阿尔·戈尔 数字地球：认识二十一世纪我们所居住的星球 (有中文翻译)

The Digital Earth: Understanding Our Planet in 21st Century
数字地球：认识二十一世纪我们所居住的星球

Al GORE
阿尔·戈尔

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 kin

ds 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 ha

nd, 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, NASA's 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, in 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, especi

ally 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 a

nd 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 d

ollar industry.


一场新的技术革新浪潮正允许我们能够获取、储存、处理并显示有关地球的空前浩瀚的数据以及广泛而又多样的环境和文化数据信息。大部分的这类数据是“参照于地理坐标的”，即数据的地理位置是参照于地球表面的特定位置。
充分利用这些浩瀚的数据的困难之处在于把这些数据变得有意义——即把原始数据变成可理解的信息。今天，我们经常发现我们拥有很多数据，却不知如何处置。有一个很好的例子可以说明这一点。陆地卫星（LANDSAT）是设计来帮助我们了解全球环境的，它在两星期内将全球拍摄一遍，并已经这样持续收集图像数据二十多年了。尽管存在着对这些数据的大量需求，但是这些图像的绝大部分并未使任何一个人的任何一个神经细胞兴奋起来——它们仍静静地躺在电子数据仓库里。正如我们过去一个时期的农业政策一样，一方面生产的粮食被堆积在中西部的粮食仓库里霉烂，另一方面却有数百万人被饿死。现在，我们贪婪地渴求知识，而大量的资料却闲置一边，无人问津。
把信息显示出来能部分地解决这个问题。有人曾经指出，如果用计算机术语来描述人脑，人脑似乎有较低的比特率和很高的分辩率。比如，研究人员很早就知道，在短时记忆中，人们很难记住七个以上的事项，这就是比特率低下。另一方面，如果把大量的数据相互关联地排列成可辩认的图案——如人脸或是星系，我们却能在瞬间理解数十亿比特的信息。
目前人们通用的数据操作的工具--如象在Macintosh和Microsoft操作系统上所用的被称为“台式隐喻（desktop metaphor）”的图形工具等--都不能真正适应这一新的挑战。我相信我们需要一个“数字地球”，一种关于地球的可以嵌入海量地理数据的、多分辨率和三维的表示。
比如，可以设想一个小孩来到地方博物馆的一个数字地球陈列室，当她戴上头盔显示器，她将看到就象是出现在空中的地球。使用“数据手套”，她开始放大景物，伴随越来越高的分辨率，她会看到大洲，随之是区域、国家、城市、最后是房屋、树木以及其它各种自然和人造物体。在发现自己特别感兴趣的某地块时，她可乘上“魔毯”，即通过地面三维图像显示去深入查看。当然，地块信息只是她可以了解的多种信息中的一种。使用数字地球系统的声音识别装置，小孩还可以询问有关土地覆盖、植物和动物种类的分布、实时的气候、道路、行政区线，以及人口等方面的文本信息。在这里，她还可以看到自己以及世界各地的学生们为“全球项目”收集的环境信息。这些信息可以无缝地融入数字地图或地面数据里。用数

