NHD Event Data Dictionary
The data structure of events in the Reach Address Database are patterned upon the event table format defined by the USGS NHD 2.2 schema . Several tools now exist to create hydrologic events using the NHD standard. The following data dictionary is provided as an aid in understanding this format. Note that the Cycle_Year, Start_Date and End_Date fields are not currently part of the USGS NHD 2.1 event model but are vital in the submission of event data to the RAD.
NHD Point Event
| Field Name | Data Type | NULL? | Description |
|---|---|---|---|
| Permanent_Identifier | String 40 | N | 40-char GUID value that uniquely identifies the occurrence of each event. |
| EventDate | Date | Y | Date an event was created. |
| ReachCode | String 14 | Y | Reach Code on which the event is located. |
| ReachSMDate | Date | Y | Reach Version Date. |
| ReachResolution | Long Integer | Y | Source resolution. See NHD Resolution Domain Table for the list of possible values. |
| Feature_Permanent_Identifier | String 40 | Y | Permanent_Identifier of NHD feature that is referenced as an event. |
| FeatureClassRef | Long Integer | Y | NHD feature class that holds FeatureComID. See NHD Feature Class Reference Domain Table for the list of possible values. |
| Source_Originator | String 130 | N | Originator of the event. |
| Source_DataDesc | String 100 | Y | Description of the entity. |
| Source_FeatureID | String 40 | N | Identifier of the entity used in the source data. |
| FeatureDetailURL | String 255 | Y | URL where detailed event entity data can be found. |
| Measure | Double | Y | Point measure that the event occurs at upon the reached flowline. |
| EventType | Long Integer | N | Value indicating the program for which the event has been created. See RAD Programs for values of each program. |
| EventOffset | Double | Y | Event display offset. |
| Cycle_Year | String 4 | Y | The cycle year of the event data being submitted. Not all programs have the cycle year concept. For those programs with a cycle year concept this field is mandatory. |
| Start_Date | Date | N | The start date indicates the date on which the event becomes valid for the program. All program events must have a start date. For programs tracking this value only via year, use April 1st for month and day. |
| End_Date | Date | Y | The end date indicates the date on which the event is no longer valid or is superceded by new event data in a new record. For event submitters, this field will only be used when submitting historical data to be place directly into the RAD archive tables. Note that the majority of submissions will not utilize this field. |
| Shape | Geometry | N | Acceptable geometry data types include MDSYS.SDO_GEOMETRY, SDE.ST_GEOMETRY, BLOB of Geographic Markup Language (GML) 2.1, BLOB of Well-Known-Text (WKT) or Well-Known-Text binary format (WKB). Submissions using shapefiles or file geodatabases do not need to add this field. All geometries should utilize the federal standard NAD83 coordinate system or supply specific documentation on projection and datum used. |
| Objectid | Long Integer | N | Vendor-required unique numeric key. |
NHD Line Event
| Field Name | Data Type | NULL? | Description |
|---|---|---|---|
| Permanent_Identifier | String 40 | N | 40-char GUID value that uniquely identifies the occurrence of each event. |
| EventDate | Date | Y | Date an event was created. |
| ReachCode | String 14 | Y | Reach Code on which the event is located. |
| ReachSMDate | Date | Y | Reach Version Date. |
| ReachResolution | Long Integer | Y | Source resolution. See NHD Resolution Domain Table for the list of possible values. |
| Feature_Permanent_Identifier | String 40 | Y | Permanent_Identifier of NHD feature that is referenced as an event. |
| FeatureClassRef | Long Integer | Y | NHD feature class that holds FeatureComID. See NHD Feature Class Reference Domain Table for the list of possible values. |
| Source_Originator | String 130 | N | Originator of the event. |
| Source_DataDesc | String 100 | Y | Description of the entity. |
| Source_FeatureID | String 40 | N | Identifier of the entity used in the source data. |
| FeatureDetailURL | String 255 | Y | URL where detailed event entity data can be found. |
