GEOG 328 Midterm I

Question 1

What is the definition of Spatial Analysis?

Answer 1

A subset of analytic techniques whose results depend on the spatial frame, or it will change if the frame changes, or if objects are repositioned within it.

Question 2

Components of Spatial Data:

What does Location refer to?

Answer 2

describes where a “thing” is in space

Question 3

Components of Spatial Data:

What does Attribute refer to?

Answer 3

Provides specific information about the thing. (non-geographic)

Question 4

What do X, Y & Z represent?

Answer 4

X & Y represent geographic location

Z represents elevation

Question 5

if data is spatial what can “z” also represent?

Answer 5

Attributes

Question 6

What are the components of Spatial Analysis?

Answer 6

1. Data manipulation
2. Exploratory Spatial Data Analysis
3. Spatial Statistical Analysis
4. Spatial Modelling

Question 7

What is a Vector Data Model?

Answer 7

A model that uses points, lines, polygons to represent spatial features or objects with a clear spatial location and boundary.

Question 8

What is a Raster Data Model?

Answer 8

A model that uses a grid to grid cell to represent a continuous field e.g. elevation, temperature.

Question 9

What can Spatial Analysis Reveal?

Answer 9

Patterns (visualizations) that are otherwise invisible in Data.

Question 10

What does IDW stand for?

Answer 10

Inverse Distance Weighted

Question 11

What did John Snow use to determine the causes behind how cholera spread in London

Answer 11

Spatial analysis of the wells allowed him to determine it was a waterborne illness stemming from an infected well source.

Question 12

What is a Spatial pattern?

Answer 12

A spatial distribution of objects (locations of people infected with a disease)

Question 13

What is a spatial process?

Answer 13

Spatial phenomena that results in a spatial pattern (mosquito infection and transmission)

Question 14

What elements make up a Point Pattern Analysis?

Answer 14

Only concerned with location, an indication of underlying spatial process (e.g. crime data)

Question 15

to conduct a successful point pattern analysis what elements must you have?

Answer 15

proper coordinates, correctly projected (preferably preserving distance), a study area which is objectively determined, proper event locations.

Question 16

What is Toblers 1st Law of Geography?

Answer 16

“Everything is related to everything else, but near things are more related than distant things.”

Question 17

What does SAC stand for?

Answer 17

Spatial Auto Correlation

Question 18

What is SAC?

Answer 18

The correlation of a Variable with itself in space.

Question 19

What does +SAC and -SAC generally mean?

Answer 19

\+SAC = Clustering
-SAC = Dispersion

Question 20

Examples where measuring SAC is useful?

Answer 20

Point Data - wells with attribute data
Line Data - accident rates in a highway network
Area Data - % of pensioners in a region

Question 21

What is used to measure SAC?

Answer 21

Moran’s I - measures the degrees of autocorrelation.

Question 22

What is an example of Linear Distance Decay?

Answer 22

noise levels along a transect perpendicular to a flight path.

Question 23

What is an example of Negative Exponential Distance Decay?

Answer 23

Decrease in rental storage patronage with distance from the facility

Question 24

When is SAC useful? When is Point Pattern Analysis useful?

Answer 24

SAC for when you’re looking to see if there is a cluster of a certain values (Z values)

PPA for analyzing the pattern alone

Question 25

why would you not want to perform a statistical analysis on data that has been auto correlated?

Answer 25

It can cause a false acceptance of the null hypothesis

Question 26

What is a First order Spatial Autocorrelation?

Answer 26

Spatial variations which occur when observations across a study region vary from place to place due to changes in the underlying properties of the local environment.

Question 27

What is a MAUP?

Answer 27

Modifiable Areal Unit Problem - When data are aggregated the location of the boundaries can significantly impact the results of statistical tests such as Moran’s I

Question 28

What is the Ecological Fallacy?

Answer 28

the belief that relationships observed for groups necessarily hold for individuals.

Question 29

What is the Boundary Problem?

Answer 29

Because spatial problems are generally unbounded and for study purposes we often impose arbitrary boundaries this can result in edge effects in the data that do not exist in space

Question 30

What is Primary Data?

Answer 30

Data which you have collected

Question 31

What is Secondary Data?

Answer 31

Data Which has been collected by someone else (found online, etc…)

Question 32

What are some considerations for primary data?

Answer 32

The accuracy of your data
What the sampling strategies were
Your Budget/time/site access

Question 33

What are some considerations for Secondary Data?

Answer 33

Is it out of date? What does the metadata look like? does the format of the data actually suit what im doing?

Question 34

What do GPS co-ordinates depend upon?

Answer 34

How we translate points from 3D -> 2D

The models we use to describe the earth (Ellipsoid / Geoid)

The measurements we use to reference our cooridiantes

Question 35

Why is the raw earth model shaped the way it is? what does it provide?

Answer 35

The effects of gravity cause the surface to be distorted. provides the Z value (elevation)

Question 36

What is an Ellipsoid? What does it provide?

Answer 36

Ellipsoid is a 3-D reference surface based on an ellipse and provides us our x/y cooridiantes

Question 37

What is a Datum?

Answer 37

Datum consists of information about the size and shape of the earth in conjunction with reference point data to better describe locations on the earth.

Question 38

What are Coordinates Systems?

Answer 38

A system used to register and measure horizontal and vertical locations on the earth.

Question 39

What are the 5 Projections? What do they Preserve?

Answer 39

Equal Area (Areas) 
Conformal (Angles) 
Equidistant (Distance)
Azimuthal (Directions)
Compromise (minimum errors)

Question 40

What are some of the main challenges with GPS accuracy?

Answer 40

Blocked signals (Urban Canyons)
Satelite Geometry
Multipath/Reflected signals
Ionospheric interference