Analyzing Spatial Relationships

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Analyzing Spatial Relationships

• Engineering Applications of GIS
• Civil and Environmental Engineering
• CEEn 514

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Spatial Relationships

• Where features are located in relation to other
  features
• Nearby
• Adjacent
• Inside
• Intersection
• Topology is the Key!

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Selecting Features of One Theme with Another

• Select by Theme
• Are within a distance of
• Intersect
• Are completely within
• Completely contain
• Have their center in
• Contain the center of

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Finding Nearby Features

• Points to Lines
• Points to other Points
• Are within a distance of
• Can create new selections, add to current
  selections or select from current selections
• Unsure how polygons work with this option

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Finding Adjacent Features

• Polygons adjacent to selected polygons
• Are within a distance of value should be 0.
• Can create new selections, add to current
  selections or select from current selections
• This may work for polygons adjacent to lines
  try it!

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Finding Features Within

• Finding Points or Polygons that are Within
  Polygons
• Are completely within
• Completely contain
• Have their center in
• Contain the center of

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Finding Intersecting Features

• Lines that intersect lines or polygons
• Polygons that intersect polygons

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Spatial Joins

• Appends the fields of one theme table to those of
  another theme table
• Polygons attributes to points
• Inside spatial join
• Point attributes to points
• Nearest spatial join

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Buffers

• Creates a graphic or features a specified
  distance from the features of the input theme
• Always results in a new polygon theme
• Can have selected features first

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Buffers

• You can buffer
• Points
• Lines
• Polygons
• Graphics
• May be from a selected set of features

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Buffer Options

• Specified distance
• Distance defined from an attribute field
• Potentially different for each feature
• Concentric rings
• Number of rings and distance between rings defined

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Buffer Options

• Create graphics
• Add to an existing theme
• Create a new theme
• You can also specify whether or not to dissolve
  overlapping boundaries

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Buffers (Rivers)
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Multiple Ring Buffers
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GeoProcessing Wizard

• Most important Tool for Spatial Analysis
• Dissolve features of a layer
• Merge features from two layers
• Clip features from a layer
• Intersect/Union two layers

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Dissolve
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Merge
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Clip
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Union/Intersect