gis

Question 1

what is a buffer zone

Answer 1

based on the concept of proximity, at its simplest buffering creates two areas, one within a secified distance of a selected feature (value=1) and the other outside (value=0) a specified distance of a select feature (point, line or polygon)

Question 2

what are some uses of buffer zones

Answer 2

protection zones, suitability zones, inclusion zones, sampling methods, neutral zones

Question 3

what’s an overlay operation

Answer 3

combine the geometries and attributes of two features to create a new output.

Question 4

what are the 4 overlay options and their purpose

Answer 4

Union-all of the data
Intersect- only those that intersect lol
Symmetrical difference- only 1 not both
Identity- All of A and only what B is in A

Question 5

what is the boolean connectors

Answer 5

AND- intersect
OR- Union
XOR- symmetrical difference

Question 6

what are the two types of distances

Answer 6

euclidean (straight line)
Manhattan (right angles)

Question 7

what is shape measurement

Answer 7

how compact a polygon is perfect 1.0 is circle

Question 8

what are the three clustering pattern analysis

Answer 8

clustered
uniform
random

Question 9

what is Nearest neighbour analysis

Answer 9

the test that determines, clustered, uniform or random

Question 10

what is ripples k function

Answer 10

a spatial statistic that determines whether a point pattern is random, regular or clustered over a range of distance. looks at many neighbours

Question 11

what is spatial autocorrelation

Answer 11

a spatial statistic that measures the relationship among values of a variable according to the spatial arrangements of the values (comparing weights)high near high

Question 12

What is G-statistic

Answer 12

a spatial stat that measures the clustering oh high and low values in a data set (hot spot and cold spots)

Question 13

what’s an analysis mask

Answer 13

Limits analysis to cells that do not carry the cell value of “no data” e.g. could limit analysis to only certain cells that contain podzol soils, or elevation over 1000m asl

Question 14

what is reclassification

Answer 14

raster. simplify cell values. 2 and 3 is forest reclassify to just 2 is forest

Question 15

what are neighbourhood operations

Answer 15

involves a focal cell and a set of its surrounding cells. The surrounding cells are chosen for their distance and/or directional relationship to the focal cell.

Question 16

what is a zonal operation

Answer 16

a raster data operation that involves groups of cells of same values or like features.

Question 17

what’s GIGO

Answer 17

garbage in garbage out

Question 18

define quality

Answer 18

often simply defined as the degree of excellence

Question 19

define error

Answer 19

the physical difference between the real world and the GIS facsimilioe

Question 20

difference of accuracy and precision

Answer 20

the extent to which an estimated data value approaches its true value (accuracy)
the recorded level of detail of your data (precision)

Question 21

define Bais

Answer 21

systematic variation of data from reality

Question 22

define spatial resolution error

Answer 22

describes the features in a dataset that can be displayed or mapped (scale errors)

Question 23

define generalisation errors

Answer 23

is the process of simplifying the complexities of the real world to produce scale modelsand maps (trees bushes as vegetation)

Question 24

define completeness error

Answer 24

a complete dataset will cover the study area and the time period of interests in its entirety (how complete the dataset is)

Question 25

what 2 elements do all models have

Answer 25

have a set of selected spatial variables
there are functional or mathematical relationships between the variables

Question 26

what are the 4 models

Answer 26

Descriptive and prescriptive
deterministic and stochastic
dynamic and static
deductive and indicutive

Question 27

3 steps to a model

Answer 27

1. define the goals of a model
2. form a conceptual diagram of variables
3. implementation and calibration testing accuracy and refining

Question 28

what is model validation

Answer 28

asses the models ability to predict under conditions that are different from those used on the calibration phase

Question 29

how does his help modelling

Answer 29

1. can function as database management tool
2. models can flip raster and vector
3. can be moddeled itself then can export

Question 30

what’s the binary model

Answer 30

a GIS model that uses logical expressions to select features from a composite feature layer or multiple rasters.( yes no)

Question 31

limitations of map overlays on models

Answer 31

1. are difficult to comprehend when more than four or five factors are involved
2. do not allow for the fact that variables may not be equally important
3. the descisions about threshold values are important. E.g.if population density is a criterion for locating an area, would the threshold be 400 or 427 or 530 or person/km squared

Question 32

what’s a siting analysis

Answer 32

siting analysis- determines if a unit area meets a set of selection criteria for locating e.g. a landfill, nuclear power plant, grocery store

Question 33

what is a index model

Answer 33

calculates the index value for each unit area and produces a ranked map based on the index values. Similar to binary in that both involve multicriteria evaluation and both involve overlay operations

Question 34

what is a regression model

Answer 34

relates a dependant variable to several independent (explanatory) variables in an equation, which can then be used for prediction or estimation

Question 35

what is a compatibility

Answer 35

data sets should be developed using similar methods of data capture, storage,manipulation and editing

Question 36

what is a applicability

Answer 36

the appropriateness or suitability of data for a set of commands, operations or analyses

Question 37

define a conceptual error

Answer 37

originate from the way we perceive and model the real world

Question 38

define operational error

Answer 38

are those errors introduced and propagated during the digitization process

Question 39

what are the four common manual errors

Answer 39

psychological errors (finding true centre)
Physiological errors (involuntary muscle spasms which creates random displacements)
Line thickness
Method of digitising