Spatial Data

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Spatial Data

• FE 423 - Lecture 1b

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OSB 111

• The Door
• your student card opens it
• dont open for others
• dont leave it open 20 seconds
• Machines
• at least two students per machine
• trade off on keyboard
• Logon spit
• users/spit/yourname

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Reading from ArcDoc

• Spatial modeling
• Cell-based Modeling with GRID
• Grid features and capabilities
• Basic concepts of grid-cell processing
• Getting started with GRID
• Getting data into GRID

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from Tuesday

• Make a spreadsheet that will estimate the peak
  flow Q5.157A.9Pa1.35F-.21 for a five year
  storm in Region XII, using a table of road
  crossings with their respective contributing area
  A, percent forest cover F, and annual rainfall
  Pa.
• - What does your spreadsheet look like?
• - How does changing F impact Q5?

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SCHEDULE
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OUTLINE

• OSB 111
• Spatial Data
• Data Types
• Attribute Tables
• Gridding the World
• ArcView
• opening data
• viewing data
• gridding data

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SPATIAL DATA points, arcs, polygons
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SPATIAL DATA

• Points

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SPATIAL DATA

• Points
• Arcs
• Polygons

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SPATIAL DATA

• Points
• Arcs
• Polygons
• Attribute Tables

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HYDROLOGYprocesses are intrinsically spatial
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POLYGON DATAhow we tend to represent data
vegetation(x,y)
y
topography(x,y)
x
soils(x,y)
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NON-SPATIAL HYDROLOGYwe model using a black box
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POLYGON HYDROLOGYRecognition of spatial
variability might lead to summing outputs from
black boxes
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POLYGON BLOCKSrepresenting spatial variability
with polygons produces a multitude of overlapping
polygons
Distance from stream
Aspect
Elevation
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POLYGON vs. GRIDreplace the myriad overlapping
polygons with a grid of identical square polygons
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GRID HYDROLOGYsumming point processes
P
ET
R
I
?S
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GRID BASICS - Thinking in GRID

• GRID-ing the World

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Gridding polygons, lines, points
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Gridding points, lines, polygons
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ASSIGNING VALUES
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A first view of ArcView

• Open Help first
• Project
• View
• Theme
• Element
• Extensions - Spatial Analyst
• Workspace - where work is saved
• Theme Table - attributes
• Legend Editor - right-click legend

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Converting to GRID

• Grid size
• specification
• matching
• Grid extent
• display
• existing grid
• Attributes
• specifying
• attaching

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Discussion Problems

• Grid the roads and stands using various grid
  sizes. Overlay and comment.
• Grid the stands, roads, and landslides to match
  the DEM grids. Verify they match.
• Overlay the road lines on the road grid. Comment.
  
• Repeat with polygons.

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Practice problem Grid the polygon coverage using
different methods and grid sizes
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majority
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centroid
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weighted