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 and FME point features.
FME Raster Features
FME raster features are the preferred, faster way. The method of FME feature reading can be set using the Read as DEM Raster reader parameter.
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.
FME Point Features
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.
|
Attribute Name |
Contents |
|---|---|
|
dem_type |
The USGS DEM geometric type of this entity. Range: dem_raster|dem_point|dem_record_C Default: No default |
Rasters
dem_type: dem_raster
USGS DEM raster features specify a matrix of x, y, and z coordinates. If known, the coordinate system will be specified.
|
Attribute Name |
Contents |
|
dem_file_name |
This is a string that specifies the basename of the raster file. |
|
dem_producer |
This is a string that specifies the producer of the data. |
|
dem_process_code |
This is a one-byte integer that specifies how to the data is processed. Range: 1...8 Default: 8 |
|
dem_sectional_indicator |
Unique to 30-minute DEMs, this 3-character string identifies 1:100,000-scale sections. |
|
dem_origin_code |
This is a 4-character string that specifies the mapping origin. |
|
dem_level_code |
This is an integer defining the DEM level. FME will not determine or check the validity of this assertion. Level 1: 7.5-minute or 30-minute DEM created by autocorrelaton or manual profiling from aerial photographs. Level 2: DEM created from digital line graph contours or equivalent, from any USGS map series up to 1:100,000 scale. Level 3: 7.5-minute DEM created from a digital line graph that has vertically integrated with all categores of hypsography, hydrography, ridge line, break line, drain files, and all vertical and horizontal control networks. Level 4: DEM created from electronic imaging sensor systems. Range: 1-4 Default: 1 |
|
dem_code_defining_elevation_pattern |
This specifies the regularity of the elevation pattern. Range: regular|random Default: regular |
|
dem_accuracy_code_for_ |
A number that specifies the existence of accuracy information for this dataset. 0 indicates unknown accuracy information. Range: 0|1 Default: 1 |
|
dem_spatial_ |
A positive real number used to specify a scale to apply to the elevation values in the z dimension. When specified for the writer, elevation values will be scaled appropriately. This value is tied with the value of dem_units; resolutions of 1 decimal place for feet and 2 decimals places for meters are permitted. Default: 1 |
|
dem_units |
The unit of measure for the z coordinate (the altitude). Range: meters|feet Default: No default |
|
dem_largest_primary_ |
Unique to level 2 DEMs, this integer specifies the largest primary contour interval if two or more primary intervals exist. If this field is not provided to the writer, it will be left blank. |
|
dem_largest_primary_ |
Unique to level 2 DEMs, this corresponds to the units of the largest primary contour interval. If this field is not provided to the writer, it will be left blank. Range: N.A.|meters|feet |
|
dem_smallest_primary_ |
Unique to level 2 DEMs, this integer specifies the smallest or only primary contour interval. If this field is not provided to the writer, it will be left blank. |
|
dem_smallest_primary_ |
Unique to level 2 DEMs, this corresponds to the units of the smallest primary contour interval. If this field is not provided to the writer, it will be left blank. Range: N.A.|meters|feet |
|
dem_data_source_date |
This specifies the year that the original compilation data was formed. If this field is not provided to the writer, it will be left blank. |
|
dem_data_inspection_and_revision_date |
This specifies the year of the date of completion or revision. If this field is not provided to the writer, the current year will be used. |
|
dem_inspection_flag |
This flag is blank if quality control has not been performed. Otherwise, it is flagged as “I” to indicate that all quality control processes are complete. If this field is not provided to the writer, it will be left blank. |
|
dem_data_validation_flag |
This single-digit integer specifies the type of data validation performed. Range: 0-5 Default: 0 |
|
dem_suspect_and_void_ |
This is a one-digit integer that indicates if the data contains void areas. If this field is not provided to the writer, it will be left blank. Range: 0-3 |
|
dem_data_edition |
This is a four-digit integer specifying the data edition or version used. Range: 0...9999 Default: 1 |
|
dem_percent_void |
