In addition to the generic FME feature attributes that FME Workbench adds to all features (see About Feature Type Attributes), this format also adds format-specific attributes (Format Attributes).
USGS DEM data can be represented in two different ways in FME: FME raster features, or FME point features. FME raster features are the preferred, faster way. The method of FME feature reading can be set using the AS_DEMRASTER reader directive. For FME raster feature reading, each USGS DEM file is represented by a single feature with a feature type of Elevation_raster. All data is stored on this feature including elevation data, record type A header information, and record type C statistical information if it exists.
For FME point feature reading, except for possibly the last feature, all features read from USGS DEM files are 3D points with feature types of Vertical. If record type C exists in a USGS DEM file, then the last feature will be a feature containing information found in record C. This feature will not have any geometry because record C does not represent any type of geometry. Record C contains statistics about the accuracy of the data in the USGS DEM file.
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Attribute Name |
Contents |
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dem_type |
The USGS DEM geometric type of this entity. Range: dem_raster|dem_point|dem_record_C Default: No default |