Extending ArcView’s
Spatial Analysis Capabilities
Phil Hurvitz
College of Forest Resources
University of Washington
April 7, 2003
Extending ArcView’s Spatial Analysis Capabilities
Overview
• Historical context of ESRI GIS spatial analysis
tools
• Limitations of ArcInfo/AML
• Advantages of ArcView/Avenue
• Introducing 4 ArcView/Avenue based
extensions for spatial analysis
• Conclusion
© Phil Hurvitz
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Extending ArcView’s Spatial Analysis Capabilities
Overview
• Historical context of ESRI GIS spatial analysis
tools
• Limitations of ArcInfo/AML
• Advantages of ArcView/Avenue
• Introducing 4 ArcView/Avenue based
extensions for spatial analysis
• Conclusion
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Extending ArcView’s Spatial Analysis Capabilities
Historical context of ESRI GIS spatial analysis tools
• ArcInfo has dominated the GIS market for
years (20+ years)
• New software tools have become available
more recently
• More functionality in a more user-friendly
environment
• ArcView (version 1.0, 1993?)
• ArcGIS (version 8.0, 1999?)
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Extending ArcView’s Spatial Analysis Capabilities
Historical context of ESRI GIS spatial analysis tools
ArcInfo interface
ArcView
interface
ArcGIS interface
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Extending ArcView’s Spatial Analysis Capabilities
Overview
• Historical context of ESRI GIS spatial analysis
tools
• Limitations of ArcInfo/AML
• Advantages of ArcView/Avenue
• Introducing 4 ArcView/Avenue based
extensions for spatial analysis
• Conclusion
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Extending ArcView’s Spatial Analysis Capabilities
Limitations of ArcInfo/AML
• ArcInfo is a very robust environment for
spatial analysis
• AML (Arc Macro Language) provides a
programming environment for automating
functionality
• AML is a procedural language-based (macro)
API for development of applications
• + As users become better at the command line,
their programming/command skills will increase
• – If users do not start programming, their
programming/procedure skills will never increase
beyond a very basic level
• – Procedural languages are not compiled, so their
programs run slowly
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Extending ArcView’s Spatial Analysis Capabilities
Limitations of ArcInfo/AML (continued)
• – AML is “clunky”
• Basic dialogs do not exist
• File saving, file writing, feature/record selections, graphical symbol
definition
• File locations are difficult to handle
• Hard-coded pathnames are easier to program
• Hard-coded pathnames reduce flexibility
• – AMLs are completely file-based
• AMLs exist as separate files that must be managed
• Files can get corrupted, incorrectly altered, or lost without
proper management
• Inter-application macros must refer to specific AML
files/pathnames
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Extending ArcView’s Spatial Analysis Capabilities
Limitations of ArcInfo/AML (continued)
• – Because ArcInfo has no GUI, associating
scripts with buttons or menus requires
ArcTools programming
• – ArcTools provides an API for creating GUIs
• The ArcTools API is very difficult to code
• ArcTools still runs on an AML back-end, which is
slow
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Extending ArcView’s Spatial Analysis Capabilities
Overview
• Historical context of ESRI GIS spatial analysis
tools
• Limitations of ArcInfo/AML
• Advantages of ArcView/Avenue
• Introducing 4 ArcView/Avenue based
extensions for spatial analysis
• Conclusion
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Extending ArcView’s Spatial Analysis Capabilities
Advantages of ArcView/Avenue
• ArcView provides a new API: Avenue
programming language with several major
advantages (and a few drawbacks)
• – ArcView runs in native mode with no command
line
• API needs to be learned as an entire new environment
• + Avenue is compiled code rather than procedural
• Runs much faster
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Extending ArcView’s Spatial Analysis Capabilities
Advantages of ArcView/Avenue, continued
• + Scripts can be easily associated with menus,
buttons, and tools in the GUI
• + Not file-based
• Scripts are typically created & stored in projects
rather than as stand-alone files
• Scripts can be packaged in “Extensions,” which
provide complete application functionality as
simple add-ins
• Extension is a single OS file containing all
necessary scripts & GUI controls
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Extending ArcView’s Spatial Analysis Capabilities
Overview
• Historical context of ESRI GIS spatial analysis
tools
• Limitations of ArcInfo/AML
• Advantages of ArcView/Avenue
• Introducing 4 ArcView/Avenue based
extensions for spatial analysis
• Conclusion
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Extending ArcView’s Spatial Analysis Capabilities
Introducing 4 ArcView/Avenue based extensions for spatial analysis
•
•
•
•
© Phil Hurvitz
LineSlope Analyst
LMS Analyst
FocalPatch Analyst
WBC Analyst
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Extending ArcView’s Spatial Analysis Capabilities
Introducing 4 ArcView/Avenue based extensions for spatial analysis
•
•
•
•
© Phil Hurvitz
LineSlope Analyst
LMS Analyst
FocalPatch Analyst
WBC Analyst
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Extending ArcView’s Spatial Analysis Capabilities
LineSlope Analyst
200 ft
205 ft
• Stream or road gradient is an important metric
in hydrology & forest engineering
• Gradient is easily calculated on a segment-bysegment or line-by-line basis
slope % = rise / run * 100%
(205 – 200) / 30 * 100% = 16.7%
30 ft
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Extending ArcView’s Spatial Analysis Capabilities
LineSlope Analyst
• Although gradient is easily calculated on a segmentby-segment or stream-by-stream basis, it takes
programming to calculate gradient for an entire
stream data set.