据手套继续向超连结部分敲击，她还可以获得更多的有关她所见物体的信息。比如，为了准备全家去国家黄石公园渡假，她策划一个完美的步行旅游，去观看刚从书中读到的喷泉、北美野牛和巨角岩羊。甚至在离开她家乡的地方博物馆之前，她就可以把要去步行旅游的地方从头到尾地浏览一遍。
她不仅可以跨越不同的空间，也可以在时间线上奔驰。为了去参观卢浮尔宫，她先在巴黎作了一番虚拟旅游之后，又通过细读重叠在数字地球表面上的数字化地图、时事摘要、传说、报纸以及其它第一手材料，她便回到过去，了解法国历史。她会把其中一些信息转送到自己的Email库里，等着以后研读。这条时间线可伸回很远，从数日、数年、数世纪甚至到地质纪元，去了解恐龙的情况。
显然，这不是一个政府机构，一个产业或一个研究单位能担负起的事业。就象万维网（WWW）一样，它需要有成千上万的个人、公司、大学研究人员以及政府机构参加的群众性努力。虽然数字地球的部分数据将是公益性的，但是也有可能成为数字化市场，一些公司可将大批的商业图像从中出售，并开展附加值信息服务。它也可能形成一个“合作实验室”——一个没有墙的实验室，让科学家们去弄清人与环境间的错综复杂的奥妙。
数字地球所需要的技术
虽然这一方案听起来活象科幻小说一样，然而建设数字地球的大部分技术和能力或是已经具备或是正在研制。当然，数字地球本身的能力也将随着时间的推进而不断增强，2005年时的数字地球与2020年的相比较，前者就会显得初级多了。下面是几项所需要的技术：
计算科学：在发明计算机之前，以实验和理论研究的方法来创新知识都很受局限。许多实验科学家想研究的现象却很难观察到——它们不是太小就是太大，不是太快就是太慢，有的一秒钟之内就发生了十亿次，而有的十亿多年才发生一次。另一方面，纯理论又不能预报复杂的自然现象所产生的结果，如雷雨或是飞机上空的气流。有了高速的计算机这个新的工具，我们就可以模拟从前不可能观察到的现象，同时能更准确地理解观察到的数据。这样，计算科学使我们能超越了实验与理论科学各自的局限。建模与模拟给了我们一个深入理解正在收集的有关地球的各种数据的新天地。
海量储存：数字地球要求储存数倍个1015字节的数据。今年年末，美国宇航局（NASA）实施的地球行星项目每天都将得到1012字节量级的数据。所幸的是，在这方面我们正进行着奇迹般的改进。
卫星图像：美国政府部门已经批准从1998年年初开始提供分辨率为1米的卫星图像的商业卫星

系统。这达到了制作精确详图的水准，而在过去这只能由飞机摄影才能办到。这种首先在美国情报界研制出来的卫星图像技术非常精确。正象一家公司所比喻的，“它象一台能从伦敦拍巴黎的照像机，照片中象汽车前灯间距离大小的每种物体”都能看清。
宽带网络：整个数字化地球所需的数据将被保存在千万个不同的机构里，而不是放在一个单独的数据库里。这就意味着参与数字地球的各种服务器需由高速的种种计算机网络联接起来。在因特网通信量爆炸性增加的驱使下，电信营运部门已经试用了每秒可以传送一万兆比特的数据的网络。下一代因特网的技术目标之一就是每秒传送一百万兆比特的数据。要使具有如此能力的宽带网络把大多数家庭都接通，这还需要时间，这就是为什么有必要把连通数字地球的站点放在象儿童博物馆和科学博物馆这样的公共场所。
互操作：因特网和万维网能有今天的成功，离不开当时出现的几项简明并受到广泛赞同的协议，如因特网协议（Internet Protocols）。数字地球同样需要某种水准的互操作，以至由一种应用软件制作出的地理信息能够被其它软件通用，地理信息系统产业界正在通过“开放地理信息系统集团（Open GIS Consortium）”来寻求解决这方面问题的答案。
元数据：元数据是指“有关数据的数据”。为了便于卫星图像或是地理信息发挥作用，有必要知道有关的名称、位置、作者或来源、时间、数据格式、分辨率等等。联邦地理数据委员会（FGDC）正同工业界、以及地方政府合作，为元数据制定自发的标准。
当然，要充分实现数字地球的潜在力还有待技术的进一步改进，特别是这些领域：卫星图像的自动解译，多源数据的融合和智能代理，这种智能代理能在网上找出地球上的特定点并能将有关它的信息联接起来的。所幸的是，现在已有的条件足够保证我们去实施这一令人激动的创想。
潜在的应用
广泛而又方便地获得全球地理信息使得数字地球可能的应用广阔无比，并远远超出我们的想象力。如果我们看看现今主要是由工业界和其它一些公共领导机构驱动的地理信息系统和传感器数据的应用，就可以从中对数字地球应用的种种可能性有一个概貌。
指导仿真外交：为了支持波斯尼亚地区的和平谈判，美国国防部开发出了一个对于有争议边界地区的仿真景观，它能让谈判双方对此地区上空作模拟飞行。一次，塞尔维亚主席在查看到萨拉热窝与哥端得地区的穆斯林领地之间的通道由于山峦阻挡变得狭窄时，便同意放宽该通道。
打击犯罪：加利佛尼亚州的萨里拉斯城市，运用地理信息系统来监视

