Introduction to Earth Systems: Lesson 1 Earth Systems   Reading Assignment: Internet link:  Themes in the study of earth systems NAVIGATION (To return, use back button) Reading Key Concepts Discussion More Links Exercises
Side Notes	Key Concepts	Links
Examples of earth systems                 Systems of human activity	These are the key concepts in this lesson. You should be able to define or describe them after you have read this lesson, finished the assigned reading and explored the links. You should also be able to do the exercises and answer the questions at the end of the lesson. earth system natural system spatial data map report generating Systems An earth system is a collection of interrelated entities, circumstances and patterns that is significant for its relationship with the physical condition of the planet, including its life forms. In specific instances, such a relationship, while substantial, might be also be significant for its effect on other systems, e.g. the effect of land management on rain-induced soil erosion, the effect of topography on the design of highway systems. The union of all such systems, identified or not, comprises "the earth system." For examples of earth systems, A local weather pattern Global weather A transcontinental transportation system A system of land management practices Regional topography Seasonal animal migration Stratospheric air currents Exploration for and production of petroleum Certainly there are collections of interrelated entities, circumstances and patterns that seem to have no apparent significant effect on the physical condition of the planet. Some candidates for examples of such systems are A national monetary system The world monetary system as a collection of national monetary systems and their relationships The structure and organizational facts that comprise a specific symphony orchestra The United States Postal Service The laws and practices in England governing property ownership within marriages The American Mathematical Society A collection of specifications and activities that comprise an Internet-based course in creative writing The effect of certain organized religions on the attire of their constituents .	The Earth System
Interaction between nature and human activity	As suggested by the list of examples above, systems that appear not to have direct effect on the condition of the planet as we see it are likely to be systems of human activity. Other systems are part of what is often called "nature." We observe such systems among plant life, animal life, geology, the oceans, weather, etc. Much of our motivation for this study is from the interrelationships among systems of human activity with those from "nature." For examples, The effects of weather on transportation systems Acid rain: Airborne pollutants from one part of Earth's surface are carried by rain systems to another surface location Impact of the U.S. Postal Service on natural resources and habitats: The activities of the U.S. Postal Service stimulate paper manufacture, thereby affecting the harvest of forest timber and, under current practices, generating substantial chemical effluent into rivers. The U.S.P.S. operates thousands of vehicles that consume fossil fuels The effects of drought on farming activity The effect on climate of release into the air of large volumes of manufactured gasses, e.g. chloroflourocarbons and exhaust gasses from fossil fuels The effects of earthquakes on man-made systems, e.g. road systems, business operations, residential communities Of course, interaction among earth systems pre-dates the effects of human activity, e.g. The effects of volcanic activity on surrounding plant and animal life Plant damage caused by insects Food chains The effects of floods, drought, fire, rain, flood, erosion on land forms And systems of human activity tend to interact with other such systems, e.g. The effects of lobbying by fuel manufacturers on legislation related to air pollution Demands on public transportation systems imposed by sporting events Changes in stock market trading practices caused by availability of internet communication Interrelation between human thought and speech Regarding condition of the planet as inextricably entangled with its resident life forms, and acknowledging the large and increasing effect of human occupation on other life forms and on the condition of the planet, we will find that our study of earth systems includes study of some systems of human activity.	Themes in the study of earth systems                 Related activities and more examples
Data related to location	Spatial data Descriptions of earth-based phenomena, when not global, generally specify location as part of their identification. In many contexts, we regard the surface of Earth as spherical. Location on the surface of the sphere is achieved, in any of several coordinate systems, with two coordinates. In the most common of the systems, the components are latitude and longitude. Careful determination of location eventually includes attempts to account for deviations of the planet from spherical shape. In some contexts, it is useful to supply a third component; elevation represents vertical distance from mean sea level. We refer to data that is associated with location as "spatial data" or "spatially-based" data. And we will see that data which does not include an explicit spatial component is usually, by default or prior specification, assigned some spatial identification anyway, e.g. applied to the entire county, state, country, continent or planet.	Examples of spatial data.
Maps as visual documents	Maps Visual perception   Visual perception of location is a basic survival tool among many forms of animal life and it predates human language. Sight is nearly indispensable for many predators, and prey. In many settings, simply going home involves use of sight with other senses. And while spoken language can enhance description of location, visual representation of location, as contrasted with visual perception, facilitates planning, memory and communication. While spoken and written language tend to be sequential, and so one-dimensional, maps of geographical location are usually two-dimensional or three-dimensional. But there are useful one-dimensional representations. For examples A timeline describing a single geographical location: An event requires only one component, i.e. the number-name of a year, for its place on the timeline Route maps along a highway: Places along the highway are identified in terms of one component, i.e. distance from a starting place A schematic diagram of a route, not preserving distance or shape, but preserving ordinality, i.e. showing locations in their order along the route Most maps are two-dimensional, i.e. identifying location requires two components. And, for many practical reasons, the history of centuries of map-making is also the history of an attempt to represent non-planar (not flat) surfaces on planar (flat) media. Since the sixteenth century, with growing acceptance of the shape of Earth as essentially spherical, there have been many attempts at constructing representations in a plane of Earth's nearly spherical surface. Such projections of Earth to a plane represent many collections of advantages and compromises. Accurate representation of shape, magnitude and continuity of the entire planet on a flat surface is impossible.	Examples of maps and data
Geographical information systems	Report-generating Geographical maps are necessarily incomplete. They are not large enough to represent all visible detail, political subdivisions, etc. Hence the use of themes among available data in presenting spatial data, e.g. illustrating an earth system. For examples, most road maps are too small, or represent areas too large, to allow accurate representation of buildings; infra-structure maps, e.g. of power lines or pipelines, generally do not include details about other facilities. From an extensive spatial data base, simultaneous display of all of the data is rarely, if ever, done. Most applications constitute visual reports selecting themes, e.g. trees, infra-structure, buildings, to allow for clarity and ease of viewing. A combination of such reporting capability with computer-based spatial data comprises a geographical information system (GIS). Links Commercial site. Free mapping service. Map collection Univ. of Calif. map library, aerial photos Harvard map collection Cartography links GIS Data source       TOP   Discussion Exercises Describe two examples of earth systems that existed twenty thousand years ago.   Describe two earth systems that are primarily a result of human activity.   Describe two examples of spatial data, i.e. data that would be associated with location.   Which of the following are usually taken as spatial data? Location of various cities in the United States Wave lengths of the colors in the visible spectrum Dates of Easter during the twentieth century Percentage, by precinct, of voters participating in a general election Air pollution index at a given time The number of calories in a hamburger   Which of the following seem/are natural systems, i.e. systems that apparently exist without human influence? Continental drift A national election in the United States Migration of whales Earth's global weather system Ocean tidal motion Seasonal changes in farmland soil chemistry Production of chicken eggs