Data Construction

The Montana Hydrography framework data is a statewide subset of the USGS National Hydrography Database (NHD). The theme lead works with the USGS and its protocols to both assist with maintaining the national dataset and to offer the best available Montana hydrography data to parties interested in the state’s waters. The Theme Lead (or designate):

1. Obtains the most recent/up-to-date copy of the Montana extent of the NHD from the USGS and publishes it in Montana State Plane to the Montana Data List for data download and in a web map service.

2. Either:

  • Selects a basin that is targeted for annual systematic NHD improvements

3. “Checks out” one (or more) Montana subbasin extent of data (geometry and attributes) from the USGS NHD.

4. Edits the data using USGS NHD editing tools (NHD Update Toolbar).  Edits are made based on Montana hydrography subject matter expert knowledge, orthoimagery, and other related water datasets.  Editing efforts primarily focus on improving spatial alignment/quality and fixing problems reported via Montana Hydrography Edit Request Viewer.

5. Submits the updated/corrected USGS NHD data back to the USGS following their quality control process. The edited data is later included in the next USGS release of the statewide NHD (approximately every 2 to 3 months).

6. Repeat Steps 2 through 6 systematically—this process is ongoing and does not have a completion date. See the Enhancements Table below (“USGS NHD Data Quality Improvements” entry).

There are approximately 1.25 FTE working to steward MSDI Hydrography framework data, including edit and update the USGS NHD data, refresh the published copies of Montana’s extent of the data in the Montana Data List, and train others on the use of the data. Occasionally, skilled technologists with GIS experience and Montana water expertise, or substewards, are trained in how to edit the USGS NHD (steps 2-4 above), assisting the process of updating, correcting, and maintaining the USGS database.