Macroscopes are instruments to let us make large objects smaller so that we can gain perspective about the objects -- the opposite of microscopes. Microscopes let us blow up a molecule to see what cannot be seen with the human eye and macroscopes let us reduce the world to see what cannot be seen with the human eye.
Macroscopic and microscopic models of reality.
Maps are macroscopes which are used primarily to represent spatial phenomena across the Earth's surface, although maps are not limited to the Earth, to a surface, nor to reality. The smallest object that might be mapped is the land parcel. In general, we would not call a house plan a map but we might use the word map to show the arrangement of findings at an archaeological site or to show the trails in a park. At the other end of the scale we map the surface of an entire planet but we are not likely to use the term map for a diagram of a solar system or the Milky Way. So, maps can be defined by the scale of phenomena being examined.
Scale is a measure of the relationship between the representation of the object and the object itself. If we put the surface of the Earth on a postage stamp, we have a small scale map with a great amount of abstraction and generalization. If we have a map of a park showing trails, restaurants, restrooms, parking and objects of note, we have a large scale map with little abstraction and generalization.
Another attribute of maps is the way we unwrap the curved surface of the Earth and lay it flat. We call this projection. Projection is of great concern in smaller scale maps such as those of the Earth or a continent. However, depending on the purpose of the map, projection may be of less concern for a large scale map such as that of the park.
The third attribute of a map is symbolization--the mix of symbols and text used to portray the background and content. There is great variation in the way maps are symbolized, including the ways data are classified and labeled. Maps may be shown in color or black and white; they may be animated; they may be interactive or they may be virtual and not visible to mere humans. Many things fall under the definition of a map but they all are based on decisions of humans in generalizing, classifying and symbolizing reality. An air photo of a city is not a map although it has scale, projection and uses gray scales or colors to show levels of reflections from the surface. However, when that photo is tied to the surface with coordinates, when boundaries and geographic names are added, this might be appropriately classified as a map. Humans make maps--they are not the raw imagery from a camera, sonar device or satellite sensor.
Thinking of a map as a macroscope with the attributes of scale, projection and symbolization sets the standard to discuss map use.
I contend there are at least six dimensions to an understanding of how and why maps are used. By looking at each of these dimensions we might be able to improve on the ways maps are used. I offer these dimensions of map use. The subheadings are links to additional pages exploring further dimensions of these topics.
These ideas were first developed relative to the activities of the Map Use Commission of the International Cartographic Association. The content of the Commission page summarizes the work we did over our eight-year term of existence.
Below are brief summaries of the six dimensions listed above. In most cases there is a link from the summary to a page where these ideas are developed further. You are invited to react to this material and provide me feedback.
We can assume that any person who uses a map does so voluntarily--that is no one is forcing the person to use a map with the exception of that child in school who examines the map only to satisfy the teacher. If map users are persons who turn to maps by choice, then we know there are other persons who do not choose to use maps either because they do not know about maps, know where to find an appropriate map or find that maps do not give any information worthy of their time. There are many reasons why someone turns to a map while another never thinks of looking at a map, or makes an overt decision to not use a map. Motivation has to be an important factor in explaining why some persons use maps and others do not.
Literacy is a measure of a person's ability to use the written word to read and write. Numeracy is a comparable measure of the ability to use numbers, while graphicacy has been employed to refer to a person's ability to use graphic displays such as charts and maps. Most maps integrate visual displays with text and numbers, so in many cases the map user has to be literate, numerate and graphicate. Obviously, there is great variation in terms of the skills and experience of individuals to use maps. We cannot expect young persons to be effective map users if they are not literate, numerate and graphicate. On the other hand, learning to use maps is one way individuals become literate, numerate and graphicate.
The traditional map employs color and text as symbols are arrayed across space. The persons who can use such maps are likely to have no physical limitations on their ability to view and focus on the visual display. Maps can be quite detailed and complex and therefore can be difficult for some persons to use fully. Many persons have one or more disabilities which may affect their ability to use maps that others can use. In particular persons with vision problems, including color blindness, need special accommodations to use maps. There is a world of tactile maps for those who must see with their fingers.
In summary, there is no simple map user. Users, and non-users, are a diverse lot. These ideas are developed further on the individual map user page.
