Week 9: Vector analysis

Question 1

A goal for spatial analysis is to

Answer 1

Reveal patterns, trends and anomalies that might otherwise be missed

Question 2

Queries can be based on

Answer 2

Attributes or location

Question 3

Spatial data contains

Answer 3

1. Location information
2. Attributes
3. Metadata

Question 4

Goals of spatial analysis: Spatial analysisi combines both attrributes and locations of objects/features to

Answer 4

1. Transform raw data into useful information
2. Reveal patterns, trends, and anomalies that might otherwise be missed
3. Allow us to test “conventional knowledge” and/or hypotheses

Question 5

Analysis is considered spatial if the results depend on

Answer 5

The location of the objects being analyzed (move the objects and the results change)

Question 6

Queries, or data subsetting, involves

Answer 6

Turning raw data into information (tables, graphs, maps)

Question 7

Queries do not

Answer 7

1. Change existing data sets
2. Create new data by combining existing data sets

Question 8

Transformations

Answer 8

Create new objects and attributes based on simple rules

Question 9

Two types of proximity based transformations

Answer 9

1. Buffering
2. Joins

Question 10

Characteristics of buffering

Answer 10

1. Divides space into discrete areas of influence
2. Positive and negative
3. Multiple rings
4. Variable width linked to attribute

Question 11

Two types of joins

Answer 11

1. Attribute join
2. Spatial join

Question 12

Attribute join characteristics

Answer 12

1. Used to append the fields of one table to another table based on a common field
2. The common field is common data / can have different names
3. Does not create a new dataset / it just holds the attribute connection in memory

Question 13

Spatial join characteristics

Answer 13

1. Used to append the field from one layer to the other based on geogrpahic proximity
2. Can be based on spatial coincidence (intersect), touch, or within a specified distance
3. Creates a new dataset with the combined attributes

Question 14

What is a vector overlay (spatial join)

Answer 14

Combining layers to explore the spatial relationships between their features

Question 15

Overlay issues

Answer 15

1. Spurious polygons (sliver polys)
2. Complexity of output map layers
3. Dissolving adjacent polygons (spatial aggregation) to solve these issues

Question 16

Why do we need to show our work through a flow chart

Answer 16

1. Repeatability (good scientific method)
2. Identifying errors in analysis
3. Coming back to the work to tweak something
4. Naming conventions are important