犯罪方式和集团犯罪活动情况，从而减少了青年手枪暴行。根据收集到的犯罪活动的分布和频率，该城还可以迅速对警察进行重新布署。
保护生态多样性：加利佛尼亚地区的庞得隆野营地计划局预计，该地区的人口将从1990年的一百一十万增到2010年的一百六十万。该区有200多种动植物被联邦或州署列为受到危险、威胁或是濒于灭绝的动植物。科学家们依据收集到的有关土地、土壤类型、年降雨量、植被、土地利用以及物主等方面的信息，模拟出不同的地区发展计划对生态多样性的影响。
预报气候变化：在模拟气候变化上的一个重要未知量是全球的森林退化率。美国新罕布什尔州大学的研究人员与巴西的同事们合作，通过对卫星图像的分析，监测亚马孙地区土地覆盖的变化，从而得出该地区的森林退化率以及相应位置。这一技术现在正向世界上其它森林地区推广。
提高农业生产率：农民们已经开始采用卫星图像和全球定位系统对病虫害进行较早的监测，以便确定出田地里那些更需要农药、肥料和水的部分。这被人们称为准确耕种或“精细农业”。
今后的路
我们有一个空前的机遇，来把有关我们社会和地球的大量原始数据转变为可理解的信息。这些数据除了高分辨率的卫星图像、数字化地图，也包括经济、社会和人口方面的信息。如果我们做得成功，将带来广阔的社会和商业效益，特别是在教育、可持续发展的决策支持、土地利用规划、农业以及危机管理等方面。数字地球计划将给予我们机会去对付人为的或是自然界的种种灾害，——或者说能帮助我们在人类面临的长期的环境挑战面前通力合作。
数字地球提供一种机制，引导用户寻找地理信息，也可供生产者出版它。它的整个结构包括以下几个方面，一个供浏览的用户界面，一个不同分辨率的三维地球；一个可以迅速充实的联网的地理数据库以及多种可以融合并显示多源数据的机制。
把数字地球同万维网作一下比较是有建设性意义的(事实上它可能依据万维网和因特网的几个关键标准来建立)。数字地球也会象万维网一样，随着技术的进步以及可提供的信息的增加而不断改进。它不是由一个单独的机构来掌握，而是由公共信息查询、商业产品和成千上万不同机构提供的服务组成。就象万维网的关键是互操作一样，对于数字地球，至关重要的能力是找出并显示不同格式下的各种数据。
我相信，要使数字地球轰轰烈烈地发展起来的最初方式在于建立一个由政府、工业界和研究单位都参与的实验站。该站的目标应集中在以下较少的若干方面的应用上：教育、环境、互操作以及

如私有化等方面的有关政策问题。当相应的原型完成后，这就可能通过高速网络在全国多个地方试用，并在因特网上以有限程度方式对公众开放。
十分清楚的是，数字地球不会在一夜之间发生。
第一阶段，我们应集中精力把我们已有的不同渠道的数据融合起来，也应该把儿童博物馆和科学博物馆接上如同前面说的“下一代因特网”一样的高速网络，让孩子们能在这里探索我们的星球。应该鼓励大学同地方学校及博物馆合作来加强数字地球项目的研究——目前可能应集中在当地的地理信息上。
下一步，我们应该致力于研制一米分辨率的数字化世界地图。
从长远看，我们应当努力寻求使有关我们星球和我们历史的各个领域的数据垂手可得。
在以后的数月里，我将提议政府机构、工业界、研究单位以及非盈利机构里的专家们行动起来，为实现这一美好前景制订战略方案，大家一起努力，我们就能解决大部分我们社会面临的最紧要的问题，激励我们的孩子更多地了解他们周围的世界，并且加速数十亿美元的工业的增长。