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19 Cards in this Set
- Front
- Back
Toblers First Law of Geography
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Everything is related to everything else, but near things are more related than distant things
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Representations -
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Help us assemble far more knowledge about the earth
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Digital representation
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low cost, and simplicity allows for many uses
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Geographic representation
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deals with the earths surface or near surface.
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Binary System
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all of the earths data is ultimately reduced to binary
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Age of Discovery
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Maps became vital pieces of information
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Key GIS representation issues
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What to represent and how to represent it.
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Geographic data links?
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place, time, and attributes.
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Classification of geographic attributes
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nominal, ordinal, interval, ratio, cyclic.
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Two fundamental ways of representing geography
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discrete objects and continuous fields
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Continuous field view
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represents the real world as a finite number of variables, each one defined at every possible position.
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discrete object view
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represents the geographic world as objects with well-defined boundaries in otherwise empty spaces
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What are the methods of representing data in a computer?
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Raster and vector methods
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Raster representations
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divide the world into arras of cells and assign attributes to the cells
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Paper Map
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a source of data for geographic databases, an analog product from a GIS, and an effective communication tool
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digital line graph
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every geographic feature is shown on the map is represented as a point, polyline, or polygon. Symbols are replaced with associated attributes
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digital raster graph
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map is scanned at a very high density using small pixels so the raster looks like the original.
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generalization rules
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simplification, smoothing, aggregations, amalgamation, merging, collapse, refinement, exaggeration, enhancement, displacement.
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weeding
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is the process of simplifying a line or area by reducing the number ofpoints in its representation
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