Term
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Definition
| the subjective response to the physical stimulu of the actual density of the objects in a visual field |
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Term
| Center of Gravity Principle |
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Definition
| Placement of the dot in its territorial domain in the way that best represents all the individual elements in the domain. |
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Term
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Definition
| merging of the dots in dense areas; the visual integrity of individual dots is lost |
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Term
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Definition
| method of producing a map whose purpose is to communicate the spatial variability of density of discrete geographic data; also simply called dot mapping |
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Term
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Definition
| the area represented by each dot on a dot map, also referred to as the dot's territrial domain |
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Term
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Definition
| the numerical value represented by each dot in dot mapping, sometimes referred to as unit value |
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Term
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Definition
| ancillary data layers or maps that influence the placement of dots within the enumeration units |
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Term
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Definition
| the subjective response to the physical stimulus of the actual number of objects in a visual field; not the result of the conscious ativity of counting; number is underestimated reading dot maps |
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Term
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Definition
| the dot's function of representing geographical space |
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Term
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Definition
1. use point symbols for quantitative data
2. Symbol form consider size, shape, color, and the frequency of dots
3. works best for enumeartion area totals, dot locations, ancillary data and dot locations |
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Term
| Advantages of dot density map |
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Definition
1. easily understood
2. good way to display variations in spatial density
3. original data may be recovered from the map
4. more than one data set may be illustrated
5. GIS and mapping software implementation |
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Term
| Disadvantages of a dot density map |
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Definition
1. reader perception is not linear
2. GIS will randomize dots within enumeration units
3. ancillary data layers or imagery doesn't control dot placement
4. large ranges in data values aren't acceptable
5. practically impossible to recover original data values when them map is designed for optimum portrayla of relative spatial density |
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