Elevation-Derived Hydrography Data Acquisition Specifications: Tables
Elevation-Derived Hydrography Data Acquisition Specifications
Tables from Elevation-Derived Hydrography Data Acquisition Specifications Report - Techniques and Methods 11–B11
Formatted Tables in Current Revision Report
- Elevation-Derived Hydrography Data Acquisition Specifications 2024 rev. A2 (pdf)
Table 1. Horizontal Coordinate Reference System (Listed in another section).
Table 2. Vertical Coordinate Reference System (Listed in another section).
Table 3. Geometry of elevation-derived hydrography feature types.
Table 4. Attribute table structure for line hydrographic features.
Table 5. Attribute table structure for area and point hydrographic features.
Table 6. Domain values for FlowClass feature attributes.
Table 7. Domain values for Limitation feature attributes.
Table 8. FCode domain values and descriptions.
Table 9. Domain values for FClass feature attributes.
Table 10. Domain values for EClass feature attributes.
Table 11. Feature type description, associated geometry, and use classification.
Table 12. Polygon features used for hydroflattening an elevation surface.
Table 13. Hydroflattening feature and updated code.
Table 14. Examples of acceptable ancillary datasets.
Table 16. Data dictionary for EDH_Spatial_Metadata.gpkg, Elevation_Project_Polygons feature class.
Table 17. Data dictionary for EDH_Spatial_Metadata.gpkg, DEM_Limitation feature class.
Table 18. Data dictionary for EDH_Spatial_Metadata.gpkg, DPA feature class.
Table 3. Geometry of elevation-derived hydrography feature types.
| Feature type | Format | Geometry |
|---|---|---|
| Point | Vector shape | 3D point, pointZ |
| Line | Vector shape | 3D line, polylineZ |
| Polygon | Vector shape | 3D polygon, polygonZ |
Table 4. Attribute table structure for line hydrographic features.
| Attribute description | Item name | Item | Item type | Domain | Item precision |
|---|---|---|---|---|---|
| Feature class (hydrography) | FClass | Integer | Short | FClass | 4 |
| Feature class (elevation) | EClass | Integer | Short | EClass | 4 |
| Feature code | FCode | Integer | Long | FCode | 5 |
| Description | Desc | Text | Text | -- | 250 |
| Elevation source data | Source | Text | Text | -- | 128 |
| Hydrography delineation method | Method | Text | Text | -- | 250 |
| User-defined code | UserCode | Text | Text | -- | 25 |
| Free-text space for user comments | Comments | Text | Text | -- | 250 |
| User-defined code | UniqueID | Text | Text | -- | 50 |
| Digital Elevation Model (DEM) Limitation | Limitation | Integer | Short | Limitation | 1 |
| Flow Direction Determination | FlowClass | Integer | Short | FlowClass | 1 |
Table 5. Attribute table structure for area and point hydrographic features.
| Attribute description | Item name | Item | Item type | Domain | Item precision |
|---|---|---|---|---|---|
| Feature class (hydrography) | FClass | Integer | Short | FClass | 4 |
| Feature class (elevation) | EClass | Integer | Short | EClass | 4 |
| Feature code | FCode | Integer | Long | FCode | 5 |
| Description | Desc | Text | Text | -- | 250 |
| Elevation source data | Source | Text | Text | -- | 128 |
| Hydrography delineation method | Method | Text | Text | -- | 250 |
| User-defined code | UserCode | Text | Text | -- | 25 |
| Free-text space for user comments | Comments | Text | Text | -- | 250 |
| User-defined code | UniqueID | Text | Text | -- | 50 |
| Digital Elevation Model (DEM) Limitation | Limitation | Integer | Short | Limitation | 1 |
Table 6. Domain values for FlowClass feature attributes.
| Domain value | Feature attributes |
|---|---|
| 0 | Flow direction is unable to be determined from elevation surface. |
| 1* | Flow direction is in digitized direction, and z-values on vertices flow downslope. |
| 2 | Flow direction is in digitized direction, and z-values on vertices flow upslope. |
*This is the default value.
