NHDLineEventFC

Linear Events are used to attach information about a flowline segment to the NHD. Linear events are built into the NHD Model but are not accepted back into the National Database. They are meant to be used on an individual basis. They also need a from and to location and a reachcode.

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An impaired stream is an example of a line event.

 

The attributes associated with NHDLineEventFC are as follows:

Field Name

Definition

Comments

Permanent_

Identifier

40-char GUID value that uniquely identifies the occurrence of each event in The National Map.

 

EventDate

Date an event was created.

 

ReachCode

Reach Code on which the event is located.

 

ReachSMDate

Reach Version Date

 

ReachResolution

Source resolution. 

 

Feature_Permanent_Identifier

Permanent_Identifier of NHD feature that the event is referenced to.

 

FeatureClassRef

NHD feature class that holds FeatureComID

 

Source_Originator

Originator of the event

 

Source_DataDesc

Description of the entity

 

Source_FeatureID

Identifier of the entity used in the  source data.

 

FeatureDetailURL

URL where detailed event entity data can be found

 

FMeasure

Measure along the reach, in percent from downstream end, where a linear event begins (from).

 

TMeasure

Measure along the reach, in percent from downstream end, where a linear event ends (to).

 

EventType

Type of  feature referenced as an event.

 

EventOffset

Distance from the network to be used to display event

Negative offsets display the event to the left of the network and positive offsets display the event to the right of the line.   Offsets are useful for displaying overlapping events.