WESM Data Dictionary: Reason Codes: Source DEM

By NGP Standards and Specifications

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.

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WESM Product Status Codes: Source DEM

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

Introduction

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)

Meets with variance
Does not meet

Reason Codes for the source DEM

sourcedem_reason

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

Category	Reason code
Expected to meet	Awaiting final absolute vertical accuracy assessment
Under review	Awaiting final absolute vertical accuracy assessment
Meets	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	Definition
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	Definition
Breaklines	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	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.