Table 7. Domain values for Limitation feature attributes.
| Domain value | Feature attributes |
|---|---|
| 0* | No elevation dataset limitation. |
| 1 | Elevation dataset limitation. |
*This is the default value.
Table 8. FCode domain values and descriptions.
| FCode | Desc |
|---|---|
| 0 | User-defined feature |
| 33400 | Connector |
| 33401 | Connector: Culvert |
| 33404 | Connector: Indefinite Surface |
| 33405 | Connector: Terrain Breach |
| 33410 | Connector: Non-NHD Dataset |
| 33600 | Canal/ditch |
| 36100 | Playa |
| 39000 | Lake/pond |
| 42002 | Underground Conduit |
| 42800 | Pipeline |
| 44500 | Sea/ocean |
| 45000 | Sink |
| 46000 | Stream/river |
| 46800 | Drainageway |
| 55800 | Artificial path |
Table 9. Domain values for FClass feature attributes.
| Domain value | Feature attributes |
|---|---|
| 1* | Hydrography feature defined within the collection criteria of the elevation-derived hydrography specifications. |
| 2 | Hydrography feature captured outside the collection criteria of the elevation-derived hydrography specifications. |
| 9 | Nonhydrography feature. |
*This is the domain value.
Table 10. Domain values for EClass feature attributes.
| Domain value | Feature attributes | |
|---|---|---|
| 0 | Not used for elevation derivative. | Not used for elevation derivative. Includes features that are above the surface (such as pipelines), on the surface, or below the surface but should not be hydro-enforced (such as underground conduits). |
| 11 | Polygon created using a lidar source hydroflattening breakline. | For use with lidar source elevation, where an unmodified hydroflattening elevation breakline was used to make a waterbody. |
| 12 | Polygon created using a smoothed IfSAR source hydroflattening breakline. | For use with IfSAR source elevation, where the hydroflattening elevation breakline was smoothed to make the waterbody boundary. The waterbody boundary should match the hydroflattened surface within 2 pixels after smoothing. |
| 13 | Polygon created where no hydroflattening breakline is suitable or available. | For use where there is no hydroflattening elevation breakline or the hydroflattening elevation breakline is unsuitable for creating waterbodies. If a hydroflattening elevation breakline is available, extensive editing must be done to use it as a waterbody boundary. |
| 2* | Linear feature that follows elevation surface. | Linear hydrographic features that follow the elevation surface. |
| 3 | Linear feature used for breaching. | Linear features below ground level used for breaching—Examples include connectors through dams, culvert connectors, and terrain breach connectors. Used for elevation derivatives. |
*This is the default value.
Table 11. Feature type description, associated geometry, and use classification.
