U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Conflation Lessons In Iowa Using the NHDGeoConflationTool Tim Hines U.S. Department of the Interior U.S. Geological Survey National Geospatial Technical Operations Center

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey History Iowa has LiDAR derived DEMs for most of the state Iowa has LiDAR derived DEMs for most of the state Iowa has created Local Resolution NHD and are using the NHDGeoConflationTool to conflate the local data to the 24k NHD Iowa has created Local Resolution NHD and are using the NHDGeoConflationTool to conflate the local data to the 24k NHD Currently completed line work for 27 Subwatersheds Currently completed line work for 27 Subwatersheds Want to submit the revisions/updates to the NHDGeodatabase Want to submit the revisions/updates to the NHDGeodatabase This can be accomplished using the NHDGeoConflationTool This can be accomplished using the NHDGeoConflationTool Presently 2 Subwatersheds have been successfully conflated and 2 datasets have loaded into the NHDGeodatabase High Resolution Presently 2 Subwatersheds have been successfully conflated and 2 datasets have loaded into the NHDGeodatabase High Resolution This is a first using the NHDGeoConflationTool This is a first using the NHDGeoConflationTool

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Properly structured Source and Target Data is crucial to the success of the NHDGeoConflationTool Process Properly structured Source and Target Data is crucial to the success of the NHDGeoConflationTool Process What is required for the NHDGeoConflationTool?

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey What is required for the NHDGeoConflationTool Target Data = “Your Revised Data” In Geodatabase format using Schema Template v1.06 Source Data = Extracted NHD Data Two Data Inputs are required

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey NHDGeoConflationTool requires the typical NHD Geodatabase feature naming convention and associated tables as per Schema v1.06 Target Data can be projected/extracted into a Empty Schema Template using the ArcGIS “Distributed Geodatabase/Extract Data Tool” to create the necessary schema feature classes and tables to start conflation Schema Templates can be downloaded from the NHD Stewardship page “Download NHD Software” link at Target Data Preparation Input Naming Convention

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Target Data Preparation Input Naming Convention Schema 1.06 Feature Class & Table Naming Convention Hydrography: NHDFlowline NHDLine NHDWaterbody NHDArea NHDPoint NHDAreaEventFC NHDLineEventFC NHDPointEventFC Hydrologic Units: Regions Subregions Basin Watershed Subbasin Subwatershed Tables: NHDFCode NHDFeatureToMetadata NHDFlow NHDFlowlineVAA NHDMetadata NHDProcessingParameters NHDReachCode_ComID NHDReachCrossReference NHDSourceCitation NHDStatus NHDVerticalRelationship

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Target Data Preparation 1D and 2D Line work All features must have FCodes as per NHDFCode table

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Target Data Preparation 1D and 2D Line work 1D and 2D Line work should have correct features in correct feature class layers. Correct FCodes are required.

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Tool Sets Used NHDGeoConflationTool NHD Subset by Poly Tool NHD Flowcheck Tool NHDUtilities XMLExtract XML2GDB NHD Tools Toolbox 3 Python Scripts

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Target Data Preparation Line work 1D Flowlines should have Connectivity, Flow Direction, With digitized (Unless you don’t want Flow), and split at Flowline confluences Use the “NHD Flowcheck Tool” to check for Connectivity, Flow Direction, and legitimate Network Ends

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Target Data Preparation Line work 1D NHDFlowline should not have GNIS ID gaps - Use the NHD Tools “Gap or Branched Attribute Check” script to check for this type of error

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Target Data Preparation Line work 1D and 2D 1D and 2D features must register Use the NHD Tools “Find Artificial Paths Out of Area Features” script to check for this type of error Lake/Pond

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Target Data Preparation Line work 1D and 2D And the reverse as well Use the NHD Tools “Extract Improper Stream/River Flowlines” script to check for this type of error Lake/Pond

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey What Features Conflate NHDWaterbody NHDFlowline What Features Do Not Conflate NHDArea NHDLine NHDPoint Target Data Preparation Line work 1D and 2D

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Typical Conflation Situation in Iowa

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey 12 Digit Subwatershed Ex. 1 Total NHD Flowlines = 123 Total Iowa Flowlines = 1014

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey 12 Digit Subwatershed Ex. 2Total NHD Flowlines = 234 Total Iowa Flowlines = 2559

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Questions?

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey Link to Iowa Conflation Process v1.doc Link to Iowa Conflation Process v1.doc

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey You are now ready to start using the NHDGeoConflationTool Run Prep on NHDSource dataset as well