| FMeasure | Double | Y | Linear Reference starting measure of the NHD reach containing the event. |
| TMeasure | Double | Y | Linear Reference ending measure of the NHD reach containing the event. |
| EventOffset | Double | Y | Event display offset. |
| EventType | Long Integer | N | Value indicating the program for which the event has been created. See RAD Programs for values of each program. |
| Cycle_Year | String 4 | Y | The cycle year of the event data being submitted. Not all programs have the cycle year concept. For those programs with a cycle year concept this field is mandatory. |
| Start_Date | Date | N | The start date indicates the date on which the event becomes valid for the program. All program events must have a start date. For programs tracking this value only via year, use April 1st for month and day. |
| End_Date | Date | Y | The end date indicates the date on which the event is no longer valid or is superceded by new event data in a new record. For event submitters, this field will only be used when submitting historical data to be place directly into the RAD archive tables. Note that the majority of submissions will not utilize this field. |
| Shape | Geometry | Y | Acceptable geometry data types include MDSYS.SDO_GEOMETRY, SDE.ST_GEOMETRY, BLOB of Geographic Markup Language (GML) 2.1, BLOB of Well-Known-Text (WKT) or Well-Known-Text binary format (WKB). Submissions using shapefiles or file geodatabases do not need to add this field. All geometries should utilize the federal standard NAD83 coordinate system or supply specific documentation on projection and datum used. |
| ObjectID | Long Integer | N | Vendor-required unique numeric key. |
NHD Area Event
| Field Name | Data Type | NULL? | Description |
|---|---|---|---|
| Permanent_Identifier | String 40 | N | 40-char GUID value that uniquely identifies the occurrence of each event. |
| EventDate | Date | Y | Date an event was created. |
| ReachCode | String 14 | Y | Reach Code on which the event is located. |
| ReachSMDate | Date | Y | Reach Version Date. |
| ReachResolution | Long Integer | Y | Source resolution. See NHD Resolution Domain Table for the list of possible values. |
| Feature_Permanent_Identifier | String 40 | Y | Permanent_Identifier of NHD feature that is referenced as an event. |
| FeatureClassRef | Long Integer | Y | NHD feature class that holds FeatureComID. See NHD Feature Class Reference Domain Table for the list of possible values. |
| Source_Originator | String 130 | N | Originator of the event. |
| Source_DataDesc | String 100 | Y | Description of the entity. |
| Source_FeatureID | String 40 | N | Identifier of the entity used in the source data. |
| FeatureDetailURL | String 255 | Y | URL where detailed event entity data can be found. |
| EventType | Long Integer | N | Value indicating the program for which the event has been created. See RAD Programs for values of each program. |
| Cycle_Year | String 4 | Y | The cycle year of the event data being submitted. Not all programs have the cycle year concept. For those programs with a cycle year concept this field is mandatory. |
| Start_Date | Date | N | The start date indicates the date on which the event becomes valid for the program. All program events must have a start date. For programs tracking this value only via year, use April 1st for month and day. |
| End_Date | Date | Y | The end date indicates the date on which the event is no longer valid or is superceded by new event data in a new record. For event submitters, this field will only be used when submitting historical data to be place directly into the RAD archive tables. Note that the majority of submissions will not utilize this field. |
| Shape | Geometry | N | Acceptable geometry data types include MDSYS.SDO_GEOMETRY, SDE.ST_GEOMETRY, BLOB of Geographic Markup Language (GML) 2.1, BLOB of Well-Known-Text (WKT) or Well-Known-Text binary format (WKB). Submissions using shapefiles or file geodatabases do not need to add this field. All geometries should utilize the federal standard NAD83 coordinate system or supply specific documentation on projection and datum used. |
| ObjectID | Long Integer | N | Vendor-required unique numeric key. |
NHD Feature to Metadata
| Field Name | Data Type | NULL? | Description |