| Desc | FCode | Geometry type | FClass Domain value | EClass Domain value |
|---|---|---|---|---|
| Artificial path | 55800 | 3D line, polylineZ (creates network connectivity) | 1 | 2 |
| Canal/ditch | 33600 | 3D line, polylineZ (does not connect primary network features) | 2 | 0 |
| Canal/ditch | 33600 | 3D line, polylineZ (creates network connectivity) | 1 | 2 |
| Canal/ditch | 33600 | 3D polygon, polygonZ (polygon matches hydroflattening breaklines, breakline used) | 1 | 11 |
| Canal/ditch | 33600 | 3D polygon, polygonZ (polygon based on hydroflattening surface, breakline edits required) | 1 | 12 |
| Canal/ditch | 33600 | 3D polygon, polygonZ (no hydroflattening breakline available, polygon newly captured) | 1 | 13 |
| Connector | 33400 | 3D line, polylineZ | 1 | 3 |
| Connector | 33400 | 3D line, polylineZ | 1 | 0 |
| Connector | 33400 | 3D line, polylineZ | 2 | 0 |
| Connector: Culvert | 33401 | 3D line, polylineZ | 1 | 3 |
| Connector: Indefinite surface | 33404 | 3D line, polylineZ (creates network connectivity) | 1 | 2 |
| Connector: Indefinite surface | 33404 | 3D line, polylineZ (creates network connectivity) | 1 | 0 |
| Connector: Non-NHD Dataset | 33410 | 3D line, polylineZ (does not connect primary network features) | 2 | 0 |
| Connector: Terrain breach | 33405 | 3D line, polylineZ | 1 | 3 |
| Drainageway | 46800 | 3D line, polylineZ (creates network connectivity) | 1 | 2 |
| Lake/pond | 39000 | 3D polygon, polygonZ (polygon matches hydroflattening breaklines, breakline used) | 1 | 11 |
| Lake/pond | 39000 | 3D polygon, polygonZ (polygon based on hydroflattening surface, breakline edits required) | 1 | 12 |
| Lake/pond | 39000 | 3D polygon, polygonZ (no hydroflattening breakline available, polygon newly captured) | 1 | 13 |
| Pipeline | 42800 | 3D line, polylineZ (does not connect primary network features) | 2 | 0 |
| Pipeline | 42800 | 3D line, polylineZ (creates network connectivity) | 1 | 2 |
| Pipeline | 42800 | 3D line, polylineZ (creates network connectivity) | 1 | 3 |
| Playa | 36100 | 3D polygon, polygonZ | 1 | 0 |
| Sea/Ocean | 44500 | 3D polygon, polygonZ (polygon matches hydroflattening breaklines, breakline used) | 1 | 11 |
| Sea/Ocean | 44500 | 3D polygon, polygonZ (polygon based on hydroflattening surface, breakline edits required) | 1 | 12 |
| Sea/Ocean | 44500 | 3D polygon, polygonZ (no hydroflattening breakline available, polygon newly captured) | 1 | 13 |
| Sink | 45000 | 3D point, pointZ | 1 | 0 |
| Stream/River | 46000 | 3D line, polylineZ (creates network connectivity) | 1 | 2 |
| Stream/River | 46000 | 3D polygon, polygonZ (polygon matches hydroflattening breaklines, breakline used) | 1 | 11 |
| Stream/River | 46000 | 3D polygon, polygonZ (polygon based on hydroflattening surface, breakline edits required) | 1 | 12 |
| Stream/River | 46000 | 3D polygon, polygonZ (no hydroflattening breakline available, polygon newly captured) | 1 | 13 |
| Underground Conduit | 42002 | 3D line, polylineZ (creates network connectivity) | 1 | 0 |
| User Defined Feature | 0 | 3D line, polylineZ (does not connect primary network features) | 9 | 0 |
Table 12. Polygon features used for hydroflattening an elevation surface.
| Desc | FCode |
|---|---|
| Canal/ditch | 33600 |
| Lake/pond | 39000 |
| Sea/ocean | 44500 |
| Stream/river | 46000 |
Table 13. Hydroflattening feature and updated code.
| Hydroflattening feature | Hydroflattening short description (see Lidar Base Specification for all cases) | Elevation-derived hydrographic feature | FCode | Elevation-derived hydrographic feature 2D (polygon) description |
|---|---|---|---|---|
| Inland ponds and lakes | Waterbodies with a surface area of 0.8 ha (2 acres) or greater (approximately equal to a round pond 100 m in diameter) at the time of collection shall be flattened. | Lake/pond | 39000 | A standing body of water with a predominantly natural shoreline surrounded by land. |
| Inland streams and rivers | Streams and rivers of a 30 m or greater nominal width shall be flattened. | Stream/river | 46000 | A body of flowing water. |
| Tidal waterbodies | Tidal waterbodies are defined as any waterbody that is affected by tidal variations, including oceans, seas, gulfs, bays, inlets, salt marshes, and large lakes. | Sea/ocean | 44500 | The great body of saltwater that covers much of the Earth. |
| Nontidal boundary waterbodies | Boundary waterbodies are waterbodies that contain some or all of the DPA. • Boundary waterbodies may be any type of waterbody but are virtually always large in area or width.