This is an integer equal to the percentage of nodes in the file set to void (-32767). This is only populated if the dem_data_edition field indicates a void. If this field is not provided to the writer, it will be left blank. Range: 0...100 |
|
dem_edge_match_flag_WEST |
This integer flag specifies if edge-matching is required on the western edge of the raster. If this field is not provided to the writer, it will be left blank. Range: 1-4 |
|
dem_edge_match_flag_ |
This integer flag specifies if edge-matching is required on the northern edge of the raster. If this field is not provided to the writer, it will be left blank. Range: 1-4 |
|
dem_edge_match_flag_EAST |
This integer flag specifies if edge-matching is required on the eastern edge of the raster. If this field is not provided to the writer, it will be left blank. Range: 1-4 |
|
dem_edge_match_flag_ |
This integer flag specifies if edge-matching is required on the southern edge of the raster. If this field is not provided to the writer, it will be left blank. Range: 1-4 |
|
dem_vertical_datum_shift |
This number specifies the value to add to convert to NAVD88. If this field is not provided to the writer, it will be left blank. |
| file_datum_stats_avail |
The code indicating the availability of the statistics in attributes ‘file_datum_rmse_[x|y|z]’. 0 = unavailable, 1 = available Range: 0|1 Default: No default |
| file_datum_rmse_x |
RMSE of file’s datum relative to absolute datum (for the x-coordinate). Range: 0...999999 Default: No default |
|
file_datum_rmse_y |
RMSE of file’s datum relative to absolute datum (for the y-coordinate). Range: 0...999999 Default: No default |
| file_datum_rmse_z |
RMSE of file’s datum relative to absolute datum (for the z-coordinate). Range: 0...999999 Default: No default |
| file_datum_sample_size |
Sample size on which statistics for attributes ‘file_datum_rmse_[x|y|z]’ are based. Range: 0...999999 Default: No default |
| dem_datum_stats_avail |
The code indicating the availability of the statistics in attributes ‘dem_datum_rmse_[x|y|z]’. 0 = unavailable, 1 = available Range: 0|1 Default: No default |
|
dem_datum_rmse_x |
RMSE of DEM datum relative to file’s datum (for the x-coordinate). Range: 0...999999 Default: No default |
|
dem_datum_rmse_y |
RMSE of DEM datum relative to file’s datum (for the y-coordinate). Range: 0...999999 Default: No default |
|
dem_datum_rmse_z |
RMSE of DEM datum relative to file’s datum (for the z-coordinate). Range: 0...999999 Default: No default |
|
dem_datum_sample_size |
Sample size on which statistics for attributes ‘dem_datum_rmse_[x|y|z]’ are based. Range: 0...999999 Default: No default |
Point Data
dem_type: dem_point
USGS DEM point features specify a single x, y, and z coordinate. If known, the coordinate system will be specified.
|
Attribute Name |
Contents |
|---|---|
|
dem_units |
The unit of measure for the z coordinate (the altitude). Range: meters|feet Default: No default |
Statistical Data
dem_type: dem_record_C
This feature contains all the data found within record C. By definition, record C does not contain any geometry; rather, its purpose is to hold statistics about the accuracy of the data within the USGS DEM file.
|
Attribute Name |
Contents |
|---|---|
|
file_datum_stats_avail |
The code indicating the availability of the statistics in attributes ‘file_datum_rmse_[x|y|z]’. 0 = unavailable, 1 = available Range: 0|1 Default: No default |
|
file_datum_rmse_x |
RMSE of file’s datum relative to absolute datum (for the x-coordinate). Range: 0...999999 Default: No default |
|
file_datum_rmse_y |
RMSE of file’s datum relative to absolute datum (for the y-coordinate). Range: 0...999999 Default: No default |
|
file_datum_rmse_z |
RMSE of file’s datum relative to absolute datum (for the z-coordinate). Range: 0...999999 Default: No default |
|
file_datum_sample_size |
Sample size on which statistics for attributes ‘file_datum_rmse_[x|y|z]’ are based. Range: 0...999999 Default: No default |
|
dem_datum_stats_avail |
The code indicating the availability of the statistics in attributes ‘dem_datum_rmse_[x|y|z]’. 0 = unavailable, 1 = available Range: 0|1 Default: No default |
|
dem_datum_rmse_x |
RMSE of DEM datum relative to file’s datum (for the x-coordinate). Range: 0...999999 Default: No default |
|
dem_datum_rmse_y |
RMSE of DEM datum relative to file’s datum (for the y-coordinate). Range: 0...999999 Default: No default |
|
dem_datum_rmse_z |
RMSE of DEM datum relative to file’s datum (for the z-coordinate). Range: 0...999999 Default: No default |
|
dem_datum_sample_size |
Sample size on which statistics for attributes ‘dem_datum_rmse_[x|y|z]’ are based. Range: 0...999999 Default: No default |