NHD Tools

The following tools are provided to assist in the use of NHD data. Any problems encountered when using these tools should be reported to nhd@usgs.gov.

• NHD GeoConflation Tool
  The GeoConflation Tool is one of several methods available to update the National Hydrography Dataset (NHD). The tool automates the NHD Create Process used to generate the high resolution (24K) NHD data from the medium resolution (100K) data. NHD conflation is the integration of two datasets into one. The basic goal of conflation is to conserve ReachCodes and ComID’s by duplicating them from the original dataset to the modified or target dataset whenever possible. This allows the history of the ReachCodes, and by association any information tied to the ReachCode, to be preserved.
  
• USFS Reprojection Tool Version 2.0 - The USFS Reprojection Toolbar changes geographic projection and can transform datums using all available ESRI ArcObjects algorithms. It was developed by the USDA-Forest Service for the National Hydrography Dataset (NHD) NHDinGEO format, but can function on any personal or file geodatabase. This is an add-on toolbar written for ESRI's ArcGIS 9.2, 9.3, and 10. The advantage is that it reprojects whole personal and file geodatabases at once, and updates the metadata at both the Geodatabase, Dataset, and Feature class levels in both the Data Quality and Spatial Reference sections of standard FGDC metadata--or creates its own metadata if there is none. Version 2.0 works on ArcGIS 9.2 while version 2.1 works on ArcGIS 9.3, 2.2 works on ArcGIS 10.
  
• Hydrography Event Management Tool - The Hydrography Event Management (HEM) Tool provides full functionality for adding and editing events in the NHD. Events are informational data that are linked to the NHD using a linear referencing system on NHDFlowlines. The use of events is a key characteristic of the NHD by allowing vast amounts of scientific information to be linked to the NHD while keeping the design simple and by making advanced analysis techniques possible. The HEM tool handles all the linear referencing mechanics to make working with events easy. It works on point, line, and area events and allows events to be located interactively, imported, or calculated. An I.D. value is created that provides the link between the event location and the informational data tied to the location. It also creates metadata linked to the event. The tool also provides network measuring to determine distances through the flowline network. The HEM tool was developed by the Department of the Interior - Bureau of Land Management.
  
• NHD Network Builder - After reprojecting NHDinGEO data, it is necessary to re-build the network(s) to restore flow and directionality to your network data. Network_PGDB_S0_FL.exe is a tool that rebuilds a network and sets the flow direction within the context of the geometric network based on the flowdir attribute. The tool does not rebuild or update the NHDFlow table.
  
• Geographic Names Information System (GNIS) - Access GNIS to check, submit new, or make changes to names in GNIS.
  

Disclaimers:

• Non-endorsement of Commercial and Other Non-USGS Products and Services
  
• USGS Public-Domain Software

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NHD Conflation Tool

The GeoConflation Tool is one of several methods available to update the National Hydrography Dataset (NHD). The tool automates the NHD Create Process used to generate the high resolution (24K) NHD data from the medium resolution (100K) data. NHD conflation is the integration of two datasets into one. The basic goal of conflation is to conserve ReachCodes and ComID’s by duplicating them from the original dataset to the modified or target dataset whenever possible. This allows the history of the ReachCodes, and by association any information tied to the ReachCode, to be preserved.

One way to think of the process is "change detection". There are two inputs to the tool: the original NHD subbasin and the newly created or updated geometry called the target subbasin. The source NHD subbasin is then compared to the target subbasin. Where the geometries of flowlines and/or waterbodies match within specified tolerances, ReachCodes and ComIDs are automatically transferred from the source NHD to the target dataset. Close matches are flagged for closer review by the user to determine if there is an actual match or not. If the feature exists in the original, but not in the target, a “delete feature” is automatically generated. In the alternative circumstance where the feature exists in the target but not the source, a new ReachCode and ComID is applied to the feature and a “create new feature” is automatically generated.

As in any update process the results are only as good as the input data. The updates or target data must have FTypes, FCodes, connectivity, and be in correct the NHD schema. In addition, the target data must pass all QA/QC checks required before any data is integrated into the NHD. The end result of the conflation process is a “new” dataset consisting of the new geometry complete with ReachCodes and ComIDs. All changes have been tracked. The updates are then uploaded to the database. In the near future, the new PermID and Crosswalk tables will be incorporated into the tool.

For more information, visit http://webhosts.cr.usgs.gov/steward/.

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USFS Reprojection Tool Version 2

The USFS Reprojection Toolbar changes geographic projection and can transform datums using all available ESRI ArcObjects algorithms. It was developed by the USDA-Forest Service for the National Hydrography Dataset (NHD) NHDinGEO format, but can function on any personal or file geodatabase. This is an add-on toolbar written for ESRI's ArcGIS 9.2, 9.3, and 10. The advantage is that it reprojects whole personal and file geodatabases at once, and updates the metadata at both the Geodatabase, Dataset, and Feature class levels in both the Data Quality and Spatial Reference sections of standard FGDC metadata--or creates its own metadata if there is none. Version 2.0 works on ArcGIS 9.2 while version 2.1 works on ArcGIS 9.3, 2.2 works on ArcGIS 10.