While we normally think of the map user as the person who views the map and may make decisions based on that act, there are many other ways a person or organization may use a map. Thus, the person who designs and produces a map may be doing it for a specific purpose, perhaps to make an argument or to explore spatial relationships. Likewise, a governmental agency produces maps to fulfill a mission and to modify behavior of a constituency. Similarly, a firm produces and markets maps as a commercial enterprise. It can be argued that all of these persons are map users for they are using maps to accomplish some end.
The ideas of producers, distributors, researchers and presenters being users of maps is developed further on the producers as users page.
In a free society where persons can get access to maps of many subjects in many forms there are unlimited ways in which maps might be used. Indeed, maps appear on pieces of clothing, as shower curtains, on umbrellas, on postage stamps and post cards. In critical situations maps have probably been used as protection against rain, as wall paper, as insulation to fill cracks or as containers to haul water. But, the concern should be how are maps used as maps--as representations of surfaces at the range of scales that define maps.
Many maps are designed and produced to serve very specific uses while other maps contain so much information that they are used by a variety of users for a great variety of activities. For this discussion Map Uses are examined below from the perspective of the generic reasons why a map is designed, produced, disseminated, stored, preserved and/or viewed. On complementary pages are discussions of the way cartographers have classified levels of map use, the tasks involved in using maps, and the functions of using maps.
General Reference - We hear about a fire in Tonto National Forest, our neighbors left for a vacation in Kauai, a volcano erupts on Mindanao. Because we want to know where these places are we need a map. If we do not know where to look, then we should start with an atlas with an index. There are many sources of maps that can be consulted for general reference, including maps posted in public places. With access to the web and a good search engine, we now have another source of maps to find out 'where' places are in our world.
Navigation, Control and Route Planning - Whether we move on land, at sea, or in the air we rely heavily on maps to plan our routes and to maintain our course. We have hiking and biking maps, maps for crawling through caves or orienteering through woods, highway and off road maps, as well as nautical and aeronautical charts. We have maps to show rapids in white water and fishing structure in lakes. We use these maps to plan our routes and then to navigate when we are in motion.
Communication, persuasion and propaganda - Many maps are designed and produced to convey a particular image or communicate a particular idea. Because map data must be classified and represented by symbols, in almost all cases the image cannot be very general. Maps in newspapers accompanying an article or on TV with a report aid in telling the story. Very often those maps are not neutral in terms of the message conveyed. Under this category we might include maps that are used to route traffic in specific directions, maps employed to get people to register to vote, and a number of persons select map projections to convey a specific image; this is particularly true of the Peters projection which advances the argument that it is time for a new image of the world. And, the Australian maps that show the South Pole at the top of the map belong here.
Planning - Because 'where' is important, we use maps to determine where we want to do what. We turn to maps to determine where a communications tower should be located in terms of reception, visual impact, zoning and landuse restrictions. Urban and regional planning rely heavily on maps for the location of schools and public facilities, for the development of highway, sewer and water networks and for the orderly organization of space through zoning and other techniques.. We try to identify areas subject to potential hazards and develop plans for containing problems, evacuating those in danger and providing services. Military operations rely heavily on maps for the deployment of troops, for the assessment of enemy positions, and for targeting weapons.
Jurisdiction, Ownership, Assessment - Maps are used a legal documents showing the ownership of land and boundaries. Cadastral mapping is that area dealing with the legal systems showing who has rights to property. Land that is subdivided is platted and those plats are recorded on maps. Taxes are based on property ownership and assessors rely heavily on maps. In more traditional societies where boundaries have been understood but not documented, efforts are now being made to create maps showing agreed-upon boundaries. These maps are permitting indigenous societies to retain rights to their land against outside forces wanting access to resources.
Understanding Spatial Relationships - Many maps are made in the process of trying to understand how phenomena are distributed spatially. In some cases the subject of investigation may be a single variable and in other cases a number of variables may be examined in relationship to each other and to other non-spatial variables. The classic example of this is the work of Dr. John Snow creating the map of the incidence of cholera in London and finding that the patterns led to a public water pump. (Monmonier, 1991, 142) The development of the concept of Plate Tectonics was based on a great amount of mapping and map analysis around the world. Police and public officials map data to see if there are patterns in the behavior of crime.