| Any large 2D features at the edge of the DPA. Exceptions are tidal waterbodies: sea/ocean. | 39000, 43600, 46000 | A 2D feature that is not wholly contained within the DPA and is therefore only partially delineated. |
Table 14. Examples of acceptable ancillary datasets.
| Required/ recommended | Source | Resolution | Comments | Use |
|---|---|---|---|---|
| Required | Subset of NHD features required for capture in the elevation-derived hydrography–AS | 1:24,000 or better | Download most recent version from The National Map | Use as a guide for minimum features that must be collected. |
| Required | Elevation surfaces, bare-earth digital elevation model | 1 meter | Should be created from bare-earth lidar points. | All features collected must match the surface of the lidar bare-earth surface. |
| Required | Watershed Boundary Dataset, 12-digit hydrologic units | 1:24,000 or better | Download most recent version from The National Map | Use as a guide for minimum density of features that must be collected. Buffer the watershed areas to capture a complete network. |
| Recommended | Subset of NHD features not required for capture in the elevation-derived hydrography –AS | 1:24,000 or better | Download most recent version from The National Map, or use web feature service | Use as a reference for features within the NHD with FCodes not required by elevation-derived hydrography –AS, but potentially useful for understanding the hydrology of the area. |
| Recommended | Intensity images from same source as lidar surfaces | 1 meter | Should be created from bare-earth intensity values | From the same source as the elevation surface. Can be used as imagery. Water and wet areas are often visible. |
| Recommended | Leaf-off orthoimagery | ≤1 meter | Image date should be as close to the lidar collection date as possible | Visible features below tree canopy. Helpful to identify roads and stream intersections. |
| Recommended | Leaf-on orthoimagery | ≤1 meter | Image date should be as close to the lidar collection date as possible | Riparian zones are often obvious in imagery. |
| Recommended | Near infrared band for vegetation | ≤1 meter | Image date should be as close to the lidar collection date as possible | Helpful for vegetation identification. |
| Recommended | Transportation layer | 1:24,000 or better | State or local government data tends to be higher resolution and more current than Federal road and highway datasets | Used for identification of culvert features, and for delineation of headwater streams near roads or railroads (see “Culverts” and “Headwaters at Roads” subsections of “Special Cases” in the “Delineation of Hydrographic Features” section). |
| Recommended | Bridge and culvert datasets from DOT or others | 1:24,000 or better | May be difficult to find for many States. Often coarser resolution but useful as a guide. National datasets exist (National Bridge Inventory, Federal Highway Administration, U.S. Department of Transportation) but are coarse | Use as a guide for culvert identification. |
| Recommended | Dam locations | 1:24,000 or better | National dataset coarser than lidar; for example, National Inventory of Dams | Use as a guide for dam identification. |
| Recommended | Lidar full point cloud | 1 meter | Should be from the same lidar collection | Helpful to distinguish features, or buildings that may be in flowpaths. |
| Recommended | Storm sewer systems and underground systems in urban areas | 1:24,000 or better | Source date should be as close to the lidar collection date as possible | Use to identify subsurface connections, pipelines, culverts. |
| Recommended | Building footprints | 1:24,000 or better | Source data should be as close to the lidar collection date as possible. Microsoft building footprints are available nationally but may be several years old. Local or State agencies may have more recently updated building footprints. | Use to route hydrography around buildings. Can be useful in areas where buildings were removed in the bare earth surface, but a pit was created as an artifact of the filtering. |
| Recommended | Randolph Glacier Inventory | NA | Download most recent version from GLIMS: Global Land Ice Measurements from Space | Use to find glacier locations. See section on “Ice Masses” |
| Recommended | National Wetlands Inventory | NA | Download most current version from the Fish and Wildlife Service. | Use to identify open water. |
Table 15. Data dictionary for EDH_Spatial_Metadata.gpkg Final_Deliverable_Project_Area feature class.
