Elevation-Derived Hydrography Data Acquisition Specifications: Feature Codes and Values Requirements

Feature codes indicate hydrography types and how the features integrate with the elevation surface from which they were derived. The complete set of domain values required for this specification is provided in Table 6, Table 7, Table 8, Table 9, and Table 10. The fields, domains, and minimum feature collection requirements for each required feature are further defined in Appendix 1.

3DEP Light Detection and Ranging Base Specification Hydroflattening Features

The hydroflattening breaklines collected for lidar source data projects (U.S. Geological Survey, 2024b) can be used directly for waterbody polygon delineations. The FCodes corresponding to hydroflattening features are cross-referenced in Table 11.

Additional User-Defined Features

Additional user-defined features may be added to elevation-derived hydrography collections. User-defined features may include features with FCodes in Table 8 (other than 0) that are outside on the collection criteria. For example, canals in agricultural areas and outside the stream network may be in this category. User-defined features may also include features not listed with FCodes in Table 8 other than (0). An example may be a levee or waterfall.

• If the feature is a valid feature type, but outside the collection criteria of this specification, the following guidelines apply:
  • FClass shall be coded as 2,
  • EClass shall be coded as 0,
  • FCode shall be a valid feature from Table 8 and follow the attribute table structure from Table 4 and Table 5. The Desc field may be used to describe the additional feature.
  • A code per feature type may be added to the UserCode field.
• Additional user-defined features outside of those collected for this specification (listed in Table 8), shall be coded as follows: 
  • FClass shall be assigned a code of 9.
  • EClass shall be assigned a code of 0.
  • FCode shall be assigned a code of 0.
  • A code per feature type may be added to the UserCode field.
  • User-defined codes shall not duplicate FCodes defined in this specification.