Pennsylvania Spatial Data Access

Abstract:

This dataset is Elevation-derived hydrography (EDH) for the 140G0225F0102 PA_LowerSusquehanna_D25_H project covering work unit PA_LowerSusquehanna_3_D25. The hydrography layer contains line features representing stream rivers and polygons representing waterbodies. The EDH was derived from 1 meter lidar Digital Elevation Models. This dataset was created to meet the requirements of the USGS Elevation-derived hydrography specification, https://www.usgs.gov/core-science-systems/ngp/ss/elevation-derived-hydrography-specifications. The line features contain Elevation class (EClass) codes useful for hydro-enforcement, including culvert identification. Feature Class (FCLASS) and Feature codes (FCodes) are hydrography codes compatible with the National Hydrography Dataset (NHD).

Purpose:

The EDH data was created to be ingested into the 3DHydrography Program(3DHP), with the aim of better aligning hydrography features with 3DEP elevation datasets horizontally and vertically. These data have been created such that they may be used for hydro-enforcement.

Supplemental_Information:

This dataset represents the work unit PA_LowerSusquehanna_3_D25 of the 140G0225F0102 PA_LowerSusquehanna_D25_H project.

Currentness_Reference:

Publication date

Use_Constraints:

For internal use only by the US Geological Survey unless prior arrangements have been made.

Address:

1100 NE Circle Blvd, Suite 126

Data_Set_Credit:

USGS

Attribute_Accuracy_Report:

Attribution was based on the original National Hydrography Dataset attributions and the lidar derived ground model. All features should contain attributes defined in the USGS Elevation-derived specification.

Logical_Consistency_Report:

All features should meet EDH topology rules. 
Points, nodes, lines, and areas conform to topological rules. Lines intersect only at nodes, and all nodes anchor the ends of lines. Lines do not overshoot or undershoot other lines where they are supposed to meet. There are no duplicate lines. Gaps and overlaps among areas do not exist. 
The EDH was compared to the lidar-source bare-earth Digital Elevation Model and channels present within the surface that meet minimum mapping requirements were added to the EDH.
The EDH was compared to the original NHD for the study area and any feature from the NHD that did not have a channel representation in the DEM was not added to the EDH. 
Stream connectivity was checked and any isolated networks were verified. 
Features added without clear channels present in the DEM are allowed if added as drainageways or indefinite surface connectors, or if DEM limitations are found and documented.

Completeness_Report:

The completeness of the data is relative to the DEM from which the EDH was derived, and must match the DEM withing relevant thresholds. The goal of this product is to be vertically and horizontally integrated with the 3DEP bare earth DEM. 
Published NHD is used as a guide for feature extraction and densification, but was not used as a source to verify the presence or absence of features.

Horizontal_Positional_Accuracy_Report:

All stream/river linear features should be placed within a channel of the bare earth DEM. Waterbody features should be placed at the apparent limit or banks of the waterbody. 
If hydro-flattening is present in the source DEM, waterbodies should match the hydro-flattening breakline extent within relevant thresholds.

Vertical_Positional_Accuracy_Report:

All features should have z-values associated with every vertex. 
Linear features should be flat or flow consistently downstream. 
Z-values are at, or just below, the surface of the DEM. Exceptions are allowed to maintain monotonicity and through connectors.
Waterbodies that do not flow are flat and the z-value are at or just below the surface of the DEM at the edge of the polygon.

Source_Contribution:

Bare earth Digital Elevation Model (DEM) used for generating point, line, and polygon vector water features; identifying flat water bodies; and populating z-values.

Source_Contribution:

Bare earth Digital Elevation Model (DEM) used for generating point, line, and polygon vector water features; identifying flat water bodies; and populating z-values.

Source_Contribution:

Bare earth Digital Elevation Model (DEM) used for generating point, line, and polygon vector water features; identifying flat water bodies; and populating z-values.

Source_Contribution:

Bare earth Digital Elevation Model (DEM) used for generating point, line, and polygon vector water features; identifying flat water bodies; and populating z-values.

Source_Contribution:

Bare earth Digital Elevation Model (DEM) used for generating point, line, and polygon vector water features; identifying flat water bodies; and populating z-values.

Source_Contribution:

Bare earth Digital Elevation Model (DEM) used for generating point, line, and polygon vector water features; identifying flat water bodies; and populating z-values.

Source_Contribution:

Bare earth Digital Elevation Model (DEM) used for generating point, line, and polygon vector water features; identifying flat water bodies; and populating z-values.

Process_Description:

        Data was collected using a combination of flow directions and accumulation routines, manual digitization, and proprietary processing and QAQC methods. All data was manually reviewed.  
		    Polygons - Waterbody polygons were created using the existing lidar breaklines combined with newly digitized polygons for Lakes, Ponds, and Reservoirs  approximately > .4 hectares and streams and canals > 15m nominal width in accordance with EDH specification. 
        Additionally, all features previously existing in the NHD were captured and updated. Minimum vertex spacing is 1.5 meters.
		    Polylines - Polylines were captured in accordance with EDH specifications including all features previously existing in the NHD if evidence of the feature was present in the ground model.  Connectivity was established using geometric network tracing.  All features were traversed.

Entity_and_Attribute_Overview:

Entity and Attribute information for datasets collected for EDH version 1.5 can be found in the Elevation-Derived Hydrography Acquisition Specifications 2024 rev. A3, which is available online at https://www.usgs.gov/media/files/elevation-derived-hydrography-acquisition-specifications-2023-rev-a . Specifically, tables  1 through 8 contain Feature type descriptions, domain values and descriptions.

Entity_and_Attribute_Detail_Citation:

USGS 3D Hydrography Program, 2023,  Elevation-Derived Hydrography Acquisition Specifications 2024 rev. A3, https://www.usgs.gov/media/files/elevation-derived-hydrography-acquisition-specifications-2023-rev-a.

Terziotti, S., and Archuleta, C.M., 2022 rev A, Elevation-Derived Hydrography Acquisition Specifications: U.S. Geological Survey Techniques and Methods, book 11, chap. B11, 74 p., https://www.usgs.gov/ngp-standards-and-specifications/elevation-derived-hydrography-specifications. 

Archuleta, C.M., and Terziotti, S., 2022 rev A, Elevation-Derived Hydrography—Representation, Extraction, Attribution, and Delineation Rules: U.S. Geological Survey Techniques and Methods, book 11, chap. B12, 60 p., https://www.usgs.gov/ngp-standards-and-specifications/elevation-derived-hydrography-specifications.

Address:

115 Land and Water building

Distribution_Liability:

The USER shall indemnify, save harmless, and, if requested, defend those parties involved with the development and distribution of this data, their officers, agents, and employees from and against any suits, claims, or actions for injury, death, or property damage arising out of the use of or any defect in the FILES or any accompanying documentation. Those parties involved with the development and distribution excluded any and all implied warranties, including warranties or merchantability and fitness for a particular purpose and makes no warranty or representation, either express or implied, with respect to the FILES or accompanying documentation, including its quality, performance, merchantability, or fitness for a particular purpose. The FILES and documentation are provided "as is" and the USER assumes the entire risk as to its quality and performance. Those parties involved with the development and distribution of this data will not be liable for any direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the FILES or any accompanying documentation

Address:

*Street Address*

Elevation Derived Hydrography for 140G0225F0102 PA_LowerSusquehanna_D25_H PA_LowerSusquehanna_3_D25