Canadian Digital Elevation Data (CDED) Feature Representation

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).

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