Exam 2 Flashcards

1
Q

Spatial analyses

A

-applied to solve a spatial problem or answer a spatial question

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2
Q

Most spatial analyses require the use of

A
  • spatial operations
  • spatial functions
  • spatial modules
  • spatial tools
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3
Q

Cartographic model

A

-chain or sequence of steps to produce desired output

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4
Q

Spatial operations

A
  • local operations
  • neighbor operations
  • global operations
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5
Q

local operations

A

-use data from individual cell or feature to derive output

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6
Q

Neighborhood operations

A

-use date from neighboring cells or feature to derive output

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7
Q

Global operations

A

-use data from all cells or features to derive output

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8
Q

Dissolve

A
  • create a new feature that removes boundaries in the old feature based on a field in the attribute table
  • best to have binary data
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9
Q

classification functions

A

-assigning new values to features or cells based on some rule (vector or dissolve or reclass)

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10
Q

Local operations steps

A
  • selection (query)
  • classification
  • overlay
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11
Q

Overlay analysis

A
  • taking two or more input layers and extracting info based on where features do or do not overlap
  • multiple criteria identify suitable sites
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12
Q

Neighborhood operations steps

A
  • distance
  • buffer
  • adjacency
  • interpolation
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13
Q

Global operations steps

A
  • statistical summary

- ranking

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14
Q

Binary images

A
  • all values are either 0 or 1

- 0 meets doesn’t meet criteria and 1 means it does

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15
Q

Map algebra

A

-using simple mathematical operations while overlaying two or more images

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16
Q

Proximity distance functions

A
  • used for developing buffers surrounding points, lines, or polygons
  • most powerful and common spatial analysis tool
  • distance based on Pythagorean formula
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17
Q

Cost surfaces

A
  • develop a layer that quantifies the cost to travel across the cell
  • cost can be monetary of it could just represent a friction surface
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18
Q

Natural resource management example of cost surfaces

A
  • locating the optimal location of laying out a new road

- forecasting the spread of a forest fire

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19
Q

Raster grid

A
  • Digital elevation model
  • digital surface model
  • digital terrain model
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20
Q

Sources of digital elevation data for spatial analysis

A
  • ground survey
  • digitizing contour maps
  • completely digital photo contours
  • laser based elevation mapping
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21
Q

LiDAR

A
  • light detecting and ranging
  • active remote sensor
  • aerial and space based platforms
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22
Q

QL1

A

-Lidar generated with highest point density
-penetrating forest canopy, geological changes, aviation
and infrastructure

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23
Q

QL2

A

-Lidar quality by less demanding
-coastal zone mgmt, conservation planning, wetlands,
soils

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24
Q

QL3

A
  • Typical Lidar acquisition

- General topographic mapping, floodplain work

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25
Q

QL4

A
  • Stereo Aerial images

- General topographic mapping, Orthoimage production

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26
Q

QL5

A

-Aerial base RADAR
-Course general topographic mapping but helpful in
difficult climatic areas (Alaska)

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27
Q

Single image relief displacement

A

-makes buildings look tilted when they’re straight

28
Q

Relief displacement

A

-greater displacement when further away from photo center

29
Q

Stereo parallax

A

-relative shift in position of object with change iin observe location

30
Q

Parallax bar

A

-tool to assist in finding heights of objects and points of equal elevation

31
Q

LiDAR discrete

A

-lower energy pulses, very high pulse density/sqr meter, tree canopy penetration, many returns recorded

32
Q

LiDAR waveform

A

-higher energy pulse, single wide angle pulse, return continuously

33
Q

Types of terrain analysis

A
  • slope
  • aspect
  • contours
  • Hydrologic functions
  • viewshed
34
Q

Aspect is used to

A
  • define direction water will flow
  • amount of sunlight a site will receive
  • portion of landscape visible from any viewing point
35
Q

Aspect is

A

-the steepest downhill direction

36
Q

Slope formula

A

-the formula with arctan, sqaure root of x + y

37
Q

Aspect formula

A

-has arctan but square root of y/x instead

38
Q

Contour function

A
  • Reverse process of creating DEMs
  • output vectors are isolines
  • can be used with other types of continuous data other than elevation
39
Q

Watershed delineation

A
  • conditioned DEM
  • Flow direction
  • Flow accumulation
  • Stream threshold
40
Q

Viewshed

A

determination of what can be seen from a set of target viewpoints

41
Q

Sampling patterns

A
  • systematic (uniform space)
  • random (no pattern)
  • clustered (multiple groups)
  • adaptive (all around one spot and branch off)
42
Q

Spatial interpolation

A

-estimate values at unsampled locations using only measured values for variable of interest

43
Q

Morans 1 statistic

A

-assumes the null hypothesis that attributes are randomly distributed or the observed value is chance

44
Q

Kernel mapping

A

-mapping the density distribution based on attribute data from sample points

45
Q

Steps of kernel mapping

A
  • collect data
  • select kernel density function
  • select bandwidth
46
Q

GNSS

A
  • provides positioning and clock time to the terrestrial user
  • GLONASS, Galileo, Compass, NAVSTAR or GPS
47
Q

GLONASS

A
  • global navigation satellite system
  • Russian
  • consists of 24 satellites
48
Q

Galileo

A
  • created by European union

- 20 of a planned 30 satellites in orbit

49
Q

NAVSTAR

A
  • Navigational signal time and ranging (GPS)

- BLOCK 1 and 2 activated, BLOCK 3 should be activated this year

50
Q

Satellite segment

A
  • 20,200 km orbits

- each satellite transmits microwave signals on two separate channels (L1 and L2)

51
Q

Control segment

A

-used to observe, maintain and manage the GPS satellites

52
Q

User segment

A

-receive data from satellites and processes data to provide locational info

53
Q

How GPS satellites work

A

-carrier signals are modulated to produce coded signals

54
Q

Almanac data

A

-general location for all satellites

55
Q

Ephemeris data

A
  • precise position info of the satellite

- clock and location constant updates from Ground Segment

56
Q

Location determination of GPS

A
  • based on accurate time measurements

- lag time permits calculation of distance between receiver and satellite

57
Q

Positional uncertainty

A
  • Range uncertainty
  • Atomspheric (least) and Ionospheric delays (greatest)
  • Reciever clock delays
  • Orbital errors
  • Signal multipath
  • satellite geometry
58
Q

How to get more accurate GPS data (point averaging )

A

-position the receiver over a point for a period of time and each epoch is recorded, then positions are averaged

59
Q

WAAS

A
  • Wide area augmentation system
  • makes GPS data better
  • uses 3 segments (ground, space, user)
  • originally developed for FAA applications
60
Q

NAVSTAR 3 segments

A

satellite, control, user

61
Q

Ground segment of WAAS

A
  • 25 in US
  • Data relayed to WAMS via land lines
  • WAMS computes error
62
Q

Space segment WAAAS

A
  • 3 communication satellites
  • recieve signal from WAMS
  • broadcast info back to earth
63
Q

GPS applications

A
  • Navigation
  • Field digitizing and surveying
  • Tracking
64
Q

Things to know when using a GPS reciever

A
  • Need to set Datum and coordinate system

- dump data and clear tracks

65
Q

Differential GPS

A

-two or more recievers
-base (known point)
-Rover (unknown point)
Distance <100km