Shared Flashcard Set

Details

GIS Final
Final Test
46
Other
Graduate
05/03/2013

Additional Other Flashcards

 


 

Cards

Term
List the three types of change we map
Definition
Location- tracking map/position of features over time
Values or Magnitude- can create difference map/can subtract values or express values as % change
Character- land use or cover change over time
Term
This function allows us to see change in animation form
Definition
Time Slider
Term
In geographic distribution maps it is important the data is A)unprojected B)projected.
Definition
B)Projected
Term
What two tools are used most frequently to measure geographic distributions?
Definition

Mean Center

Central Feature

Term

Where are mean center and central feature located in the toolbox?

 

Definition
ArcToolbox>Spatial Statistics>Measuring Geographic Distributions
Term
What does mean center do?
Definition
Calculates the center of a distribution
Term
What does central feature do?
Definition
Identifies the most centrally located feature in a point, line, or polygon feature class.
Term
Define a discrete raster?
Definition
discrete rasters represent points, lines, polygons (feature class codes  - integer values)
Term
Define a continuous raster
Definition
continuous rasters represent surfaces (unique decimal values for each cell)
Term
What are the different ways a discrete and continuous raster can be symbolized?
Definition
recognize that a classified continous raster elevation model can appear the same as a discrete hypsography raster
Term
How do you reclassify a continuous raster into a discrete raster?
Definition

ArcToolbox>Spatial Analyst>Reclass>Reclassify

 

In the Reclassify workspace, use continuous raster dataset in to the input raster box. 

Choose reclass field (value)

Click reclassify button

Under classification click method dropdown and choose equal interval

[image]

Term
What is a value attribute table?
Definition
Raster datasets that contain attribute tables typically have cell values that represent or define a class, group, category, or membership
Term
How do you convert a raster to features?
Definition
ArcToolbox>Conversion Tools>From Raster>From here there are several options (From Raster to Polygon, Raster to Polyline, etc.)
Term
How do you convert features to raster?
Definition
  • Any feature class (geodatabase, shapefile or coverage) containing point, line, or polygon features can be converted to a raster dataset.

  • The input field type determines the type of output raster. If the field is integer, the output raster will be integer; if it is floating point, the output will be floating point.

  • This tool always uses the cell center to decide the value of a raster pixel. If more control over how different types of input feature geometries are to be converted, please refer to the respective specific conversion tools: Point to RasterPolyline to Raster, and Polygon to Raster.

  • This tool is a complement to the Raster to PointRaster to Polyline, and Raster to Polygon tools, which convert a raster to different types of feature dataset geometries.

Term
Projected vs. Unprojected Rasters
Definition

When using an improperly projected DEM or other raster, other calculations (such as slope, aspect, visibility and any processing tasks that depend upon both vertical and horizontal linear units of measurement) can output wildly inaccurate results.


Essentially, alnalysis of unprojected rasters will lead to incorrect results. 

 I'm assuming he will have the picture of Texas projected and/or unprojected and we will have to identify projected or unprojected

 

Term
How are the length of a degree of latitude and longitude changed with latitude
Definition

As we move up in latitude a degree is stretched by latitutde. Alaska appears larger N-S because of this effect.

 

I think I have this right, but y'all check it out

Term
1 degree = X meters
Definition
112,000 meters... I think
Term
When cell size is specified as 0.00027777778, what is the approximate cell size in meter?
Definition
30 meters... I think
Term
Whatways can terrain be represented?
Definition

Vector Lines (contours)

Polygons (hypsography)

Continous Raster 

Discrete Raster

TIN

Term
Define a DEM in detail
Definition
Digital Elevation Models are continous elevation model (raster) - elevation value assigned to each grid cell
Term
What dataset is always rectangular and you can use NoData values to alter the sahape of the display?
Definition
DEM
Term
Where can you locate information about a DEM in ArcMap?
Definition
Layer Properties Dialog Box
Term
List some important things to remember when working with DEMs
Definition

Elevation Units

Coordinate System

Horizontal Datum

Vertical Datum

Grid Cell Size

Term
If a DEM is unprojected how is the grid cell expressed (mesurement)?
Definition
decimal degrees
Term
If a DEM is projected, how is it expressed (measurement)?
Definition
Meters or Feet
Term
When describing GCS DEMs, how do we refer to the resolution (grid cell size)?
Definition
arc seconds
Term
How do you convert arc seconds to meters?
Definition
I don't have my notes! Can you two please fill this one in?
Term
How do you set the z value for creating hillshades in projected datasets?
Definition
Again I don't have my notes. Can you please fill this in?
Term
How do you set the z value for creating hillshades in unprojected datasets?
Definition
No notes! Please fill in.
Term

How are TIN elevation models usually created?

 

Definition

From raster DEMs

3D Analyst Tools>Conversion>From Raster>Raster to TIN

Term
When creating a TIN, what determines how detailed the TIN layer is?
Definition
The Z-tolerance
Term
What does the TIN use to model terrain?
Definition
Irregular shaped triangular facets
Term

Each triangle in a TIN has what to map terrain?

 

Definition

3 nodes with elevation values (each node has an x,y, and value)

The 3 nodes are then connected by lines to form triangles

Term
The x, y, and z coordinates of the nodes in a TIN has a defined ______, and _________.
Definition
Aspect and slope
Term
How do you enable and add the 3D Analyst Toolbar?
Definition

Enable:

in ArcMap, select Extensions from the Tools pull-down menu to open the Extensions dialog box. 

Check the 3d Analyst box (enables extension)

Add:

Select 3D Analyst from the View pull-down menu (adds extension)

Term
The buttons on 3D Analyst can create ______, _______, _______, and _______.
Definition
graphic contours, a steepest path, a line-of-sight, and profile graphs (profile graphs can be created from a straight line or segmented curve).
Term
ArcScence is included with which extension?
Definition
3D Analyst, and can be launched from a button on the 3D analyst toolbar
Term
The ArcScene interface is designed for viewing ______, _______, and creating ________.
Definition
3D terrain models, 3D features and creating animations
Term
Most often ArcScene is used to create what?
Definition
3D fly-throughs of a terrain model  (or imagery fraped terrain).
Term
The underlying terrain model in ArcScene can be either ______ or ______.
Definition
Raster DEM or TIN elevation model
Term

In ArcScene, _______ _______ are used from the raster DEM or TIN to extrude the terrain into a 3D model.

OR 

the same can be used from a raster or TIN can be used to extrude an inmage into a 3D model

 

Definition

Base Heights

 

Term
How do you emphasize terrain in ArcScene?
Definition
vertical exaggeration can be set in the Scene layers properties
Term
ArcScene can also be used to visualize 3D features overlaid on a terrain model. Explain How.
Definition

3D features assigned "base height" from raster DEM or TIN elevation model

3D features then extruded based upon a z attribute value

 

Term
ArcScene can also be used to create animations. List them:
Definition

animations of a fly-through

visulization of a time-series data

animations can be saved as video files (.mpg or .avi files)

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