Feature Representation

In addition to the generic FME feature attributes that FME Workbench adds to all features (see About Feature Attributes), this format adds the format-specific attributes described in this section.

CDED raster features are specified by a matrix of x, y, and z coordinates. If known, the coordinate system will be specified.

All CDED features contain a cded_type attribute, which identifies the geometric type.

Attribute Name

Contents

cded_type

The CDED geometric type of this entity. This is always cded_raster.

cded_file_name

This is a string that specifies the basename of the raster file.

cded_producer

This is a string that specifies the producer of the data.

cded_process_code

This is a one-byte integer that specifies how to the data is processed.

Range: 1...8

Default: 8

cded_origin_code

This is a 4-character string that specifies the mapping origin.

cded_level_code

This is an integer defining the DEM level. This field is always set to 1 for 1:50,000 and 1:250,000 CDED.

Range: 1-3

Default: 1

cded_code_defining_elevation_pattern

This is an integer specifying the regularity of the elevation pattern.

Range: regular|random

Default: regular

cded_spatial_
resolution_z

A positive real number used to specify a scale to apply to the elevation values in the z dimension. In USGS DEM data, this is stored as spatial_resolution_z. When specified for the writer, elevation values will be scaled appropriately. This value is tied to the value of cded_units; resolutions of 1 decimal place for feet and 2 decimal places for meters are permitted.

Default: 1

cded_accuracy_code_for_elevations

A number that specifies the existence of accuracy information for this dataset. 0 indicates unknown accuracy information.

Range: 0|1

Default: 0

cded_units

The unit of measure for the z coordinate (the altitude).

Range: meters|feet

Default: No default

cded_suspect_and_void_area_flag

This is a one-digit integer that indicates if the data contains void areas.

Only valid for CDED-1.

Range: 0|2

Default: Calculated based on percent void

cded_data_edition

This is a four-digit integer specifying the data edition or version used. The first two digits indicate the data edition while the last two digits indicate the specifications version.

Only valid for CDED-1.

Range: 0...9999

Default: 1021

cded_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 cded_data_edition field indicates a void.

Only valid for CDED-1.

Range: 0...100

Default: Calculated based on number of void nodes