SUBDIV

SUBDIV - Subdivision Analysis

Development

SUBDIV was developed within the SPIN project (Contract No. EVG2-2000-0512, founded by the 5th Framework Program of the EU).

Objective / Purpose

ArcView 3.x entension with user friendly graphical user interface (GUI) and help documentation for calculation fragmentation metrics from Jaeger (1999).

Author / Principal Investigator

LARG, Stefan Lang

Platform specification

subdiv.avx has been tested under ArcView 3.2 and ArcView 3.3 in a Windows operating system 98/NT/2000/XP.

Development environment

Avenue Script

Background and brief description / Main functions

SUBDIV provides a selected set of subdivision metrics for basic ecological and structure-related quantifications of fragmentation. The group of subdivision metrics measures landscape dissection and fragmentation on the level of specified classes (Jaeger, 2000). Landscape dissection (e.g. by roads) does not lead to a significant loss of area, as the portion of land covered by the dissecting lineaments is comparatively small. But with an increasing number of dissected patches the squared area successively decreases compared to the original undissected area. Since the concept of the original area (reference area) is somewhat ambiguous, when patches have disappeared or were shrinking over time, the user can choose among four different ways of considering reference area (i.e. landscape, class, user-defined, graphic-based).

To characterise the degree of fragmentation the following metrics are calculated: Landscape SUBDIVI-SION is based on the degree of COHERENCE and measures the probability that two randomly set points do not belong to the same undissected area. The SPLITTING INDEX is the number of equal sized areas at a given division. The EFFECTIVE MESH SIZE is the average size of those areas.

The SUBDIV extension is programmed in AVENUE (ArcView 3.x environment) and supports the usage of polygon data. Results are written into a dbf table in the respective home directory.

Source Code

Not available.

Status

The current version 1.0 is in an evaluation status until the SPIN project end 04/2004.

Pricing

SUBDIV is free of charge under its attached license agreement.

Download

The latest version 1.0 you can download here: subdiv.zip

Literature

Lang, S., U. Walz, H. Klug, T. Blaschke & R.U. Syrbe (2008): Landscape metrics – A toolbox for assessing past, present and future landscape structures. In: Vassilopoulos, A. et al (eds.): Geoinformation Technologies for Geocultural Landscapes: European Perspectives. CRC Press/Balkema (Taylor & Francis Group). Leiden, The Netherlands, pp. 207-234.

Lang, S. & T. Blaschke (2007): Landschaftsanalyse mit GIS, UTB-Reihe. - Ulmer Verlag, Stuttgart, 420 pages.

For further information please contact:

Stefan Lang

email: stefan.lang@sbg.ac.at

webpage last checked

13/04/2012

© LARG (Landscape And Ressource Management Research Group), Z_GIS