Vector analysis

Question 1

What are the 3 parts to a query?

Answer 1

Field name ex. volume
Relational operator (bigger than, less than, equal to) ex. greater
value ex. 250m3/ha

Question 2

What are boolean operators?

Answer 2

used to carry out a complex query
-And
-Or
-Not
to refine search

Question 3

What is the arithmetic calculation feature?

Answer 3

Applies a formula to a numeric field (similar to excel but different interface)

Question 4

What is a the statistics function?

Answer 4

provides a temporary pop up table with typical statistical parameters and plots data in a histogram.

Question 5

What is the function of the summarize feature?

Answer 5

creates a data table that you control the field output of. table is permanent.

Question 6

What are the 2 options when you right click a field name?

Answer 6

Summarize or Statistics

Question 7

What are the data classification schemes?

Answer 7

• natural break
• quantile
• equal interval
• user defined

Question 8

What are the max number of classes you would display on a map?

Answer 8

5-7 due to color overload

Question 9

What must you ensure that you do when relating the attribute table to outside tables in arcGIS?

Answer 9

• You must make sure that you are in the GIS attribute table when you make the join or link.

Question 10

What is the euclidean distance function?

Answer 10

(Straight line distance)

Question 11

What does geometric distance function give you?

Answer 11

line length (perimeter)

Question 12

How would you calculate area?

Answer 12

use the geometric area function

Question 13

What is important to remember about overlays and area?

Answer 13

Do not trust the area after you have performed an overlay

create your own column called ha. and use calculate area function.

Question 14

What is the select by location query?

Answer 14

• feature selected based on relation to other features by comparing two themes.
• Target layer - features selected
• outside source layer - basis for selection
• ie. Within a distance of, within another feature.

Question 15

Some relationships

Answer 15

• intersect
• contain
• within a distance of (within a buffer)

Question 16

What is a buffer? **

Answer 16

• creates a new data layer

- creates polygons defined by a cerrtain distance from select features. (ex. wildlife tree buffer)

Question 17

What are the 3 buffer types?

Answer 17

• single (simple) buffer
• multi rings
• variable widths - defined by values in field (fish streams vs non fish)

Question 18

What is the purpose of the dissolve feature when overlapping buffers?

Answer 18

merges the overlapping buffers into one (forester should use this function)

Question 19

What is the point of an overlay?

Answer 19

• combine 2 layers
• creates a new data layer
• both linework and attributes

Question 20

What are the 5 types of overlays?

Answer 20

Clip
Intersect 
Union
Update
Erase

Question 21

Describe the “clip” method of overlay

Answer 21

• Area defined by the clip overlay theme
• 2 map layers are combined to Give a mini version of the original map
  ie. what forest is contained within a cutblock (input “dough” output “cookie”.)

Question 22

Describe the intersect type of overlay

Answer 22

• Area displayed is where the 2 maps overlap
• table contains all fields from both themes
• ex. landowner and forest

Question 23

Compare clip and intersect

Answer 23

• similar on spatial side
• clip only displays attribute data from the input (cookie dough) map
• intersect contains attribute data from both maps

Question 24

What is the union method of overlay?

Answer 24

• area is the total area of both (= COMBINED AREA = OR)

- table contains fields from both themes

Question 25

What is the difference between intersect and union?

Answer 25

• intersect only uses coincidence space

- union keeps all space from both maps

Question 26

What is another term for query?

Answer 26

select by attribute

Question 27

What is the update overlay type?

Answer 27

• updates features
• fields in both layers have to match
• ex. new cutblock supercedes forest theme

Question 28

What is the erase overlay type?

Answer 28

Polygons from an erase layer eliminate an area from the input theme. (overlay and eliminate)
ex. part of cutblock expropriated for parkland.

Question 29

What is the difference between append and merge?***

Answer 29

• Merge: Combines 2 layers to produce a new combined area

- Append: adds a layer to an existing layer

Question 30

Spatial Join ***

Answer 30

Creates a new layer containing features from the target layer and attributes from both layers. Based on co-incident space.
ex. plots in polygons.
good for 1:1 or M:1