Forecasting and Warning - The weathercaster on television is but one component of the use of maps to predict the future of events that play out over the Earth's surface and that have the potential for significant damage to systems important to humans. Such forecasting and the dissemination of warnings is done at many scales, ranging from quite localized flash flooding, wildfires, and tornado touchdowns to larger features like hurricane landfalls, severe storms, volcanic eruptions, insect infestations, tsunamis, and sea level rise and high tides. Maps are an important part of the prediction processes and are equally important in forewarning potential victims.
Map Compilation - The making of a map in almost all cases requires the use of maps. Map production is an iterative process and in that process a number of maps may be made as we converge on a appropriate design. In many cases we consult other maps for such things as checking geographic names, confirming boundary changes, or examining land use and topography to better place dots on a map portraying the distribution of dairy cattle in a region.
Decoration, Collection and
Investment - Maps are collected, sold and displayed simply because
they are maps and many people like the appearance of a map. Historic
maps take on value based on their rarity, quality and area of
interest. It is common to see historic map images employed as
decoration on clothing, walls, games and puzzles. And, there is the
occasional use of map images in advertisements, perhaps as a background.
In our digital world of Geographic Information Systems
many local and regional governments maintain databases for the storage of
information and they do not want to employ tangible maps for the storage
of information, because such maps are static. In this environment
maps are generated as they are needed because the database is updated
constantly. Any tangible map may be outdated and when dealing with
questions of infrastructure this might by critical.
Summary - In many cases the same map may be used in
many different ways. Most of us have used a highway map for general
reference, for route planning, for navigation, and for
communication. Those of us who have compiled maps have probably used
one or more of these maps in compiling another map. And, people
collect and invest in older highway maps. This illustrates that map
use can be somewhat independent from the map. While another map
might be more appropriate to a task, if the highway map is available and
you don't know about the other map, you turn to the highway map because it
is available. On complementary
pages are discussions of the way cartographers have classified levels of map
use, the functions of
using maps, and the tasks involved in
The Map Use Environment
A century ago almost all maps were printed on paper. Some of those maps would have been in color and there would have been great variation in format, ranging from large single sheets, to atlases, to a single map on a printed page. With advances in technologies we now find maps in many other formats. Perhaps the greatest viewing audience of maps is found on television where weather maps are shown at regular intervals on a number of different stations. Weathercasters cycle through a variety of weather maps to portray what has happened and what is predicted to happen. These maps are in color and some employ simulated perspectives to give them a 3-D look. Many of the presentations are animated showing change over time and in some cases the maps show change in real time. Traditionally, the maps are shown one time and then the television programming moves on to another topic. Viewers get to see the map once and there is no going back to check on what you thought you saw. And, that the television screen is of quite coarse resolution so that maps have to be fairly simplified. On the other hand, because the viewer is not supposed to sit close to the television screen the image is designed to be read from across the room.
By contrast, the same weather maps could have been produced using ink on paper. The printing arts can produce a map with fine details and therefore far more information can be included on the single map. A greater variety of colors can be distinguished on the paper map. The viewer of the printed map can lay the map out on a table and pour over the map, studying it in detail. The viewer can make measurements on the map and can annotate the display. In this environment the user is in control of the viewing of the map. However, this hardcopy product cannot be very current and cannot show real time events. On the printed map, change has to be shown by a sequence of maps side by side.
These two examples show two extremes in the environments in which maps are can be viewed. Automobiles, ships and planes are equipped with map displays where the individual has immediate map information to help navigate while being attentive to other tasks at the same time. Golf carts are now equipped with map displays to show the placement of the pin on the green and details on the course to get to the green. Maps are being created for the mobile cell phone so that users can see spatial information where they need it when they need it.
Users of the Web can find many maps for immediate display, as well as maps that can be downloaded and displayed on the personal workstation. There are other sites where users can access a database and create a map by selecting class intervals and color symbols. In these cases the user gets to interact with the data to create one or more maps. Beyond this are those who are exploring visualization in cartography where a user has even more flexibility in exploring spatial data and being involved with the creation and exploration of maps.
The world of map use environments is pushed even further in applications in the military, based on many news reports and stories. Integrating maps with global positioning systems such as GPS has done much to let the user be more involved with the map data. And, in some of these more advanced environments, the maps and map-based decisions are based on intelligent systems in which the human is not central to the process.
