Metadata: Identification_Information: Citation: Citation_Information: Originator: Alexander C. Seymour Originator: Kara S. Doran Publication_Date: 20250509 Title: North Carolina Synthetic Elevation Checkpoints, Complex Version Edition: 1.0 Geospatial_Data_Presentation_Form: vector and tabular digital data Larger_Work_Citation: Citation_Information: Originator: Alexander C. Seymour Originator: Kara S. Doran Publication_Date: 20250509 Title: Synthetic Elevation Checkpoints, North Carolina Series_Information: Series_Name: U.S. Geological Survey data release Issue_Identification: doi:10.5066/P1HZA84J Publication_Information: Publication_Place: St. Petersburg, FL Publisher: U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center Online_Linkage: https://doi.org/10.5066/P1HZA84J Description: Abstract: The geospatial datasets describe positions, elevations, and uncertainties for synthetic elevation checkpoints generated across the developed coastline of North Carolina. Two datasets are provided as point shapefiles and American Standard Code for Information Interchange (ASCII) tables, and each contains synthetic checkpoints generated using a time series (1996-2018) of digital elevation models (DEMs), a road vector network, and a classified landcover dataset. The first 'simple' dataset contains ~10,000 checkpoints and the second 'complex' dataset contains ~7,000 checkpoints. The latter dataset was derived using more demanding processing settings and as a result, checkpoints are more accurate, but fewer in number. These datasets can be used to validate remotely sensed topographic surveys such as lidar and photogrammetry-derived DEMs and digital surface models (DSMs). The methods used to generate these data followed the process outlined in "Automated Generation of a Synthetic Elevation Checkpoint Network across the North Carolina Coastline, USA" by Seymour and others (2025). Purpose: To provide reference elevations to validate and characterize the accuracy of new and historical remotely-sensed topographic surveys. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19961009 Ending_Date: 20181002 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -78.516538 East_Bounding_Coordinate: -75.462562 North_Bounding_Coordinate: 36.540132 South_Bounding_Coordinate: 33.847425 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:a05dc2e1-8480-437b-98e7-8b22a3037be5 Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme_Keyword: oceans Theme_Keyword: environment Theme_Keyword: structure Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: hazards Theme_Keyword: marine geology Theme_Keyword: ocean sciences Theme_Keyword: coastal processes Theme_Keyword: erosion Theme_Keyword: floods Theme_Keyword: geospatial datasets Theme_Keyword: time series datasets Theme_Keyword: time series analysis Theme_Keyword: remote sensing Theme_Keyword: lidar Theme_Keyword: aerial photography Theme_Keyword: structure from motion Theme_Keyword: digital elevation models Theme_Keyword: earth sciences Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: St. Petersburg Coastal and Marine Science Center Theme_Keyword: SPCMSC Theme_Keyword: Coastal and Marine Hazards and Resources Program Theme_Keyword: CMHRP Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: State of North Carolina Access_Constraints: No access constraints. Please see 'Distribution Information' for details. Use_Constraints: These data are marked with a Creative Common CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Kara S. Doran Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: Saint Petersburg State_or_Province: FL Postal_Code: 33701 Country: United States Contact_Voice_Telephone: 727-502-8117 Contact_Facsimile_Telephone: 727-502-8001 Contact_Electronic_Mail_Address: kdoran@usgs.gov Native_Data_Set_Environment: Windows 10 Enterprise 21H2 (Build 19044.1826); Esri ArcGIS Pro 3.0.3; Microsoft Excel Version 2402 Cross_Reference: Citation_Information: Originator: Alexander C. Seymour Originator: Christine Kranenburg Originator: Kara S. Doran Publication_Date: 20250507 Title: Automated Generation of a Synthetic Elevation Checkpoint Network across the North Carolina Coastline Series_Information: Series_Name: SSRN Issue_Identification: preprint Publication_Information: Publication_Place: Online Publisher: Elsevier Online_Linkage: https://doi.org/10.2139/ssrn.5242093 Data_Quality_Information: Logical_Consistency_Report: Uncertainty estimates were produced for all checkpoint elevations. Complex and simple points may have the same CheckpointID, but the elevation and uncertainty estimates differ. Completeness_Report: This dataset is considered complete for the information presented, as described in the abstract section. Users are advised to read the rest of the metadata record carefully for additional details. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Horizontal accuracies were not calculated and are not applicable for these data. Horizontal positions are referenced to the North American Datum of 1983 National Spatial Reference System (2011) (NAD 1983 [2011]) coordinate system. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Uncertainties for checkpoint elevations are described by 95% confidence intervals. Confidence intervals are standard diagnostic metrics produced by generalized linear regressions. For more information on how these regressions were calculated, see Seymour and others (2025). Vertical positions are referenced to the North American Vertical Datum of 1988 (Geoid 12B). Lineage: Process_Step: Process_Description: Synthetic elevation checkpoints were generated by processing a time series of DEMs, a road vector network, and a classified landcover raster in ArcGIS Pro. Synthetic checkpoints were filtered by a number of quality thresholds and metrics including confidence interval, the presence of elevation trends over time, and a minimum number of contributing surveys. The 'complex' checkpoint version used a more demanding set of quality thresholds and metrics that result in a fewer number of higher accuracy checkpoints than the 'simple' version. The specific details, methods, and parameters used to generate the synthetic elevation checkpoints in this data release can be found in Seymour and others (2025). The 'complex' synthetic checkpoint ASCII table was generated by inputting the