| Field | Type | Length | Definition |
|---|---|---|---|
| OBJECTID | Object ID | - | Automatically generated sequential unique whole numbers. |
| geometry | Geometry | - | The type of geometry—point, line, polygon, multipoint, or multipatch that the table stores. |
| producer | Text | 100 | Name of organization submitting elevation-derived hydrography |
| ptsid | Long | - | USGS Product Tracking System ID for 3DHP Project |
| wokunitid | Long | - | USGS Product Tracking System ID for 3DHP Project |
| edhspecversion | Text | 10 | Name and version of specification used |
| edhschemaversion | Text | 10 | Name and version of schema used |
Table 16. Data dictionary for EDH_Spatial_Metadata.gpkg, Elevation_Project_Polygons feature class.
| Field | Type | Length | Definition |
|---|---|---|---|
| OBJECTID | Object ID | -- | Automatically generated sequential unique whole numbers. |
| shape | Geometry | -- | The type of geometry—point, line, polygon, multipoint, or multipatch that the table stores. |
| ptsid | Long | -- | USGS Product Tracking System ID for 3DEP Project |
| source | Text | 200 | Free text description of elevation data source. |
| workunit | Text | 500 | USGS Product Tracking System work-unit name for 3DEP Project |
| workunitid | long | -- | USGS Product Tracking System work-unit identifier for 3DEP Project |
| dldate | date | -- | date the data were downloaded from source. |
| html | text | 100 | URL for source data |
| collectstart | date | -- | USGS 3DEP WESM elevation source data collection start date. |
| collectend | date | -- | USGS 3DEP WESM elevation source data collection end date. |
| otherdate | text | 100 | Free text description of dates associated with other elevation source data. |
| ql | text | 50 | ASPRS quality level of data. https://www.asprs.org/a/society/divisions/pad/Accuracy/Draft_ASPRS_Accu… |
Table 17. Data dictionary for EDH_Spatial_Metadata.gpkg, DEM_Limitation feature class.
| Field | Type | Length | Definition |
|---|---|---|---|
| OBJECTID | Object ID | -- | Automatically generated sequential unique whole numbers. |
| geometry | Geometry | -- | The type of geometry—point, line, polygon, multipoint, or multipatch that the table stores. |
| workunitid | Long | -- | USGS Product Tracking System ID for 3DHP Project |
| Explanation | Text | 250 | Explanation describing why the area of the DEM is unsuitable for deriving hydrography. |
Table 18. Data dictionary for EDH_Spatial_Metadata.gpkg, DPA feature class.
| Field | Type | Length | Definition |
|---|---|---|---|
| OBJECTID | Object ID | -- | Automatically generated sequential unique whole numbers. |
| geometry | Geometry | -- | The type of geometry—point, line, polygon, multipoint, or multipatch that the table stores. |
| workunitid | Long | -- | USGS Product Tracking System ID for 3DHP Project |
| hu8 | Text | 8 | HU8 number |
| todate | Date | -- | Date of contract or agreement to work on elevation-derived hydrography project |
Table 19. Standard Comments
| Reference | Comment |
| Depression Special Case | Downstream monotonicity cannot be enforced through depressions in the surface. |
| Inclusion or Omission of NHD Waterbody Special Case | NHD waterbody included in updated location. |
| Inclusion or Omission of NHD Waterbody Special Case | NHD Feature not present on elevation surface. |
| Inclusion or Omission of NHD Waterbody Special Case | The breakline corresponding to this NHD Waterbody does not meet the minimum size capture conditions. |
| Infrastructure Special Case | Infrastructure - unknown subsurface connection |
| Infrastructure Special Case | Infrastructure - subsurface connection. |
| Ice Masses Special Case | Ice Mass Connectivity. |
| Ice Masses Special Case | Ice Mass Connectivity. Monotonicity cannot be enforced. |