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Extending ArcView’s Spatial Analysis Capabilities
LineSlope Analyst
• LineSlope Analyst Extension adds a single button to
calculate gradient for any linear feature
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Extending ArcView’s Spatial Analysis Capabilities
LineSlope Analyst
© Phil Hurvitz
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Extending ArcView’s Spatial Analysis Capabilities
Introducing 4 ArcView/Avenue based extensions for spatial analysis
•
•
•
•
© Phil Hurvitz
LineSlope Analyst
LMS Analyst
FocalPatch Analyst
WBC Analyst
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Extending ArcView’s Spatial Analysis Capabilities
LMS Analyst
• The Landscape Management System (LMS) is
an integrated forest growth model,
visualization, and analysis application
• Incorporates GIS data in several modules
• EnVision or SVS visualization module
• Tree list expansion factors (rely on stand area)
• Growth models (require stand-level topographic
characteristics)
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Extending ArcView’s Spatial Analysis Capabilities
LMS Analyst
• Stand topographic metrics are needed for
growth models
•
•
•
•
© Phil Hurvitz
Mean elevation per stand
Mean slope per stand
Mean aspect per stand
USGS or LiDAR based DEMs can be used to
calculate these metrics
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Extending ArcView’s Spatial Analysis Capabilities
LMS Analyst
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Extending ArcView’s Spatial Analysis Capabilities
LMS Analyst: Mean Elevation
• Mean elevation is a simple calculation
 n

E   E / n
 i 1 
E  1146 ft
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Extending ArcView’s Spatial Analysis Capabilities
LMS Analyst: Mean Slope
• Mean slope is a simple calculation
 n

S   S / n
 i 1 
S  20 %
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Extending ArcView’s Spatial Analysis Capabilities
LMS Analyst: Mean Aspect
• Mean aspect is not a simple calculation
• 359º = nearly due north
• 1º = nearly due north
• ( 359º + 1º ) / 2 = 180º
• Nearly due south!
359º
1º
180 º
• Must convert values to radian measures and
use a more complicated calculation
• Algebraic & trigonometric functions are
available in ArcView
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Extending ArcView’s Spatial Analysis Capabilities
LMS Analyst: Mean Aspect
• Mean aspect is not is a simple calculation
 n

A    f ( A)  / n
 i 1

custom calculation
A  220
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Extending ArcView’s Spatial Analysis Capabilities
LMS Analyst: Multiple nested buffers
• Forests & Fish rules require multiple nested
riparian buffers
• ArcView includes a simple buffer method
• Single buffers
• Nested buffers, but only at equal-width
• Nested buffers required by F&F are not equalwidth
• LMS Analyst MultiBuffer creates multiple
nested buffers at users’ definition
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Extending ArcView’s Spatial Analysis Capabilities
LMS Analyst: Multiple nested buffers
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Extending ArcView’s Spatial Analysis Capabilities
Introducing 4 ArcView/Avenue based extensions for spatial analysis
•
•
•
•
© Phil Hurvitz
LineSlope Analyst
LMS Analyst
FocalPatch Analyst
WBC Analyst
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Extending ArcView’s Spatial Analysis Capabilities
FocalPatch Analyst
• FRAGSTATS is commonly used to calculate
spatial metrics for landscapes, patches, or
classes
• FRAGSTATS as originally written calculates
metrics only for the entire landscape or for
entire or specific patches
• What are the landscape characteristics in a
neighborhood around a specific location?
• How do neighborhood landscape
characteristics change across large landscapes?
