Transcript Teaching with Technology

Spatial Data Analysis
The accurate description of data related to a process
operating in space, the exploration of patterns and
relationships in such data, and the search for
explanation of such patterns and relationships
Spatial Analysis vs. Spatial Data Analysis
Spatial Analysis = what is here, and where are all the X’s ???
Spatial Data Analysis = observation data for a process operating in
space and methods are used to describe or explain the behavior, and/or
relationship with other phenomena.
Types of Metics
Area Metrics
Patch Density, Size and Variability
Edge Metrics
Shape Metrics
Core Area Metrics
Nearest-Neighbor Metrics
Diversity Metrics
Contagion and Interspersion Metrics
Landscape Ecology
Structure = the spatial relationships among the
distinctive ecosystems or “elements”
Function = the interactions among the spatial
elements
Change = the alteration in the structure and
function of the ecological mosaic over time
Fragstats:
McGarigal, K. and Marks, B.J. 1995, Fragstats: Spatial
Pattern Analysis Program for Quantifying Landscape
Structure. General Technical Report, PNW-GTR-351.
Portland, OR, U.S. Department of Agriculture, Forest
Service, Pacific Northwest Research Station, 122p.
Terms
Landscape = a “mosaic” of patches.
Patch = the basic “element” or “unit” of the landscape defined
relative to the phenomenon, that are dynamic and occur at
multiple ecological scales with unique and meaningful
boundaries
Matrix = the most extensive and most connected element
dominating the function of the landscape
Class = a category or type of patch
Ecological Scale = both the “Extent” (area within the landscape
boundary) and “Grain” (the size of the units of observation)
defining the dynamics of the phenomenon.
Landscape Structure
Physiognomy / Pattern
Composition = The presence and amount of each
element type without spatially explicit measures.
Proportion, richness, evenness, diversity
Configuration = The physical distribution in space and
spatial character of elements.
Isolation, placement, adjacency
** some metrics do both **
Area Metrics
Absolute Metrics
Total Area (TA)
Class Area (CA)
Relative Metrics
Percent
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(%extent), or %land = percent of total occupied by each class
(LSIM) = Landscape similarity Index:
• For each element LSIM = %extent
Largest (LPI), Smallest (SPI)
Density, Size and Variability
Number of element (NE) or Patches (NP)
Density of Element - patch density (PD) = number of
elements on a per unit basis
Mean Element or Patch size (MPS)
for the landscape
for the class
Patch size coefficient of variation (PSCV) = a measure
of relative variation, the difference in patch size among
patches, (I.e. variability as a percentage of the mean).
Edge Metrics
Total Edge (TE) and Edge Density (ED), for all
classes and by class
Perimeter (PERIM) by patch
Edge Contrast Index (EDGECON) = difference
across a boundary
total edge contrast
mean edge contrast
area-weighted mean edge contrast
contrast-weighted edge density
Shape Metrics
perimeter-area relationships
Shape Index (SHAPE) -- complexity of patch compared
to standard shape
vector uses circular; raster uses square
Mean Shape Index (MSI) = perimeter-to-area ratio
Area-Weighted Mean Shape Index (AWMSI)
Landscape Shape Index (LSI)
Fractal Dimension (D), or (FRACT)
log P = 1/2D*log A; P = perimeter, A = area
P = sq.rt. A raised to D, and D = 1 (a line)
as polygons move to complexity P = A, and D -> 2
A few fractal metrics
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Double log fractal dimension (DLFD)
Mean patch fractal (MPFD)
Area-weighted mean patch fractal dimension (AWMPFD)
Core Area Metrics
The area within a patch beyond a buffer or
“edge” distance
Corresponding metrics with those dealing with
Density
Size
Variability
Nearest-Neighbor Metrics
The distance from a patch to the nearest
neighboring patch of the SAME type
Nearest-neighbor distance (near) = just distance
Proximity index (PROXIM), using a search
radius – distinguishes sparse distribution from
complex clusters
Diversity Metrics
Influenced by the compositional and structural
components of diversity:
Richness = the number present
Evenness = the distribution of area among different types
Shannon’s Diversity Index (SHDI): magnitude not
meaningful, a relative index
Simpson’s diversity Index (SIDI): the probability that any
types selected would be different – (also a modified version)
More on Diversity
Patch Richness (PR) and Patch Richness
Density (PRD)
Evenness – or, the distribution of area among
types
The compliment is Dominance
Evenness = 1- dominance
Shannon’s evenness index (SHEI)
Simpson’s Evenness Index (SIEI)
Contagion, Interspersion and Juxtaposition
When first proposed (O’Neill 1988) proved incorrect, Li &
Reynolds (1993) alternative
Based upon the product of two (2) probabilities
Randomly chosen cell belongs to patch “i”
Conditional probability of given type “i” neighboring cells
belongs to “j”
Interspersion (the intermixing of units of different patch
types) and Juxtaposition (the mix of different types
being adjacent) index (IJI)