# Shared Flashcard Set

## Details

Geog 416 Final Exam
Raster, Isoline, Data Scale, Data Classification
39
Geography
Undergraduate 4
11/16/2011

## Cards Return to Set Details

Term
 Isolines
Definition
 [image] vector representations of continuous data helpful in 3 dimensions
Term
 Isoline Creations
Definition
 created infinite numbers of points line drawn on interpolated values between points once drawn smooth   when points are few interpolate additional point value then interpolate isolines
Term
 Types of Isolines
Definition
 types of isolines = quantitative data types can be collected as points   many as specific names   Examples: isobath isocline isohips
Term
 Isoline GIS
Definition
 each line = 1 meter context lines = multiples of isolines
Term
 Rasters
Definition
 [image] spreadsheets row & columns = forms cells grid = rows columns = tessellations data unit = spatial (cell) --- x,y = implicit entity (object) info = explicity encoded each cells must have numeral value   all about numbers analytical modeling
Term
 Natural Surfaces   Raster
Definition
 natural world = continuous data ideal spatial model to illustrate these surface
Term
 Natural Surfaces Examples   Raster
Definition
 [image] Elevation Contours Rasters Surfaces symbolized low & high using color ramps elevation ramp colors - rising & lowering elevation
Term
 Color Ramps & Continuous Surfaces
Definition
 Color Ramps = stretched data stretched data organized values into 256 classes
Term
 Color Ramps & Continuous Surfaces Examples
Definition
 [image] Hillshades = create classic cartographic product a shaded relief map   use as reference layer, to help ppl orient themselves within map
Term
 Pseudo 3D Surfaces
Definition
 [image] flat surface appear 3D Seldom Digital animated to different perspectives
Term
 Data Scale
Definition
 nominal, ordinal, interval, ratio   numbers = data scale
Term
 Nominal Scale   Data Scale
Definition
 telephone numbers establish identity race = individuals have numbers to identify him not order & value
Term
 Ordinal Data Scale   Data Scale
Definition
 establish order 1st place, 2nd place, 3rd place   phone number is NOT ordinal
Term
 Interval Scale   Data Scale
Definition
 no absolute zero negative values   degrees 100oC -50oC
Term
 Ratio Scale Data   Data Scale
Definition
 has absolute zero no negative values   weight = 50 kg direct composition
Term
 Why we should care?   Data Scale
Definition
 different types of analysis different cartographic symbols different inappropriate values
Term
 nominal or categorical data   {data classifications}
Definition
 qualitative: ordered but without a measurable range   no absolute values
Term
 ordinal data   {data classifications}
Definition
 relative NOT absolute value deals with quantitative but without a measurable range using numbers label ordinal data often confusing
Term
 interval data   {data classificitions}
Definition
 quantitative: has NO absolute zero subtraction works NOT division class range = absolute zero negative numbers
Term
 ratio scale data   {data classifications}
Definition
 quantitative: absolute zero so both subtraction & division work no negative values in classification
Term
 Data Classification
Definition
 sorting or arranging entities into groups or categories   number of classes usually between 5 & 10, more likely 5 than 10   classifcation methods vary depending on data   ArcGIS = # of classification
Term
 Equal Interval   {data classification}
Definition
 [image] constant interval between classes # of observations will be different from class to class   Good = direct comparisons between different choropleth maps
Term
 Calculating Equal Interval
Definition
 subtract minimum from maximum divide result by # of classes result = width of each class add value with minimum value for first class   repeat until done
Term
 Quantile   {data classification}
Definition
 [image] equal # of observation per class same class = interval between classes = different
Term
 Calculating Quantile
Definition
 divide count of features by # of classes arrange features least to greatest divide into classes = matches result of division equation
Term
 Jenks - Natural Breaks   {data classification}
Definition
 [image] minimizes variance within a class by dividing classes in areas different sized class & different # of observations
Term
 Mean & Standard Deviations   {data classification}
Definition
 [image] classes = mean & deviations from the mean best if data displays a nominal distribution
Term
 Calculating Mean and Standard Deviation
Definition
 Calculate the mean of data Calculate the standard deviation of data Arrange your first class to straddle[stand] mean Then add classes at intervals of standard deviation both above and below the mean class
Term
 Quantile - 5 Classes using 7,1,18,20,6,14,19,13,21,25,2,23,1,15
Definition
 using 3 observation: (1,1,1) (2,2,6) (7,13,14) (15,18,19) (20,23,25)
Term
 Equal Interval - 5 classes using 7,1,18,20,6,14,19,13,21,25,2,23,1,15
Definition
 (1,1,1,2,2) (6,7) (13,14,15) (18,19,20) (23,25)
Term
 Cartogram
Definition
 diagram or abstract geographical to distorted proportionally value of an attribute NOT that useful Trade off between Area error and shape error   Hard to make a real shapes Do not use cartograms to show average values, per capita, values, etc People look what’s on the map but comparing to what’s in their head CANNOT show mean, average [image]
Term
 World Population {Cartogram}
Definition
 [image] Area scale accurately represents selected variable   Contiguity is maintained   Shapes should remain recognized   World population is useful but not as continuity
Term
 Bush and Kerry Cartogram
Definition
 [image]Look cool and artistic but hard to read   Election Count by counties NOT states
Term
 Types of Cartogram
Definition
 Contiguous Non - Contiguous
Term
 Contiguous {Cartogram}
Definition
 Maintained Recognized = shapes Area scale accurately selected   Advantages: Easy to read   Disadvantage: Distortion can confuse reader Shapes of internal numeration may recognition impossible Difficult to produce through commercial GIS software The circle population = contiguity [image]
Term
 Non - Contiguous {Cartogram}
Definition
 Not maintained Area scale accurately recognized selected   Advantage: Easy to construct GIS True shapes of enumeration units   Disadvantage: Separated No compact White spaces Do not convey continuous nature of geographical space Trade off between maintaining relative positive of enumeration unit and not overlapping [image]
Term
 Restrictions on Cartogram
Definition
 Shape quality: cartograms useless? some approximation of true shape can be achieved Each enumeration unit needs size, shape, orientation and contiguity… Least important = communication
Term
 Data Limitation Cartogram
Definition
 Data must be ratio Positive values in data sets with large range are problem. Negative values cannot be mapped Zero values eliminate the enumeration unit, creating map
Term
 Creating Cartogram
Definition
 Calculate total value for enumeration units based on single attribute   Compute proportional area of enumeration unit’s base on attribute value for each divided by total value   Draw, calculate and conform shapes and values
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