that was previously only available using aerial
photography. This technology, originally developed in the U.S. intelligence
community, is incredibly accurate. As one company put it, "It’s like
having a camera capable of looking from London to Paris and knowing where each
object in the picture is to within the width of a car headlight."
Broadband
networks: The data needed
for a digital globe will be maintained by thousands of different organizations,
not in one monolithic database. That means that the servers that are
participating in the Digital Earth will need to be connected by high-speed
networks. Driven by the explosive growth of Internet traffic,
telecommunications carriers are already experimenting with 10 gigabit/second
networks, and terrabit networking technology is one of the technical goals of
the Next Generation Internet initiative. The bad news is that it will take a
while before most of us have this kind of bandwidth to our home, which is why
it will be necessary to have Digital Earth access points in public places like
children’s museums and science museums.
Interoperability: The Internet and the World Wide Web have
succeeded because of the emergence of a few, simple, widely agreed upon
protocols, such as the Internet protocol. The Digital Earth will also need some
level of interoperability, so that geographical information generated by one
kind of application software can be read by another. The GIS industry is
seeking to address many of these issues through the Open GIS Consortium.
Metadata: Metadata is "data about data."
For imagery or other georeferenced information to be helpful, it might be
necessary to know its name, location, author or source, date, data format,
resolution, etc. The Federal Geographic Data
Committee is working with industry and state and local government to
develop voluntary standards for metadata.
Of course, further
technological progress is needed to realize the full potential of the Digital
Earth, especially in areas such as automatic interpretation of imagery, the
fusion of data from multiple sources, and intelligent agents that could find
and link information on the Web about a particular spot on the planet. But
enough of the pieces are in place right now to warrant proceeding with this
exciting initiative.
Potential
Applications
The applications
that will be possible with broad, easy to use access to global geospatial
information will be limited only by our imagination. We can get a sense of the
possibilities by looking at today’s applications of GIS and sensor data, some
of which have been driven by industry, others by leading-edge public sector
users:
Conducting
virtual diplomacy: To
support the Bosnia peace negotiations, the Pentagon developed a virtual-reality
landscape that allowed the negotiators to take a simulated aerial tour of the
proposed borders. At one point in the negotiations, the Serbian President
agreed to a wider corridor between Sarajevo and the Muslim enclave of Gorazde,
after he saw that mountains made a narrow corridor impractical.
Fighting crime: The City of Salinas, California has reduced
youth handgun violence by using GIS to detect crime patterns and gang activity.
By collecting information on the distribution and frequency of criminal
activities, the city has been able to quickly redeploy police resources.
Preserving
biodiversity: Planning
agencies in the Camp Pendelton, California region predict that population will
grow from 1.1 million in 1990 to 1.6 million in 2010. This region contains over
200 plants and animals that are listed by federal or state agencies as
endangered, threatened, or rare. By collecting information on terrain, soil
type, annual rainfall, vegetation, land use, and ownership, scientists modeled
the impact on biodiversity of different regional growth plans.
Predicting
climate change: One of the
significant unknowns in modeling climate change is the global rate of
deforestation . By analyzing satellite imagery, researchers at the University
of New Hampshire, working with colleagues in Brazil, are able to monitor
changes in land cover and thus determine the rate and location of deforestation
in the Amazon. This technique is now being extended to other forested areas in
the world.
Increasing
agricultural productivity:
Farmers are already beginning to use satellite imagery and Global Positioning
Systems for early detection of diseases and pests, and to target the
application of pesticides, fertilizer and water to those parts of their fields
that need it the most. This is known as precision farming, or "farming by
the inch."
The Way Forward
We have an
unparalleled opportunity to turn a flood of raw data into understandable
information about our society and out planet. This data will include not only
high-resolution satellite imagery of the planet, digital maps, and economic,
social, and demographic information. If we are successful, it will have broad
societal and commercial benefits in areas such as education, decision-making
for a sustainable future, land-use planning, agricultural, and crisis
management. The Digital Earth project could allow us to respond to manmade or
natural disasters - or to collaborate on the long-term environmental challenges
we face.
A Digital Earth
could provide a mechanism for users to navigate and search for geospatial
information - and for producers to publish it. The Digital Earth would be
composed of both the "user interface" - a browsable, 3D version of
the planet available at various levels of resolution, a rapidly growing
universe of networked geospatial information, and the mechanisms for
integrating and displaying information from multiple sources.
A comparison with
the World Wide Web is constructive. [In fact, it might build on several key Web
and Internet standards.] Like the Web, the Digital Earth would organically
evolve over time, as technology improves and the information available expands.
Rather than being maintained by a single organization, it would be composed of
both publically available information and commercial products and services from
thousands of different organizations. Just as interoperability was the key for
the Web, the ability to discover and display data contained in different
formats would be essential.
I believe that the
way to spark the development of a Digital Earth is to sponsor a testbed, with
participation from government, industry, and academia. This testbed would focus
on a few applications, such as education and the environment, as well as the
tough technical issues associated with interoperability, and policy issues such
as privacy. As prototypes became available, it would also be possible to
interact with the Digital Earth in multiple places around the country with
access to high-speed networks, and get a more limited level of access over the
Internet.
Clearly, the
Digital Earth will not happen overnight.
In the first stage,
we should focus on integrating the data from multiple sources that we already
have. We should also connect our leading children’s museums and science museums
to high-speed networks such as the Next Generation Internet so that children
can explore our planet. University researchers would be encouraged to partner
with local schools and museums to enrich the Digital Earth project — possibly
by concentrating on local geospatial information.
Next, we should
endeavor to develop a digital map of the world at 1 meter resolution.
In the long run, we
should seek to put the full range of data about our planet and our history at
our fingertips.
In the months ahead, I intend to challenge experts in government, industry, academia, and non-profit organizations to help develop a strategy for realizing this vision. Working together, we can help solve many of the most pressing problems facing our society, inspiring our children to learn more about the world around them, and accelerate the growth of a multi-billion dollar industry.