Analyzing Spatial Data

1
Analyzing Spatial Data

• Define the problem.
• Identify the data.
• Plan the analysis.
• Prepare the data.
• Execute the analysis.
• Evaluate the results.

2
Analyzing Spatial Data

• Set up the analysis environment.
• Specifying an extent.
• x,y coordinates for the bottom-left and the
  top-right corners.
• Default is the intersection of your input data.

3
Analyzing Spatial Data

• Set up the analysis environment.
• Cell size.
• Largest of the input data, unless you change it.
• Making it smaller will involve interpolation.
• Working directory.
• Where the results go, unless you specify.
• C\temp.
• Create an analysis mask, if necessary.

4
Analysis Toolbox

• Extracting GIS data.
• Overlaying layers.
• Identifying what is nearby (proximity).
• Quantifying the results (statistics).

5
Extract toolset

• Clip
• Select
• Split
• Table select

6
Clip

• Reduce the spatial extent of one layer based on
  the extent of another.

7
Split

• Breaks the input features into multiple output
  feature classes.

8
Table Select

• Extracts selected attributes from an input table
  and stores them in a new output table.

9
Overlay Toolset

• Erase
• Identity
• Intersect
• Symmetrical difference
• Union
• Update

10
Erase

• Creates a feature class by overlaying the input
  features with the erase features.

11
Identity

• Geometric intersection of the input and identity
  feature classes.

12
Aggregating Features (intersect)

• Find those features falling within the spatial
  extent common to two layers.

13
Intersect

• Portion of features which are common to all
  inputs

14
Symmetric Difference

• Geometric intersection of the input and
  difference features.

15
Aggregating Features (union)

• Use Union to overlay two polygon layers.
• Has the combined attribute data of the polygons
  in the two inputs.
• Contains all the polygons from the inputs,
  whether or not they overlap.
• Produces a new layer combining the features and
  attributes of two polygon layers.

16
Union
17
Aggregating Features

• If aggregated features are saved as shapefiles
  the attribute data are not updated.
• If saved as feature classes in a geodatabase the
  attribute tables are updated in new fields called
  shape_area and shape_length.

18
Update

• Geometric intersection of the input features and
  update features

19
Proximity Toolset

• Buffer
• Multiple Ring Buffer
• Near
• Point Distance

20
Creating buffers around features.

• Finding what features are within a set distance.
• Finding what features are within a travel cost
  distance.
• Finding what features are within hearing range.

21
Buffer
22
Near
23
Point Distance

• Euclidean distance

24
Generalization Toolset

• Dissolve features of a single layer based on a
  specified attribute value.
• Takes out borders between features.

25
General Toolset

• Append
• Copy
• Delete
• Rename
• Select Name

26
Statistics Toolset

• Frequency
• Summary Statistics