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Patch Analyst

What it is
How it works
What it does
Indices in Patch Analyst
Versions

What it is

Patch Analyst is a tool for quantifying landscape structure that can be downloaded off the Internet from http://flash.lakeheadu.ca/~rrempel/patch/

Patch Analyst is a modified version of FRAGSTATS which has been developed to work specifically within ArcView GIS. It consists of a series of programs written in Avenue and C.

Patch Analyst can work on vector (shape) or raster (grid) data structures (themes within ArcView). The spatial statistics within Patch Analyst are applied to the two classified videography images, which can be put into ArcView as themes in grid (raster) format.

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How it works

Once Patch Analyst has been added as an ArcView extension, it is activated by clicking on 'Patch' in the ArcView menus and selecting the 'Spatial Statistics' option. The result of selecting the 'Spatial Statistics' option is that a dialogue box is opened that contains statistics inputs and selections. This allows the user to select the theme upon which they want the statistics to operate and also the type of statistics.

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What it does

Patch Analyst allows the data to be analysed within three levels of hierarchy.

• Landscape relates to all the patches, polygons, contiguous cells or shapes in a view or theme.
  
  
• Classes relate to all the patches, polygons, contiguous cells or shapes in a theme, view or landscape that have the same value for a given attribute.
  
  
• Patches relate to the individual polygons or contiguous set of cells or shapes. Each patch has a separate record or row in the theme attribute table.
  

(Elkie et al., 1999)

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Indices in Patch Analyst

Indices that can be calculated in Patch Analyst include:

Area Metrics

• Class area
  
  
• Landscape area
  

Patch density and size metrics

• Number of patches
  
  
• Mean patch size
  
  
• Median patch size
  
  
• Patch size standard deviation
  
  
• Patch size coefficient of variance
  

Edge metrics

• Total edge
  
  
• Edge density
  
  
• Mean patch edge
  
  
• Contrasted weighted edge
  

Shape metrics

• Mean perimeter-area ratio
  
  
• Mean shape index
  
  
• Area weighted mean shape index
  
  
• Mean patch fractal dimension
  
  
• Area weighted mean patch fractal dimension
  

Look up the glossary for more information on these indices

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Versions

There are two versions of Patch Analyst:

• a vector only version
  
  
• a vector and raster version
  

The vector and raster version requires ArcViews spatial analyst extension. These programs have been written to make landscape indices an extension to ArcView's spatial analyst functionality. Patch analyst has been developed by the Sustainable Forest Management Network (NCE) and the Centre for Northern Forest Ecosystem Research (OMNR) in the USA (Elkie et al., 1999).

Do this - Using Patch Analyst - Why?
Read the Kidman Springs case study. Do you think that the patch statistics applied using Patch Analyst and ArcView give a useful description of patterning in this landscape? How effective would the description be without it?

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