生成一个阴影救济效果,对visua有用lizing terrain.
Each selected input band will be converted to a GRAY8 band with hillshade values between 0 and 255. Additionally, if Interpolate Nodata is set to No or if the band has a nodata value, an additional ALPHA8 band will be generated, with a value of 0 where the input was nodata and a value of 255 where the input was data.
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.
Parameters
Azimuth
Azimuth angle of the light source, expressed in positive degrees from 0 to 360, measured clockwise from north. The default value, 315, is generally used to generate shaded maps.
Altitude
Altitude angle of the light source above the horizon, expressed in positive degrees, with 0 degrees at the horizon and 90 degrees directly overhead.
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 that is set to the nodata value (that is, the alpha band value will be set to 0). Additionally, when any pixel in the 3x3 window used to calculate the hillshade value is equal to nodata, the output pixel will also be set to nodata.
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 slope and aspect. 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. TheRasterSelectorcan 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, seeTransformer Parameter Menu Options.
Transformer Categories
FME Licensing Level
FME Professional edition and above
Technical History
Associated FME function or factory: @Hillshade
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