GeoEFM has two calculators, one that performs single instance queries of spatial layers (Calculator) and one that performs repeating queries of spatial layers (Batch Calculator). In addition to the HSI features described earlier in this chapter, the Calculator can also be used to query raster value ranges (Figure 18). The Calculator also has several components related to feature classes, though those have not been rigorously tested and should be used with caution.
Figure 18. GeoEFM Calculator interface being used to apply a raster cell value range.
Cell Value is a simple query that applies a user-defined range to an input raster resulting in an output raster that contains only the cells and corresponding values that are within the range (Figure 19). Ecologically, this is typically used to filter areas that are not relevant to the EFM relationship being considered. In this sense, Cell Value is similar to the Apply HSI option, though Cell Value does not allow for partial suitability, areas are either in range or dropped from the output layer. Output names are limited to a maximum of 13 characters for raster operations, as required by ArcMap.
Figure 19. Spatial layers for Little minnow spawning. Top image shows a depth raster (blue) from a river hydraulics model. Bottom image show raster of depths from 0.0 to 3.0.
The Batch Calculator performs a user-defined spatial operation for multiple raster layers. This feature is most commonly used when processing layers for one EFM relationship and many flow regimes. In this case, the same spatial operations, whether Cell Value or Apply HSI, needs to be done for each of the implicated relationship-flow regime Standard Views. To use the Batch Calculator, layers to be processed must share a common tag as created in EFM and set via the Manage Standard View interface.
The Batch Calculator allows users to declare the relationship and tag (and, thereby, the corresponding layer set) to be processed, to specify an output prefix and location, and to define the spatial operation (Figure 20). Clicking the Process button executes the operations. Output rasters are shown in their Standard Views and associated in accordance with Auto-List settings. Output name length can be challenging for layers generated by the Batch Calculator. The default name is “prefix_InputRasterName”. Prefix is allowed a maximum of 2 characters and then “InputRasterName” is truncated as necessary to stay within the 13-character ArcMap limit.