Here are described step-by-step how to conduct a complete analysis, beginning with environmental data and ending with a validated Habitat Suitability map.


A.Preparing the maps

This section describes how to prepare your data so that they be used as ecogeographical variables (EGV) in Biomapper. This involves:
  1. Selecting relevant/available data
  2. Importing/converting them into a GIS application
  3. Deriving ecologically-relevant variables from them
  4. Converting them to Biomapper/Idrisi format
  5. Preparing the EGVs for ENFA
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B.Ecological Niche Factor Analysis (ENFA)

The ENFA summarises the many, redundant EGVs into uncorrelated niche factors. Studying these factors and other results will give you a better ecological understanding of the focal species.
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C.Habitat Suitability computation

Using only a few ENFA factors, you will now map the habitat suitability of your study area. The chosen algorithm will compute, for each cell, a value between 0 and 100, from unsuitable to optimal habitat.

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The predictive accuracy of this map can then be evaluated by a specific cross-validation procedure: the Boyce index.
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The final HS map can be improved, for instance by reclassifying or smoothing it.
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The steps B, C and D may be done sequentially in one shot by using the Automatic analysis dialog box (Menu Multivariate analyses/Automatic analysis…). Although it can speed up the operations and make them easier, you should first follow the operational processes “manually” a few times in order to better understand how things are interconnected. By the way, the first time you study a species, you should do it manually in order to keep an eye on each part of the whole process. Afterward, when you will be tuning the model, trying various approaches, the automatic analysis will prove a very practical functionality.