point feature class into the 'Feature Class to ASCII' ArcGIS Pro geoprocessing tool. Synthetic checkpoints should not be used to assess the accuracy of elevation datasets that were used to generate the synthetic checkpoints because the independence assumption is violated. See Table 1 and section 2.3 in Seymour and others (2025) for the list of published elevation models that were used to generate the synthetic checkpoints. When validating a digital surface model such as those produced by structure from motion photogrammetry, review section 3.3 and 4.1 of Seymour and others (2025) for considerations on how to best apply synthetic checkpoints. Process_Date: 20220823 Source_Produced_Citation_Abbreviation: NC_Synthetic_Checkpoints_GDB.gdb Source_Produced_Citation_Abbreviation: Synthetic_Complex_NC Source_Produced_Citation_Abbreviation: Synthetic_Complex_NC_ASCII_Geographic.csv Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Alexander C. Seymour Contact_Organization: U.S. Geological Survey Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: Saint Petersburg State_or_Province: FL Postal_Code: 33701 Country: United States Contact_Voice_Telephone: 727-502-8122 Contact_Facsimile_Telephone: 727-502-8001 Contact_Electronic_Mail_Address: aseymour@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 6,853 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000000001 Longitude_Resolution: 0.000000001 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: NAD 1983 (2011) Ellipsoid_Name: D NAD 1983 2011 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257222101 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum 1988 Altitude_Resolution: 0.001 Altitude_Distance_Units: meters Altitude_Encoding_Method: Attribute values Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: NC_Synthetic_Checkpoints_GDB.gdb, Synthetic_Complex_NC, Synthetic_Complex_NC_ASCII_Geographic.csv Entity_Type_Definition: File geodatabase feature class (.gdb) and comma-separated values file (.csv) of the synthetic elevation checkpoints for North Carolina. Entity_Type_Definition_Source: USGS Attribute: Attribute_Label: OBJECTID Attribute_Definition: Internal feature number. This attribute is only present in the feature class dataset. Attribute_Definition_Source: Esri Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: Shape Attribute_Definition: Feature geometry. This attribute is only present in the feature class dataset. Attribute_Definition_Source: Esri Attribute_Domain_Values: Unrepresentable_Domain: Point Attribute: Attribute_Label: CheckpointID Attribute_Definition: An ID for each synthetic elevation checkpoint. The CheckpointID attribute/field is not consecutive because the initial series of checkpoints were winnowed during confidence filtering processes (see Seymour and others, 2025 for details). Some 'simple' and 'complex' checkpoints occur at the same location and thus have the same CheckpointID. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 67 Range_Domain_Maximum: 39,888 Attribute: Attribute_Label: CheckpointElevation Attribute_Definition: The elevation of the synthetic checkpoint, in meters (NAVD 88). 'Simple' and 'complex' checkpoints with the same CheckpointID may have different elevations because they underwent different confidence and outlier filtering thresholds (see Seymour and others, 2025 for details). Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.466 Range_Domain_Maximum: 14.709 Attribute: Attribute_Label: CheckpointElevationCI95 Attribute_Definition: The 95% confidence interval representing the vertical uncertainty of the synthetic checkpoint elevation, in meters. 'Simple' and 'complex' checkpoints with the same CheckpointID may have different uncertainties because they underwent different confidence and outlier filtering thresholds (see Seymour and others, 2025 for details). Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.003 Range_Domain_Maximum: 0.039 Attribute: Attribute_Label: ContributingSurveys Attribute_Definition: The number of surveys from the time series (see Seymour and others, 2025) that are contributing to the synthetic checkpoint elevation. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 5 Range_Domain_Maximum: 8 Attribute: Attribute_Label: XCoord Attribute_Definition: The x-coordinate of the point in meters NAD 1983 (2011). This attribute is only present in the ASCII dataset. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -78.5165382 Range_Domain_Maximum: -75.46256239 Attribute: Attribute_Label: YCoord Attribute_Definition: The y-coordinate of the point in meters NAD 1983 (2011). This attribute is only present in the ASCII dataset. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 33.84742532 Range_Domain_Maximum: 36.54013189 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center Contact_Person: USGS SPCMSC Data Management Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: Saint Petersburg State_or_Province: FL Postal_Code: 33701 Country: United States Contact_Voice_Telephone: 727-502-8000 Contact_Electronic_Mail_Address: gs-g-spcmsc_data_inquiries@usgs.gov Resource_Description: NC_Synthetic_Checkpoints_GDB.gdb, Synthetic_Complex_NC, Synthetic_Complex_NC_ASCII_Geographic.csv Distribution_Liability: Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: comma-delimited text, file geodatabase (Esri) Format_Version_Number: ArcGIS Pro 3.0.3 File_Decompression_Technique: The data download file is compressed and must be unzipped using software such as WinZip, 7Zip, etc. before use. Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P1HZA84J/data/NC_Synthetic_Elevation_Checkpoints.zip Fees: None Technical_Prerequisites: The geodatabase feature class and ArcGIS Map Package were created for the use within Esri ArcGIS Pro software (3.0.3 or newer). The ASCII table data were created for the use within Microsoft Excel, or similar text viewers, such as Notepad. Metadata_Reference_Information: Metadata_Date: 20250509 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center Contact_Person: USGS SPCMSC Data Management Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: Saint Petersburg State_or_Province: FL Postal_Code: 33701 Country: United States Contact_Voice_Telephone: 727-502-8000 Contact_Electronic_Mail_Address: gs-g-spcmsc_data_inquiries@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time