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Extending ArcView’s Spatial Analysis Capabilities
Fragstats
• Patch metrics
© Phil Hurvitz
(image from Fragstats manual)
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Extending ArcView’s Spatial Analysis Capabilities
Fragstats
• Class metrics
© Phil Hurvitz
(image from Fragstats manual)
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Extending ArcView’s Spatial Analysis Capabilities
Fragstats
• Landscape metrics
© Phil Hurvitz
(image from Fragstats manual)
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Extending ArcView’s Spatial Analysis Capabilities
Focal Functions in GIS
• Processing occurs on a central cell in
conjunction with the values associated in its
neighborhood
• “Moving window”
• “Kernel”
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Extending ArcView’s Spatial Analysis Capabilities
FocalPatch Analyst
• On a cell-by-cell basis
• Creates a point feature at the cell center
• Extracts the region in a user-specified radius
around the point
• Calculates landscape metrics for that circle
• Places metrics back into point attribute table
• Point data can be interpolated to create
different surfaces of each different focal
landscape metric
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Extending ArcView’s Spatial Analysis Capabilities
FocalPatch Analyst
• Extracts circular region from land cover
grid at user-defined radius
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Extending ArcView’s Spatial Analysis Capabilities
FocalPatch Analyst
• Calculates landscape metrics
Rempel’s interface
© Phil Hurvitz
Rempel’s batch script
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Extending ArcView’s Spatial Analysis Capabilities
FocalPatch Analyst
• Calculates
landscape metrics
• Values represent the
landscape metrics
for the circular focal
region around the
central cell
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Extending ArcView’s Spatial Analysis Capabilities
Patch Metrics and Utilization Distributions
• Some animal species respond to large
regions of landscapes
• Typical animal-landscape relationships are
analyzed either by point processes or by
land cover types
• Is there a relationship between local (focal)
landscape metrics and actual animal usage
of landscape?
• To which landscape characteristics do
animals respond?
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Extending ArcView’s Spatial Analysis Capabilities
Patch Metrics and Utilization Distributions
utilization distribution
(UD)
limit processing
to UD
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Extending ArcView’s Spatial Analysis Capabilities
Patch Metrics and Utilization Distributions
utilization distribution
© Phil Hurvitz
contrast-weighted edge surface
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Extending ArcView’s Spatial Analysis Capabilities
Patch Metrics and Utilization Distributions
• Regression techniques are used to determine
strength of relationship between utilization and
landscape metrics
• Multiple regression
• Raster regression within GRID
• Process described in paper submitted to
Ecology (Marzluff et al., 2003)
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Extending ArcView’s Spatial Analysis Capabilities
Introducing 4 ArcView/Avenue based extensions for spatial analysis
•
•
•
•
© Phil Hurvitz
LineSlope Analyst
LMS Analyst
FocalPatch Analyst
WBC Analyst
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Extending ArcView’s Spatial Analysis Capabilities
WBC Analyst
• Do patterns of urban environmental structure have an
effect on exercise?
• Are particular urban settings more conducive to
exercise?
• “Walk Friendly”
• “Bike Friendly”
• Urban structure must be quantified before answering
these questions
• GIS provides the tools for quantifying the
composition and configuration of urban structure
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Extending ArcView’s Spatial Analysis Capabilities
WBC Analyst
• Performs tasks that would be either impossible
or extremely time-consuming manually
• Analysis based on proximity to selected
households
• Based on Euclidean and network buffers,
network connectivity
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Extending ArcView’s Spatial Analysis Capabilities
WBC Analyst
• Tallies land uses within user-specified distance of
households
• Finds closest of each land use type, by Euclidean and
network distance
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Extending ArcView’s Spatial Analysis Capabilities
WBC Analyst
• Creates convex hull “neighborhood clusters”
of key urban land uses (e.g., grocery & retail
stores)
• Clusters are defined by particular land uses
and numbers of parcels within a specific
proximity
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Extending ArcView’s Spatial Analysis Capabilities
WBC Analyst
• Tallies land uses within
neighborhood clusters
• Determines Euclidean
and network distances to
each household’s closest
neighborhood cluster
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Extending ArcView’s Spatial Analysis Capabilities
WBC Analyst
• Telephone survey has obtained personal exercise
habits for 750 households in King Co.
• WBC Analyst creates output tables to be used for
statistical analysis with telephone survey results
• If there is a relationship between urban structure
and habits, it will be possible to predict the
“walkability” and “bikeability” of neighborhoods
based solely on readily available GIS data.
• CDC funding for initial project
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Extending ArcView’s Spatial Analysis Capabilities
Overview
• Historical context of ESRI GIS spatial analysis
tools
• Limitations of ArcInfo/AML
• Advantages of ArcView/Avenue
• Introducing 4 ArcView/Avenue based
extensions for spatial analysis
• Conclusion
© Phil Hurvitz
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Extending ArcView’s Spatial Analysis Capabilities
Conclusion
• New generation GIS environments coupled
with powerful and extensible APIs hold much
promise for creating science-based
applications
• ArcGIS, with its COM API will allow even
greater extensibility, allowing its object model
to work with any other COM-compliant
application (e.g. MS Office, next generation
LMS & EnVision)
• Extensions allow applications to be used
widely with little back-end configuration
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Extending ArcView’s Spatial Analysis Capabilities
Conclusion
• [email protected]
• http://gis.washington.edu/phurvitz
© Phil Hurvitz
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Extending ArcView’s Spatial Analysis Capabilities