The “Reclassify” tool has the capability to modify the values of a raster by replacing existing information with new values. This is applicable to any variable stored in raster format, such as slope, elevation, precipitation, temperature, among others.
To conduct this practice, the previously created slope map is used along with the classification proposed by the FAO (2009), which involves regrouping the values of the slope raster into classes. Table 6 provides eight different classes, each containing slope values expressed in percentage and decimal degrees.
Slope gradient classes.
The “Reclassify” tool can be opened using the following path:
Geoprocessing > Toolboxes > Spatial Analyst Tools > Reclass > Reclassify
Tool Configuration
To configure the “Reclassify” tool, the following parameters should be set:
- Input raster: Select the layer containing the slope raster.
- Reclass field: Choose the field containing the slope values, which by default is usually “VALUE”.
- Reclassification: Click the “Classify” button to open a classification window. By default, the method is set to “Natural Breaks (Jenks)”. Choose the preferred classification method and define the number of classes (in this case, 8). Then, select the manual method to enter each class’s boundaries according to Table 6.
- Raster output: Select a directory or geodatabase to store the reclassified slope raster file.
Configuration of the “Reclassify” tool parameters.
Result
Executing the tool will generate a new raster containing the reclassified values based on the specified class boundaries. This new raster can then be used to create thematic maps that represent the spatial distribution of the slope classes across the area of interest.
Slope raster in degrees reclassified into eight categories.