Thus, the way a person can use a map depends on the environment in which the map can be viewed and used. It should be noted that the condition of the physical environment should also be considered for maps are viewed in bright sunlight, dim light, rolling seas, heavy traffic, turbulent weather, rain, high winds and under fire. These ideas are developed further on the map use environment web page.
The Map or Maps Being Used
The ability to use a map is dependent on the nature of the map. First, the map must be readable, the symbols distinguishable and the user can see the image, or images. Assuming the map meets these criteria then there are other factors that will determine how useful the map will be. Maps are international and therefore we might see a great variety of languages on maps. If we work in English, then we depend on geographic names to be translated, or transliterated, from the native language into English. Thus, on older maps of China we see Peking but on newer maps we see Beijing.
My interest in map use evolved from my experience of working with an article and accompanying map of the USA showing the concentration of an atmospheric variable. As I dug into the nature of the map I found the patterns on the map were quite misleading. It took considerable effort to find the flaws in the map and I published a critique of the map. (Carter, 1972) I was then surprised to find that the article with the map was republished in a edited work. I have employed this article and another which incorporated a good map into my teaching for three decades and have learned by student reactions what they see and do not see on the maps. (Carter, 1979)
Later a colleague approached me because a map he was to present as a slide had been rejected because it was not readable as a slide. Following the strict guidelines of the referees, I redesigned the map to meet their standards. It took two iterations before I got it right, but when it was done I realized the effect of appropriate design on the way the map can be used. It changed my ways of thinking about map design and use. (Carter, 1988)
Gersmehl (1985) reflected on how one of his maps had been misused and considered what he could have done to minimize the possibility of abuse. He had published a series of maps of the USA using dots to represent the distribution of soil types. In some of the western states, Histosol soils are present in widely scattered patches. Using conventional techniques, Gersmehl used a single dot to show that there was a small amount of Histosols in each of those states. He found that subsequent map makers interpreted those single dots to be the location of large deposits of that soil type. This tale should be required reading for anyone looking at the effects of map design on the use of the map.
Data classification is common in maps, whether it be in the selection of the contour interval, the representation of vegetation cover, road types or hazards to navigation. The image of the map will be determined in part by the way the data are classified. This is well illustrated by working through the online thematic mapping program of the American FactFinder web site of the U.S. Census Bureau. Upon entering the site, a choropleth map of the population density of the states of the U.S. is shown, with data broken into 5 classes based on natural breaks. Clicking on the blue Legend button on the left, users can change the classification and symbolization of the map. For example, selecting six classes, the orange color sequence and quantiles produces a distinctly different map, although the extreme areas that were high and low on the first map will be high and low on the new map. This exercise should demonstrate that the map will have some impact on the ability of a user to make effective use of a map. Thankfully, most maps will not be so affected by data classification as shown by this illustration.
The effects of data classification were evident in a recent meeting when a group of us met to evaluate where to focus attention on sub-watersheds in a local drainage basin. The discussion was based on comparing many maps in a report generated from a GIS. Persons who knew the area were surprised that some sub-watersheds had been grouped into the same category as other watersheds. Subsequently we realized that the maps reflected the choice of data classification and not reality. In this case, the map was not a good representation of the nature of the data and therefore was misleading the users of the map.
Indeed, the nature of the map does have an impact on how maps can be used and/or on how they will be used. It takes an insightful map user to understand what the map shows, what that image represents and what can be read from that image.
Map User Communities
In many cases the maps that are available for users are the product of a community which has set the standards for the nature of the maps. It is a complex world and there are great varieties of maps, but the core of the maps are based on the work of producers, professional societies and government agencies to see that maps are produced according to standards. And, the standards have evolved over time, in part due to the feedback from users.
When we look at weather maps we expect to find a surface chart with isobars and fronts. The warm, cold and stationary fronts are always symbolized the same way. Why do these maps have this same appearance? It is because over the years the weather community set some standards and producers and users live by those standards. Now we have live radar maps showing the track of a precipitation event over the past few hours. The color sequences employed to symbolize the radar echoes are fairly standard so that users can easily distinguish the implications of green and red patches. These standards are not locked in law, but exist because of the cooperation of the communities of persons producing maps for a variety of users.
