Feature Decimation
Decimation Factor
DTED files can be very large, and you may not always need all the data at the full resolution of the input DTED (if you are testing, for example). For this reason, you can enter a decimation factor that specifies how much of the file is skipped.
If you enter a factor of 1, you will get the entire file. If you enter a factor of 2, you will get every second point horizontally, and every second point vertically (thus significantly reducing the file size).
Dataset Parameters
Read as DEM Raster
DTED files can be interpreted by FME as a group of associated point features or as a single grid feature. These settings determine which way FME will handle the raster data. Raster files can be translated much more efficiently as grid features than as many point features.
If this option is selected, each raster file is handled as a single grid feature.
If this option is not selected, the elevation values in a raster file are handled as individual point features.
For example, accepting the default selection means that each raster file is handled as a single raster feature. Clearing the checkbox means that elevation values in a raster file will be handled as individual point features.
Feature Type Name(s)
This parameter allows you to choose different naming schemes, and the number of feature types generated for the reader.
Feature type name choices:
- From File Name(s): Generates one feature type per source filename.
- From Format Name: Produces only a single feature type containing the format name.
Schema Attributes
Additional Attributes to Expose
Use this parameter to expose Format Attributes in Workbench when you create a workspace:
- In a dynamic scenario, it means these attributes can be passed to the output dataset at runtime.
- In a non-dynamic scenario, you can use this parameter to expose additional attributes on multiple feature types.
Use Search Envelope
Using the minimum and maximum x and y parameters, define a bounding box that will be used to filter the input features. Only features that intersect with the bounding box are returned.
If all four coordinates of the search envelope are specified as 0, the search envelope will be disabled.
Clip to Search Envelope
When selected, this parameter removes any portions of imported features being read that are outside the Search Envelope.
The example below illustrates the results of the Search Envelope when Clip to Search Envelope is not selected (set to No) and when it is selected (set to Yes).
- No: Any features that cross the search envelope boundary will be read, including the portion that lies outside of the boundary.
- Yes: Any features that cross the search envelope boundary will be clipped at the boundary, and only the portion that lies inside the boundary will be read. The underlying function for the Clip to Search Envelope function is an intersection; however, when Clip to Search Envelope is selected, a clipping operation is also performed in addition to the intersection.
