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Methodology
1
Data
Preparation:
As
outlined in Discussion & Problems,
the original importation of ARCRaster
ASCII files for raster image creation
in IDRISI resulted in images of
slightly unequal dimensions at
same resolutions. As such, only
the USGS DEM raster image was
created in this manner, and its
properties were used to create
a blank base map in IDRISI. All
other data were downloaded in
ARCINFO format and converted to
shapefiles in ARCMap. These shapefiles
were imported using the IDRISI
Shape Editor function to create
vector layers which were then
converted to raster images.
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Criteria
Development & Standardization:
As
all criteria were not of equal
importance, a weighted linear
combination (WLC) multi-criteria
evaluation (MCE) was completed.
Before this could occur, both
continuous and discrete criteria
were standardized to a common
numeric range and constraints
identified. They could then be
combined by means of weighted
averages.
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The
methods of standardization varied
amongst criteria depending on
type and other important information.
The ASSIGN function was used to
standardize all discrete variables
(ie soil types), where values
of 0 - 255 were assigned to different
discrete classes based on pre-determined
relative suitability. Distances
from significant objects were
made a continuous variable by
means of the DISTANCE function.
Continuous variables were standardized
to the scale of 0 - 255 using
various mathmatical relationships
and pre-determined critical points
based on suitability information.
Please find below links to standardization
summary statistics tables for
both sites.
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