One aspect of standards and map usability is the scale of the map. In the United States the base of the printed topographic map series is at a scale of 1:24,000 while it is at 1:25,000 in many other countries. All of the topographic maps of the world have a common look to them. Users can turn to these maps and be comfortable knowing what degrees of generalization exist on the maps and therefore what can be gained from the use of a map at this scale and what cannot be seen at this scale. The U.S.A. also publishes topographic maps at scales of 1:100,000 and 1:250,000. At each of these scales there is greater generalization and it is incumbent on the producers of these maps to make certain the maps are up to the standards appropriate to that scale. And, it is equally incumbent on the map user to know what can and cannot be read at each of these scales. For an overview of topographic maps in the U.S. see my class page.
The communities in support of nautical and aeronautical charting have an even greater need to set standards and produce maps at those standards, for nautical charts are aides to navigation and as such many people live and die by the quality of the chart and the ability of persons to use those charts. In the age of printed maps, currency is maintained by publishing fixes are regular intervals and users have a responsibility to be aware of all possible fixes. In the digital age, the most current map can be served as needed, ideally.
The look of the map, and thus the things shown on the map, will be dictated in part by what the user expects to see on the map. When the user looks at a printed highway travel map he/she will see a rather conventional set of symbols, no matter where they are in the world. The text language of the map will vary by country, and the selection of colors will vary by producer, but the overall image will be fairly similar. There is no authority to set standards for such maps but the unwritten alliance between the user and the producer has led to conventions that make the maps usable.
In the 1990's the bicycling community of the Netherlands conducted experiments to try to improve on the usability of their maps. They developed some prototype maps and tested them among cyclists. Based on the feedback from users, they refined the image of bicycle maps in their country. (Elzakker, 2001) Here is an example of a community of users taking it upon themselves to develop new standards for their maps. Observing and measuring the usability of an item has become popular in industry in recent years. Certainly, somewhere these measures of usability have been applied to the appearance and use environments of maps.
Matching the potential map user with appropriate maps involves another community, or other communities. Human society is built on the past and we maintain libraries where we can store and recover that past. Maps are a significant part of the library collections of the world and because of the unique nature of maps we have persons who focus on map librarianship. One of the tasks of these person is to protect and preserve that historical record in such a manner that it is available to those who have cause to use the maps. Equally important is the role of these persons in working with users to match users with the map or maps that meet their demands. Perhaps the map does not exist, but it takes an authority to know what does and does not exist relative to any search. There is a definite community of map librarians and they stay connected through a computer listserv. I have been a part of this listserv for more than a decade and it is interesting to see how map librarians try to match users to maps. In this same mode, mention should be made of the map dealers, those persons who scour the world for maps so that they can put maps into the hands of map users.
As we move into the more digital environments, the roles of the map user communities have been changing. Now the task may be to help the user find the appropriate files and combine those files into a useful map on a computer. Or the task may be to write good metafiles so that the user can determine the quality and scale of the data to minimize misuse of any maps that are created. Thankfully, there are those map user communities which are concerned about serving users as they produce maps and spatial data.
Societal Impacts From The Use And Abuse Of Maps
In the situations discussed above, the focus is on the persons who touch, view or feel the maps and are directly related to the maps. There are larger communities that benefit from the use or misuse of maps but are likely to be unaware that maps exist or are involved in something that might have effected them. In Gersmehl's article (1985) about the misuse of his Histosol map, he goes further to suggest that subsequent maps based on his map might have been misused to qualify some states and eliminate other states from competition for a large federal grant. Thus, many people might have been effected by decisions based on the use or misuse of these maps.
Infrastructure is thought of as those capital investments that help us become more productive and good maps and quality spatial data are part of the infrastructure of a nation, region or community. This thinking has led to the creation of the term National Spatial Data Infrastructure, or NSDI, to refer to systematic organizations of maps and mapping in the United States. Other nations have similar concerns and there is a Global Spatial Data Infrastructure organization. With a good SDI we should expect to see intelligent decisions made about planning and resource use, appropriate warnings targeted at those who need be concerned in the event of emergencies, and proper routing of traffic and material. Society will benefit or suffer depending on the nature of our spatial data infrastructure and how we use that infrastructure.
In 1992, the people in Chicago learned about infrastructure when the wall of a tunnel underlying the city was penetrated by a firm building a retaining wall. The waters of the Chicago River and Lake Michigan poured into the tunnels which had been built decades before to serve the overlying buildings. The area remained flooded for weeks at great cost to society. Few people knew of the tunnels and therefore no concern had been shown for avoiding this potential problem. Such events have driven the push to put together a well integrated spatial data infrastructure that minimizes the likelihood of events of this nature.
