Vector Data

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Vector Data

• Shapefiles
• Points
• Lines
• Polygons

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Raster Data

• Grids, Images, DOQ (digital orthophoto quad),
  scanned files, etc.

(Chesterfield, SC)
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Vector Data Analysis

• Buffering

• Points, lines, or polygons
• Different buffer distances
• Multiple bands
• Overlapped or dissolved zones

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Vector Data Analysis

• Map Overlay

Point-in-Polygon
Union
Polygon Overlay
Intersect
Line-in-Polygon
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Combining Attributes After Overlay

• Enumeration Rule
• each attribute preserved in output
• Dominance Rule
• one value wins
• Contributory Rule
• each attribute value contributes
  to result

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Vector Data Analysis

• Map Coverage Manipulation ArcView

dissolve
merge
clip
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Map Coverage Manipulation

• Dissolve
• Removes boundaries between polygons that have the
  same value of a selected attribute.

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Map Coverage Manipulation

• Clip
• Includes only those features of the input theme
  that are within the areal extent of the clip
  theme.

clip theme (Upper Salmon River Watershed)
input theme (Idaho counties)
result (watershed divided into counties)
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Map Coverage Manipulation

• Merge
• Creates a new theme by piecing together two or
  more themes however, the boundaries between the
  themes remain intact.

Single theme
Separate themes
Snake River Plain Aquifer
Idaho counties
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Vector Data Analysis

• Map Coverage Manipulation ArcInfo

erase
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Vector Data Analysis

• Map Coverage Manipulation ArcInfo

split
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Vector Data Analysis

• Map Coverage Manipulation ArcInfo

update
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Vector Data Analysis

• Map Coverage Manipulation ArcInfo

eliminate
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Proximity Analysis

• Distance Measurement ArcView
• Assign data by location

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Vector Data Analysis

• Distance Measurement ArcInfo

Near
Pointdistance
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Raster Data AnalysisMap Algebra

• Local Operation

Single grid
Multiple grid (addition)
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Raster Data Analysis Map Algebra

• Neighborhood Operation

(Rectangular, 3x3)
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Raster Data Analysis Map Algebra

• Zonal Operation

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Raster Data Analysis Map Algebra

• Distance Measurement or Global Operation
• Physical Distance

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Map Algebra Global Functions Based on Euclidean
Distance
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Map Algebra Euclidean Allocation and Direction
Functions
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Map Algebra Raster Data Analysis

• Distance Measurement or Global Operation
• Cost Distance

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Single Raster Analysis Tools
Modules aiming at data exploration within a
single image that go beyond plain visualizations.
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Map Overlay
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Comparing images
Differencing Question given are two images
showing the monthly mean temperatures (C) for
Australia in January and in February. What
changes did occur?
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Crosstabulation
Imagine two maps (raster images) which tell us
about the landusage of a certain district for two
consecutive years. As a basis for future planings
we need to learn about the changes that occured
in that district. Did forests change? Did they
grow or has their area decreased? What classes do
we meet this year where urban areas have been the
last year? etc.
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Image Calculator - a multitalent
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What's the minimum of the seven input images
(IMAGE1 to IMAGE7)? OUTPUT MIN(IMAGE1,
MIN(IMAGE2, MIN(IMAGE3, MIN(IMAGE4,
MIN(IMAGE5, MIN(IMAGE6, IMAGE7)))))) Notice
the nesting of the MIN function - computation
starts from the innermost MIN pair. If you use
trigonometric functions, angle values have to be
converted to radians. This too can be easier by
nesting the commands needed OUTPUT
RAD(COS(IMAGE1))RAD(SIN(IMAGE2)) Simple
computations would take quite a long time doing
it with the functions. 7 calls to OVERLAY and 9
to SCALAR would be necessary in the following
case OUTPUT (((IMAGE11.34-IMAGE23.45) /
(IMAGE15.34IMAGE27.21))
((IMAGE31.24-IMAGE46.5) /
(IMAGE38.7IMAGE42.5))) 25.13 Pay
attention to the parentheses, they determine the
sequence of the calculations. As you realize,
some functions accept the mixing of numbers and
images as input. If you really like, you may only
use numbers with several of the functions, which
turns the Image calculator into a normal
calculator SQR(4)SQR(4) returns? Exactly
32.00000
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Logical Expresions
We are interested not only in the areas equal to
or above 800 meters but also those below 1000
meters OUTPUT (GAISBERGgt800) AND
(GAISBERGlt1000) Assign all pixels a value of 1
where IMAGE1 is greater than IMAGE2 OUTPUT
IMAGE1 gt IMAGE2 Perform more complex
queries OUTPUT (IMAGE1gtIMAGE2) AND
(IMAGE3gt100) OR (IMAGE2 gt IMAGE3) NOT
(IMAGE1 lt 150)