First Test Oct 6 Flashcards

(51 cards)

1
Q

GIS refers to?

A

the hardware and software required to store spatial coordinate information for features called attributes

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2
Q

GIS data format is a …

A

collection of data points, lines, and polygons

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3
Q

annotation

A

text/labels on maps

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4
Q

choropleth maps

A

use light to dark shades of a particular color to indicate the relative number of a quantitative feature

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5
Q

dot density map

A

point data that is interpolated to create a continuous map coverage

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6
Q

continuous data

A

aka rastor data. a quantity that exists over the entire map area; always present; changes in value from place to place - elevation, precipitation, temperature; represent a measurement that occurs everywhere; thousands or millions of potential values; few adjacent cells have same values

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7
Q

vector model

A

features are stored as a series of X-Y coordinates in a rectangular coordinate system.

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8
Q

features can have ___ geometry shapes

A

3; points, lines, and polygons

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9
Q

feature class

A

collection of similar objects with the same attributes, stored as a single unit

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10
Q

a small scale map :

A

large denominator shows a large area

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11
Q

a large scale map

A

small demonintaor shows small areas

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12
Q

it is important to distinguish between ? and ?

A

source scale and map scale

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13
Q

precision

A

number of sig figs in a measurement

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14
Q

metadata

A

contains information about data that people need to understand the data and evaluate its quality. should be provided with every data set distributed to the public; advised for in-house data as well

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15
Q

topology

A

describes the spatial relationships between features - adjacency, connectivity, overlap, and intersection

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16
Q

logical consistency

A

describes how well the features mimic the real world situations; usually confined to testing for topology errors

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17
Q

RGB color model

A

each primary color brightness is indicated on a scale of 0 (black) to 255 (light)

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18
Q

HSV color model

A

hue represents the color on a scale of a 0-360 (color wheel); saturation represents the intensity of the color (0-100); value represents the brightness of the color (0-100)

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19
Q

CMYK color model

A

is considered to be a “subtractive” model as the colors are removed from white light

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20
Q

categorical data

A

may be text or numeric, portrayed with a unique values map

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21
Q

ordinal data

A

is a type of categorical data based on either quantitative or qualitative data; use a unique values map with a single hue color scheme

22
Q

ratio data

A

places values along a regular scale with a meaningful zero point

23
Q

interval and ratio data must

A

be divided into classes before mapping

24
Q

quantities data

A

are mapped using variations in symbol size, thickness, and hue

25
quantile classification
puts the same number of features in each class - best used when data is uniformly distributed
26
standard deviation classification
compares values close to and far from from the mean - best used when data is normally distributed as a bell curve
27
geometrical interval classification
multiples each class range by a constant - best for visualizing strongly skewed or logarithmically increasing data
28
minimizing Modifiable Areal Unit Problem
normalizing (dividing) data by a suitable field allows data patterns to emerge
29
visual Modifiable Areal Unit Problem
large polygons dominate map
30
layer files
easy way to transfer the same symbology to multiple maps of projects
31
otyles
set of symbols stored together; viewed and selected on symbology pane
32
discrete data
objects such as roads or land use polygon; take on relatively few values; adjacent cells often have same values; values may change abruptly at boundaries
33
five steps of map design
select, arrange, symbolize, review and edit
34
visual center of a page is about...
5% higher than the geometric center
35
elements of a map
data frames, title, dynamic text: spatial reference, text scale, RF scale; inserted text, north arrow, scale bar, legend, grid lines, neat lines
36
map grids
longitude and latitude marks around the map frame, show x-y coordinates, index grids show
37
desirable map properties
conformal (shapes accurate); equal area ( areas correct ); equidistant ( distances accurate); azimuthal (directions accurate)
38
no map projection can...
preserve both correct area values and accurate shape of features; can't have conformal and equilibrium at same times
39
unprojected geographic coordinate system
based on spherical globe coordinates; degrees of latitude and longtitude
40
projected coordinate system (PCS)
converts spherical coordinates to planar, set of math equations, projects 3D coordinates to 2D map
41
geoid
is defined by gravity measurements that have the same value everywhere
42
ellipsoid (spheroid) represents..
local reference for elevation ellipsoid is defined by length of axis: major and minor axis that represent longer and shorter radii of ellipsoid
43
datum
to minimize the discrepancy between the geoid and ellipsoid a datum is defined; shifts the ellipsoid relative to the geoid to achieve a best fit between the two
44
local datum
optimizes the shift for the best fit at a particular location; optimized for a country or continent or local area
45
geocentric or world centered datum..
optimizes the fit for the entire earth
46
datum transformations
converting one datum to another requires specialized fitting - several methods available; converting datums should be done only when necessary
47
types of geometric projections
cylindrical, conic, azimuthal
48
projection parameters
a projection is customized to work for the map region by setting parameters; central meridian, standard parallels, latitude of origin; false easting and north easting
49
standard parallels
occur where the projection surface touches the ellipsoid; a tangent projection has one standard parallel; a secant projection has two standard parallels; parallels are lines of no distortion
50
false easting and northing:
arbitrary values added to x and y values ensures that all coordinate numbers are positive
51
state plane projection system
states divided into one or more zones identified by a unique FIPS ( Federal information processing standard)