Gis Exam 3

Front 1

When you take a layer of data, perform an operation, and come out with a new layer, what process have you performed?

Back 1

Basic Spatial Analysis

Front 2

Name in order the 3 main steps to Basic Spatial Analysis.

Back 2

1. Input

2. Spatial Operation

3. Output

Front 3

When one input creates many outputs, what has happened?

Back 3

basic spatial analysis

Front 4

Name 3 operations involved with Exploration

Back 4

1. Descriptive Statistics

2. Graphing/Charting

3. Attribute Queries

Front 5

What operations are involved with Attribute Queries?

Back 5

1. set algebra (<,>,+,-)

2. boolean algebra (AND, OR, NOT)

Front 6

What operation is involved with Spatial Selection?

Back 6

spatial queries

Front 7

Spatial selection involves operations such as spatial queries. What can you do with spatial queries?

Back 7

1. Cursor or Graphic select

2. Select by spatial relationship (Proximity / Adjacency, or Containment)

3. Intersection

Front 8

Spatial Queries are based on

Back 8

location

Front 9

By choosing 'Containment' when selecting by spatial relationship, what are you essentially selecting?

Back 9

Items that fall completely within a selected space.

Front 10

How can you make a selection based on both spatial and non-spatial attributes?

Back 10

1. Dissolving

2. Buffering

3. Overlay

4. Other map manipulations

Front 11

Which spatial selection aggregates features based on specific attributes, essentially combining like-features on a data layer and removing boundaries between data if the data shares boundaries?

Back 11

Dissolve

Front 12

Describe the Dissolve function of Spatial Selection

Back 12

Combines like-features on a data layer and removes the boundaries between data when it shares outer boundaries.

Front 13

Describe an example of how you might use the Dissolve spatial selection operation.

Back 13

A map depicts climate regions of the US. Dissolve removes the state boundaries and keeps boundaries between only the different climate regions.

Front 14

Which spatial selection operation finds an area within a specified distance around a feature?

Back 14

Buffer

Front 15

Describe the spatial selection operation: Buffer

Back 15

finds an area within a specified distance around a feature.

Front 16

look up variable distance buffer

Back 16

lecture 7

Front 17

Which spatial selection operation essentially takes 2 input layers and creates one output layer?

Back 17

Overlay

Front 18

Describe how the spatial selection operation Overlay works.

Back 18

combines different data layers, both spatial and attribute data, to create a result layer.

Front 19

What condition must the Overlay operation meet to be performed?

Back 19

all data layers must use a common coordinate system

Front 20

What 2 different options do you have when performing an overlay?

Back 20

1. union

2. intersect

Front 21

Describe a Union overlay

Back 21

Combines all of 1st and 2nd layer, regardless if they overlap.

(Think "OR")

Front 22

Describe an Intersect overlay.

Back 22

Only keeps areas that are shared between all input layers.

(Think "AND")

Front 23

Name a map manipulation that extracts info from a different layer to create a "cookie cutter."

Back 23

Clip

Front 24

Basic raster data is a

Back 24

grid of pixels

Front 25

Is raster data continuous or non-continuous?

Back 25

continuous

Front 26

What type of data does raster data NOT recognize?

Back 26

entity-attribute

Front 27

Raster data recognizes only which type of data?

Back 27

spatial

Front 28

What is a disadvantage to raster data?

Back 28

database is much larger

Front 29

Name the 7 Raster GIS Conventions

Back 29

1. Map layer

2. Square mesh

3. Resolution

4. Orientation

5. Zone

6. Class

7. Value

Front 30

What is the most important quality to remember about raster map layers?

Back 30

each layer has a different theme (such as land cover, etc.)

Front 31

What is the square mesh component of raster data?

Back 31

the grid composed of rows and columns

Front 32

Each cell of the square mesh contains a

Back 32

numeric value

Front 33

What does resolution determine?

Back 33

what size the grid cell is

Front 34

What is a raster zone?

Back 34

a group of continuous pixels with the same value

Front 35

What is a raster class?

Back 35

a group of zones

Front 36

Describe raster values.

Back 36

Every cell must have a numeric value. There can be no empty space with no value.

Front 37

What type of image has the most values?

Back 37

photographic images

Front 38

What is the "Mixed Pixel Problem"?

Back 38

Some pixels may contain information with multiple values, but the cell can only have one numeric value.

Front 39

Name and describe 3 ways to alleviate the Mixed Pixel Problem

Back 39

1. centroid: pick the value that's in the center of the cell

2. transverse: place a line going thru the middle of the cell and choose the value the line crosses most

3. percentage: pick the value that makes up the highest percentage of the cell

Front 40

Name the 2 types of Raster GIS data layers

Back 40

1. Image

2. Gridded Area-Class Map Layer

Front 41

Look up Image vs. Gridded Area-Class Map Layers

Back 41

pp lecture 8

Front 42

List the 3 main Raster analytic operators

Back 42

1. Reclass / Recode

2. Overlay

3. Distancing

Front 43

Why might you choose to Reclass/Recode?

Back 43

to separate a pixel from the rest

Front 44

Which raster analytic operator changes the value of a pixel?

Back 44

reclass/recode

Front 45

What raster analytic operator is the same idea as "Buffer," but for raster?

Back 45

distancing

Front 46

What is better for cartography - raster or vector?

Back 46

vector

Front 47

How many area class values can you have?

Back 47

only 7

Front 48

Name the 4 types of terrain analysis

Back 48

1. DEMs (Digital Elevation Models)

2. Derivative surfaces and functions

3. applications using elevation models

4. TINs (Triangulated Irregular Networks)

Front 49

Name 3 ways to generate digital elevation models (DEMs)

Back 49

1. photogrammetry

2. scanning

3. spatial interpolation

Front 50

What can you determine using DEMs and DEM derivative surfaces?

Back 50

1. drainage basins and watersheds

2. drainage networks and channels

3. peaks, pits, and other landforms

Front 51

What can you model using DEMs and DEM derivative surfaces?

Back 51

1. hydrologic flow

2. forest fires

Front 52

How do DEMs determine drainage networks?

Back 52

Use algorithms to determine the flow direction using either D4 or D8 movement

Front 53

LEARN AND UNDERSTAND D4, D8 MOVEMENT

Back 53

lecture 10

Front 54

Name 9 attributes that can be computed from DEMs

Back 54

1. elevation

2. slope

3. aspect

4. verticial profiling

5. watershed analysis

6. ridge

7. wetness index

8. viewshed

9. surface curvature