Calculates the slope (maximum rate of change in z) for each cell of a raster.
Each selected input band will be converted to a Real64 band whose output value represents the slope.
Note that the horizontal and vertical units are expected to be equal. If this is not the case, the Scaler may be used prior to this transformer to apply an appropriate scale factor.
Input Ports
Input
Input features must contain raster geometries only.
Output Ports
Output
Raster features with the calculated slope values will be output through this port.
Parameters
Output Measurement
The measurement units of the output slope data.
When set to Degrees, the slope will be calculated in degrees. Values will range from 0 to 90.
When set to Percent Rise, the slope will be calculated as percent rise. Values will range from 0 to infinity. A flat surface will have a slope of 0 percent, a 45 degree surface will have a slope of 100 percent, and as the surface becomes more vertical the slope gets progressively larger.
Interpolate Nodata
Whether to calculate values at raster edges and near nodata values.
When this is set to No, there will be a one pixel border around the edge of the raster set to the nodata value. Additionally, when any pixel in the 3x3 window used to calculate the slope value is equal to nodata, the output pixel will also be set to nodata. If the input band does not have a nodata value, the output band nodata value will be set to -1.
When this is set to Yes, values around the edge and near nodata values will be estimated by interpolating missing values. Note that holes will not be filled in. That is, cells that are nodata in the input image will remain nodata in the output.
Algorithm
The algorithm used to calculate the slope. Some analyses have suggested that Horn's formula is better suited to rougher terrain, whereas Zevenbergen & Thorne's formula is better for smooth terrain.
Usage Notes
This transformer supports raster band selection. The RasterSelector can be used to modify this selection.
Editing Transformer Parameters
Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click 
beside the applicable parameter. For more information, see Transformer Parameter Menu Options.
Transformer Categories
FME Licensing Level
FME Professional edition and above
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