Indiana National Hydrography Dataset (NHD) Improvement and Application Workshop NHD Local-Resolution...

Indiana National Hydrography Dataset (NHD) Improvement and Application Workshop

NHD Local-Resolution Development

Coordination of Indiana GIS through dissemination of data and data products, education and outreach, adoption of standards, and building partnerships

Agenda

• Background Pilot Study

• Approach• Project Tasks

Conversion Conflation

• Demo• Status / Next

Steps


Background

• Working closely with IGIC Waters Workgroup to develop Local-Resolution NHD for the State of Indiana Product must meet USGS NHD capture

standards Loaded into USGS National Map and

IndianaMap upon QC and approval More detailed hydrography, more

accurate spatial locations All attributes that currently exist in the

1:24K NHD will be transferred (conflated)


Background

Small watershed in Hamilton County (Morse Reservoir and agricultural land)

Broad representation of the water features to be included in the statewide project

Designed to provide a basis for stream location accuracy and upstream drainage area limit assessments No 1:24K NHD attributes conflated

Written report of findings

Pilot study conducted in Summer 2009


Background

Upper Eel will be first sub-basin completed Linework QC and approval

prior to conflation Interim attribute QC before

reach codes are allocated Attribute conflation QC

before work begins on additional sub-basins

Statewide project completed by HUC-8 watershed sub-basin in phases:

37 additional sub-basins in state Local subcontractors will assist with

hydrography


Approach

5 feature classes created NHDFlowline (Stream/River,

Canal/Ditch, Artificial Path) NHDWaterbody (Lake/Pond,

Swamp/Marsh, Reservior) NHDArea (Large

Stream/River, Large Canal/Ditch)

NHDPoint (Gaging Station, Well)

NHDLine (Dams)

• Creation of local-resolution hydrography


Approach

• 6 acre upstream drainage limit• Features digitized from orthoimagery

and elevation data

• 1:24K NHD attribute conflation – NHD attribute population for new features


Approach

• Base Data Imagery

2005 one foot and/or half foot pixel RGB orthophotography

Terrain (Contours, DEMs, Hillshades) 2005 five foot cell size DEM (ISTAR)

Supplemented by newer and/or more accurate local data where available


Approach

• Reference Files Local Hydrography provided by the

State National Wetlands Inventory (NWI) INDNR Dams DOT Bridges 1:24K NHD Karst Dyelines


Project Tasks - Conversion

1. Hydro-correct elevation data Generate 6 acre basins and streams

for reference (guidance for upstream limits and stream location)

Generate contours, DEMs, hillshades for reference



2. Digitize NHD features Create 1:2,400 or 1:1,200 scale hydrography

layer (dependent upon imagery source) to the 6 acre upstream drainage limit

Imagery will be primary source for data conversion, terrain data used where features are not visible

1:24K NHD used as reference to ensure all features from the 1:24K NHD have been incorporated

Hydrography edge-matched to 1:24K NHD along state borders


Project Tasks - Conversion• Business Rules

NHDFlowline If 1:24K flowline extends

further upstream than 6 acres, it will be maintained

If features from 1:24K flowline no longer visible, not included in local resolution dataset

If feature is less than 20 feet wide and less than 600 feet long it will be captured as a flowline



• Business Rules NHDArea

If feature is more than 20 feet wide and more than 600 feet long it will be captured as an area

All 1:24K NHDAreas will be retained if the feature is visible in the imagery



• Business Rules NHDWaterbodies

¼ acre or larger will be collected; if less than that but included in 1:24K NHD and visible in imagery, it will be kept

Generated using ERDAS Objective (Ortho-recognition software)



• Business Rules NHDPoints – no new features added,

copy over and adjust existing 1:24K NHD features as necessary

NHDLines – new features added if found in reference files (dams), will also copy over and adjust existing 1:24K NHD features as necessary



3. Prep data for conflation• The NHDinGeo version 2.0

database schema will be used• Combination of USGS scripts,

and ArcGIS 9.3 tools to check: Topology Flow direction FCode population Artificial paths Connectors


Project Tasks - Conflation

USGS NHD GeoConflation Toolset

Reach codes, GNIS info conflated from 1:24K NHD, and generated for new features using the USGS NHD tools

Intermittent/Perennial designations conflated for1:24K attributes only

4. Conflation of1:24K NHD attributes and data population for new features



Most performed through NHD GeoConflation queues at various stages After permanent reach codes

assigned, checks for gapped or branched reach codes

Checks for gapped or branched GNIS names

Subsequent processing steps cannot proceed until potential problems have been resolved

Quality Control of conflated attributes:

* Close coordination with and approval by USGS



• Waters Workgroup will check out 1:24K NHD sub-basins as conflation occurs to avoid any other edits being made to the sub-basin

• Feature level, FGDC compliant metadata generated for each sub-basin


Demo


Status / Next Steps

• Status Completed conflation training with USGS Base data received for Upper Eel pilot area

• Next Steps Complete conversion and conflation tasks

for Upper Eel pilot area 3 iterations of QC performed by Indiana’s QC

team Prioritize work, outline schedule for

remaining sub-basins Train and engage subcontractors


Questions and Answers

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Indiana National Hydrography Dataset (NHD) Improvement and Application Workshop NHD Local-Resolution...

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