Just as society is concerned that we can get the proper information to the right persons at the right time, society is also concerned that the wrong people cannot get certain information at certain times. Maps and spatial data have security implications and there will always be a concern as to who can have access to maps. In many countries the topographic maps of the country are readily available to the citizens but in some countries access to such maps may be highly restricted. Maps are information and if the controllers of the information do not want that information to be made public, then the maps may not be made available.
There are many other aspects of the societal use of maps. At the World's Fair in Knoxville, Tennessee, in 1982 Saudi Arabia had a pavilion. Their brochure included an outline map showing the location of their country and neighboring countries but the name and boundaries of Israel were not shown on the map although the area occupied by Israel was shown on the map. Later it was observed that what we think of as the Persian Gulf was labeled the Arabian Gulf. A spokesperson for the pavilion stated "It depends on whose atlas you look at." (Warnick, 1982) Boundaries and geographic names are points of contention and are reflected on maps.
In the mid-1990's the U.S. was launching missiles in Yugoslavia when a missile hit the Chinese Embassy and killed three officials. The missile appears to have followed the course it was to travel, but the map used to target the missile was out of date. Since the map had been made the targeted activity had moved out of that building and the Chinese Embassy had moved in. So, three people died and an international incident arose because someone made a error in the use of a map. Many societies were affected by this activity.
When a hurricane approaches a coast the weather forecasters and emergency management people have to make the decision of if and where the storm is likely to come ashore, the strength of the storm on landfall, the progress of the storm over land, the potential damage from the storm, and who needs to evacuate and to where people should evacuate. To make these decisions requires a great amount of map analysis on the part of the persons making the forecasts and directing residents to prepare, evacuate or do nothing. Then the television and radio personalities have the responsibility to communicate to the public in a way that the residents know what they should do. Of course maps will be used, whether displayed on television or described over the radio. In cases of this nature a great burden is placed on society to get it right. It is very costly to fail to have evacuated people when they should have moved, but it is also costly to have people take action and move when it was not necessary. A major concern is the credibility of the persons who make these forecasts and issue the commands, and the quality of their work is based heavily on maps and spatial data. Society relies on the map communities to have good spatial data and use it properly.
These examples show that many societies are affected by the use or misuse of maps and that in most cases the public is never aware of being a party to the events.
This statement argues there are six aspects or dimensions to the use of maps. This makes it sound like using maps is very complex, and in some ways it is very complex. On the other hand, people have been using maps for centuries so it cannot be all that complex.
The potential complexity was captured when Ormeling (1997, 21) wrote: ". . . we must be concerned that not only do we get the right data to the user but that the user gets the data right." When this quote is considered in light of the many dimensions of map use, it is a complex world.
Carter, James R., 1972, "Commentary on Mason's 'Spatial Variability of Radioactivity in the United States," The Professional Geographer, Vol. 24, (Feb. 1972), 77-80.
Carter, James R., 1979, "Two Maps--Many Images," Proceedings of the American Congress on Surveying and Mapping, 39th Annual Meeting, 1979, 153-159.
Carter, James R., 1988, "The Map Reading Environment: A Significant Factor in Cartographic Design," The American Cartographer, Vol. 15, No. 4, Oct. 1988, 379-85.
Elzakker, C.P.J.M. van; A.W. Simon van Leeuwen & E. Massop, 2001, Investigations into the use of Dutch cycling maps and their results. The Cartographic Journal, 38(1), pp. 41-47. ISSN 0008-7041.
Gersmehl, Phillip, 1985, "The Data, the User and the Innocent Bystander: A Parable for Map Users, The Professional Geographer, 37(3), pp. 329-334.
Monmonier, Mark, 1991, How to Lie With Maps. Chicago: The University of Chicago Press.
Ormeling, Ferjan, 1997, “Map Use Steps and Their Data Quality Requirements” Cartographic Perspectives, 28, pp. 21-24.
Warnick, Marta, 1982, "Saudi's Map Causes Another Stir sa Visitors Discover a Big Gulf in Political Geography," Knoxville News-Sentinel, July 9, 1982.
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