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WESM Data Dictionary: Reason Codes: Source DEM

In addition to general attributes, the Work Unit Extent Spatial Metadata (WESM) includes information on how data in a given work unit relates to 3D Elevation Program (3DEP) elevation product specifications. This information is shown in the product status codes. Product status codes include codes for categories and reasons. Reasons for the source DEM are discussed here. 

WESM Product Status Codes: Source DEM

For more information about the product status codes, please see the WESM Introduction page


A work unit’s reason code gives the primary reason why it was assigned to a particular category. The reason codes are typically unique per category and product combination, though some codes are used for several products for some of the categories.

Links to other reason code attributes by product (links to other pages)
Quick links to sections by category (on this page)

Reason Codes for the source DEM


  • Description: Source DEM reason code
  • Definition: Used to store the reason code for the source DEM
  • Format: text
  • Length: 100 characters
  • Valid values:


Reason code

Expected to meet

Awaiting final absolute vertical accuracy assessment

Under review

Awaiting final absolute vertical accuracy assessment


Meets 3DEP source DEM requirements, or

Meets 3DEP source DEM requirements – IfSAR AK

Meets with variance

See reason code list below

Does not meet

See reason code list below

Reason codes for Meets with variance

Reason code


Breaklines do not meet specification- wetlands

Breaklines do not meet the minimum requirement in the lidar base specification in complex wetland environments. Breakline standards approved in advance in a delineated area.

Bridges not removed

Bridges not removed by agreement, variance granted.

CRS of Source DEM does not match LPC CRS

Source DEM Data not in same CRS as LPC but approved

Georeferencing does not meet specification

Georeferencing information provided; does not meet specification but is usable and accepted with a variance.

Hydroflattening - alternative criteria

Hydroflattening not required or alternative criteria approved in advance.

LPC does not meet

See LPC Reason Code

LPC meets with variance

See LPC Reason Code

Source DEM meets v1.0 or draft LBS

Source DEM created from data that meets density, classification and accuracy requirements per 3DEP requirements in USGS base spec v1.0 or draft versions.

Tile appearance - alternate

Tiles have issues such as edge artifacts, mismatches, or a quilted appearance but are still usable.

Tiles overlap - alternate

Tiles overlap but are still usable.

Void areas coded improperly

Void areas coded with wrong NODATA value or NODATA value not identified in GDAL tag.

Reason codes for Does not meet

Reason code



Breaklines are required to be delivered and meet the minimum requirement in the specification.

Bridges not removed

Bridges were not removed or the end result did not meet specification.

CRS of Source DEM does not match LPC CRS

Source DEM data not in same CRS as LPC.

DEM GSD too large

DEM GSD does not meet Lidar Base Specification Requirements. Ground sample distance of dem not supported by the nps of the LPC.

DEM not delivered

DEM required, not delivered.

Failed boundary requirements

DEMs delivered with unacceptable issues related to the DPA, such as edge mismatch, slivers missing.

Georeferencing not provided

Georeferencing information not provided or does not meet specification and is unusable.


Hydroflattening required and does not meet specification.

LPC does not meet

See LPC Reason Code

Raster format

Raster format does not meet specification.

Source DEM being made available

Source DEM of national importance being made available.

Source DEM not available

Full source DEM dataset is not available.

Tile appearance

Tiles have edge artifacts, mismatch, or have a quilted appearance.

Tiles overlap

Tiles overlap to the point of being unusable.

Unvalidated Dataset

Dataset not reviewed by USGS for inclusion into the 3D Elevation Program. Issues may exist with this dataset in addition to any known issues that may or may not have been listed.

Void areas not coded

Void areas are not coded.