Once upon a time, there …

Some Key PointsSome Key Points

•Structure needs to be defined by objective, proper scale, and variable of interests;

•All structural elements are dynamic (i.e., constantly changing over time);

Quantifying Landscape Structure:Quantifying Landscape Structure:- from realty to abstract -

Illustration

patch

road

Reality

Abstract

C

P P

s

ij ijj

s

i

s

1

211

ln

ln

Spatial Patterns:

Points

Continuous

Lattice/Polygons

Geographical Information System (GIS): an organized collection of hardware, geographical data, and persons that is designed to effectively capture, store, update, manipulate, analyze, and display all forms of geographically referenced information. GIS packages are rater- or vector-based. Popular ones include ESRI’s products (ARC/INFO, ARCVIEW, ARC/GIS) and ERDAS’ products (Imagine).

Patchinterior

AMPIAEI

AMEI

Roadsides

A Land Mosaic

LandscapeLocation: Lat. Long., elev., ecoregion, climate zone,

origin and disturbance history, etc.

Total area (ha, acre)

PatchType and number Density (Number of patches per unit area) Size (ha): mean, skew ness, variation, min, & maxFrequency table (i.e., size class distribution)ShapeFractal dimension

Patchinterior

AMPIAEI

AMEI

Roadsides

1000 m

0

5

10

15

20

25

30

35

Pe

rce

nt

of To

tal A

rea

Cover Type

0.39% 0.02%

4.03%

18.93%

' 4.87%

31.31%

5.44%

12.76%

22.25%

Size class distribution (i.e., frequency table): percent of the total study area comprised by each land cover type

Landscape structure in the Border Lakes and Sylvania (Mladenoff et al. 1993.)

Study Landscapein N. Wisconsin

Landsat TM cover map & a subscene. The land mosaics with AEI are significantly different from the cover map (D-AEI Model)

Zheng & Chen (2000)

Patch Shape: Shape IndexPatch Shape: Shape Index

Fl

w 1) Where l is the length and

w is the width of the patch.

Dp

A

2 2) Where p is the perimeter of the patch, and A is the area of the patch.

Application of shape index in landscape analysis:

Landscape change over time

Among patch type

Among different parts of the landscape

Among landscapes

Exercise: calculate F & D of the following patches:

2

Patch shape: Fractal DimensionPatch shape: Fractal Dimension

DN

r

ln ( )

ln ( )

Where N is number of steps used to measure a pattern unit length, and r is the scale ratio.

A fractal will look the same whatever the level of resolution used to observe the object, i.e. a shape made of parts similar to the whole in some way. (Mandelrot 1985)

What is the fractal of (a), (b), ©, and (d)?