Determine Weights Of Evidence Continuous Occurrences
Description
This container determines Weights of Evidence coefficients for selected spatial variables with respect to a map of occurrences, using the same Weights of Evidence method as Determine Weights Of Evidence Coefficients. Unlike that container, which works from a transition between an initial and a final map, this one works from a map where each cell holds a count of how many times some event occurred at that location, so the map of occurrences does not need to be binary.
This container accepts one or more Name Map hooks nested inside it, each assigning a name to a map. These named maps supply the values for the spatial variables referenced by Ranges.
Inputs
| Name | Type | Description |
|---|---|---|
| Occurrences | Map Type | Map of occurrences. Each cell holds the number of times the modeled event occurred at that location. |
| Mask | Map Type | Map defining, through cells other than its null value, which cells should be analyzed. Its cells must be representable as a 32 Bit Integer. |
| Ranges | Weights Type | Pre-defined ranges of each spatial variable for which the Weights of Evidence coefficients will be calculated. Only the ranges defined for the first transition are used; ranges defined for any other transition are ignored. |
Optional Inputs
| Name | Type | Description | Default Value |
|---|---|---|---|
| Fix Abnormal Weights | Boolean Value Type | If true, recalculates weights that would otherwise result in abnormal values, such as those arising from a division by zero. If false, those abnormal values are assumed to be zero. | No |
Outputs
| Name | Type | Description |
|---|---|---|
| Weights | Weights Type | Weights of Evidence coefficients obtained for the selected spatial variables, with respect to the given occurrences. |
Group
Notes
Cells with zero occurrences are also used in the calculation: one is always added to the number of occurrences found at a cell before it is used. Only cells located outside the area defined by Mask are excluded from the calculation.
Reports an error if a spatial variable named in Ranges is not provided by a nested Name Map hook.
Reports an error if Mask has cells that cannot be represented as a 32 Bit Integer.
This method was adapted from Agterberg & Bonham-Carter (1990), Goodacre et al. (1993), and Bonham-Carter (1994).
References
Agterberg, F.P. and Bonham-Carter, G.F., 1990: Deriving weights of evidence from geoscience contour maps for the prediction of discrete events. XXII Int. Symposium AP-COM, 381-395.
Bonham-Carter, G., 1994: Geographic information systems for geoscientists: modelling with GIS. Pergamon, 398 pp.
Goodacre, C. M., Bonham-Carter, G. F., Agterberg, F. P., Wright, D. F., 1993: A statistical analysis of spatial association of seismicity with drainage patterns and magnetic anomalies in western Quebec. Tectonophysics, 217, 205-305.
Internal Name
DetermineWeightsOfEvidenceContinuousOccurrences