GSMNP:Notebook/Maxent/Creating a Range Map
A desirable model output not included in the standard html output is a binary range map for the species. This map has only 2 categories, habitat and non-habitat. The delineation of habitat must be chosen by the user based on the binomial test results in the Analysis of omission and commission section (5.1). As an example, we chose a Balanced training omission, predicted area and threshold value threshold for the Hooded Warbler model. The logistic threshold was 0.139. Our task is to create a binary map from the original logistic projection map where values greater than 0.139 are true (1) and values less than 0.139 are false (0). The procedure follows:
- Import the output logistic ASCII grid into ArcMap.
ArcToolbox[math]\displaystyle{ \Rightarrow }[/math]Conversion Tools[math]\displaystyle{ \Rightarrow }[/math]To Raster[math]\displaystyle{ \Rightarrow }[/math]ASCII to Raster
- Input ASCII raster file: path to output folder/species name_ASCII.asc – Output raster: path to output folder/pred_species abbrev
- Output data type (optional): FLOAT
- Set Spatial Analyst Workspace to output folder Spatial Analyst[math]\displaystyle{ \Rightarrow }[/math]Options...[math]\displaystyle{ \Rightarrow }[/math]General
- Working Directory: path to output folder
- Compute the logical comparisons
- Spatial Analyst[math]\displaystyle{ \Rightarrow }[/math]Raster Calculator
- hab_species abbrev = pred_species abbrev > threshold
- OK
After following the above recipe, the resulting grid will be in Arc binary grid format and have a value of 1 for habitat pixels, 0 for non-habitat pixels, and NODATA for pixels not inside the analysis mask