|---|---|---|---|
| Permanent_Identifier | String 40 | N | 40-char GUID value that uniquely identifies the occurrence of each event. |
| Meta_ProcessID | String 40 | N | 40-char GUID value that uniquely identifies a metadata process description. |
| ObjectID | Long Integer | N | Vendor-required unique numeric key. |
NHD Metadata
| Field Name | Data Type | NULL? | Description |
|---|---|---|---|
| Meta_ProcessID | String 40 | N | 40-char GUID value that uniquely identifies a metadata process description. |
| ProcessDescription | String 4000 | Y | Explanation of the process used to create the data, including parameters or tolerances. |
| ProcessDate | Date | Y | Date when the data was completed. |
| AttributeAccuracyReport | String 1800 | Y | Explanation of entities and assignments of values in dataset. |
| LogicalConsistencyReport | String 1000 | Y | Explanation of fidelity and relationships in dataset, and tests used. |
| CompletenessReport | String 2400 | Y | Information about omissions, criteria, definitions used to derive dataset. |
| HorizPositionalAccuracyReport | String 3100 | Y | Horizontal coordinate measurements and description of test used. |
| VertPositionalAccuracyReport | String 3100 | Y | Vertical coordinate measurements and description of test used. |
| MetadataStandardName | String 100 | Y | Name of the metadata standard used to document the dataset. |
| MetadataStandardVersion | String 30 | Y | Identification of the version of the metadata standard used to document it. |
| MetadataDate | Date | Y | Date the metadata was last created or updated. |
| DatasetCredit | String 4000 | Y | Recognition of those who contributed to the dataset. |
| ContactOrganization | String 100 | Y | Name or organization to which type of contact applies. |
| AddressType | String 40 | Y | Information provided about the address, i.e. mailing, physical, etc. |
| Address | String 100 | Y | Address line for the address. |
| City | String 40 | Y | City of the address. |
| StateOrProvince | String 30 | Y | State or province of the address. |
| PostalCode | String 20 | Y | ZIP or other postal code of the address. |
| ContactVoicetelephone | String 40 | Y | Telephone number to reach organization or individual. |
| ContactInstructions | String 120 | Y | Supplemental instructions to contact organization or individual. |
| ContactEmailAddress | String 40 | Y | Email address to reach organization or individual. |
| ObjectID | Long Integer | N | Vendor-required unique numeric key. |
NHD Source Citation
| Field Name | Data Type | NULL? | Description |
|---|---|---|---|
| Source_DatasetID | String 40 | N | Unique permanent ID value which uniquely identifies a source dataset used. |
| Title | String 255 | Y | Name by which the dataset is known. |
| SourceCitationAbbreviation | String 255 | Y | Short form alias for source citation. |
| Originator | String 400 | Y | Name of organization or individual who developed the dataset. |
| PublicationDate | Date | Y | Date the dataset is published or made available for release. |
| BeginningDate | Date | Y | First year of the event (if range of dates applies). |
| EndingDate | Date | Y | Last year of the event (if range of dates applies). |
| SourceContribution | String 255 | Y | Brief statement identifying information contributed by source to dataset. |
| SourceScaleDenominator | Long Integer | Y | Denomination of representative fraction on a map. |
| TypeOfSourceMedia | String 255 | Y | The medium of the source dataset, i.e. paper, CD-ROM, online, etc. |
| CalendarDate | Date | Y | The year (if single date applies). |
| SourceCurrentnessReference | String 255 | Y | The basis on which the source time period of content information of the source data set is determined. |
| Meta_ProcessID | String 40 | N | 40-char GUID value that uniquely identifies a metadata process description. |
| ObjectID | Long Integer | N | Vendor-required unique numeric key. |
NHD Reach Resolution Domain Table
| Value | Description |
|---|---|
| 1 | Local Resolution |
| 2 | High Resolution |
| 3 | Medium Resolution |
NHD Feature Class Reference Domain Table
| Value | Description |
|---|---|
| 1 | NHDArea |
| 2 | NHDFlowline |
| 3 | NHDLine |
| 4 | NHDPoint |
| 5 | NHDWaterbody |