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3D Hydrography Program 3DHP_all: HydroLocation

By NGP Standards and Specifications

HydroLocation (hydrolocation) is a point spatial table that represents locations which lie along a flowline.

hydrolocation (spatial table)

hydrolocationfeaturetype (domain)

hydrolocation (spatial table)- Hydro location is a point spatial table that represents locations which lie along a flowline and uses the hydrolocationfeaturetype domain.

Name (Alias) Definition Type Allow Nulls Length Domain Default Values Comments
id3dhp Unique identifier for 3DHP features. Text Yes 7 - -

This is a base-36 7- digit alphanumeric unique identifier that is not persistent. 

Applied to hydrolocation features in this case.
featuredate Date the feature was loaded into the 3DHP core database. Date Yes - - - -
mainstemid

A cross-dataset identifier for all flowlines that represent the headwater

to outlet path of a river.

 Text Yes 200 - -

A mainstem is equivalent to a feature with the same levelpathid in NHDPlus HR.

The text field will be a <geoconnex.us>*.
universalreferenceid Persistent identifier appropriate for the hydrologic location type. Text Yes 200 - - -
gnisid

A permanent, unique number assigned by the Geographic Names

Information System (GNIS)** to a geographic feature name for the sole

purpose of uniquely identifying that name.

 Long Integer Yes - - -

gnisid = "null" if no name is associated with the feature. The gnisid is conflated

from points and assigned to features. The most recent name, and any historic

names, can be retrieved from the GNIS data base using the gnisid.
featuretype Feature type description. Short Integer Yes -

hydro-locationtype

 - -
featuretypelabel The name of the feature type. Text Yes 50 - -

The featuretype label is based on the coded value description in the featuretype field.

Allows label display in non-ESRI datasets.

*More information about geoconnex can be found here: https://waterdata.usgs.gov/blog/nldi-geoconnex/.

**More information about GNISID can be found here: https://www.usgs.gov/tools/geographic-names-information-system-gnis.

hydrolocationfeaturetype (domain)- The hydrolocation spatial table uses the hydrolocationfeaturetype domain to classify the featuretype attribute.

Code Description Definition
1 Catchment Outlet The location where water flows out of a catchment.
2 Confluence The location where two flowpaths converge.
3 Waterbody Outlet The location where water flows out of a waterbody. 
4 Divergence The location where flow splits into two or more downstream flowlines.
5 Terminus The location where a network ends at the ocean or large lake.
6 Headwater The location where a river is thought to begin.
7 Spring A place where water emerges naturally from the ground.
8 Sink The location where a stream enters an underground conduit, terminates in an isolated sink or depression. Represents the low point to which water flows within a closed basin.
9 External Connection The location where a stream enters a non-USGS authoritative source managed by another entity.
10 Reachcode Start The location where a legacy National Hydrography Dataset (NHD) reachcode starts.
11 Reachcode End The location where a legacy National Hydrography Dataset (NHD) reachcode ends.

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