Developer: U.S. Forest Service - Natural Resource Information System

Software Environment: ArcGIS 9.2, 9.3, 10

Purpose: The USFS Reprojection Toolbar changes geographic projection and can transform datum using all available ESRI ArcObjects model algorithms. This is an add-on toolbar written for ESRI's ArcGIS 9.2, 9.3 and 10. Once a geodatabase is highlighted and the toolbar's button is pushed, a user interface appears. User must name a new output personal geodatabase, and select the desired projection and datum. A progress report at the lower left corner of ArcCatalog shows current status at all times during processing. FGDC compliant metadata is updated in both the Data Quality Information and the Spatial Reference Information sections. To reproject, the NHD network must be deleted first and then rebuilt after the reprojection is complete. The "NHD Network Builder" can be downloaded at: http://nhd.usgs.gov/tools.html.

Loading and Installing:

Get the appropriate version at ftp://ftp2.fs.fed.us/incoming/wo/nris/water_abat/Reprojection_Tool_v2/

1. Close ArcCatalog if it is currently running.
2. Double-click on the .msi file (or the .esriAddIn file) and it will set itself up.
3. The full help documentation/discussion is in the toolbar and may be saved as a Microsoft .rtf file.

For more information on ESRI AddIns http://blogs.esri.com/Dev/blogs/arcgisdesktop/archive/2010/05/05/Add_2D00_ins-for-ArcGIS-Desktop-10.aspx

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Hydrography Event Management Tool

The Hydrography Event Management (HEM) Tool provides full functionality for adding and editing events in the NHD. Events are informational data that are linked to the NHD using a linear referencing system on NHDFlowlines. The use of events is a key characteristic of the NHD by allowing vast amounts of scientific information to be linked to the NHD while keeping the design simple and by making advanced analysis techniques possible. The HEM tool handles all the linear referencing mechanics to make working with events easy. It works on point, line, and area events and allows events to be located interactively, imported, or calculated. A Source Feature ID is created that provides the link between the event location and the informational data tied to the location. It also creates metadata linked to the event. The tool also provides network measuring to determine distances through the flowline network. Currently, two versions of the tool are available: 2.3 for ArcGIS 9.3 and 2.5 for ArcGIS 10.

Developer: Department of the Interior - Bureau of Land Management

Software Environment: ArcGIS 9.3 or 10

Tool Download/Training Materials

HEM Tools Support

HEM Training Request/Registration

HEM EPA Add-on Tools

The U.S. Environmental Protection Agency (EPA) has developed a supplemental set of indexing functions for the HEM, which are available through the HEM EPA Add‐Ons toolbar. This toolbar allows users to create, edit and manage custom point, line and area events. The toolbar also includes functionality that was previously a part of the PC based Reach Indexing Tool (PC-RIT), such as Find Overlapping Waterbodies, Extract from EPA Program Events, and a post processing tool to aid in preparing events for submission to the EPA's Reach Address Database (RAD). For a complete list of HEM EPA Add-on tools please download the HEM EPA Add-On Tools brochure.

Developer: RTI International (contractor to EPA)

Software Environment: ArcGIS 9.3

EPA Add-On Tools Download

EPA Add-On Tools Support

EPA Add-On Tools Training Materials

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NHD Network Builder

Software Environment: NHD Network Builder runs under ArcGIS 9.3x

Purpose: The NHD Network Builder builds a personal geodatabase (mdb) or File geodatabase (gdb) network and sets the flow direction as per the 'Flowdir' field of the 'NHDFlowline' feature class.

Important Details: This application is only intended to rebuild the network on NHDinGEO data that has already been prepared for networking. It is normally used when rebuilding a network after the NHDinGEO has been projected.

Downloading and Installing: To download NHD Network Builder, click on the link below using your right mouse button and choose 'Save Link As...' or 'Save Target As...' (depending on your browser). This allows you to save the file on your PC's hard drive.

• Network Builder 64-bit
• Network Builder

To install NHD Network Builder on a PC: Copy the executable to your hard drive. This need not be the directory containing the NHDinGEO data. The full help documentation/discussion is in the toolbar and may be saved as a Microsoft .rtf file.

Using NHD Network Builder: Once you have installed the software, it can be used to rebuild the geometric network for NHD data. Go to start – All programs - . Browse to the file ex: C:\Yellowstone\Yellowstone.mdb. Click on the Build Network button. A second window will appear indicating when the network is built.