Analytics

Esri Visualizes NOAA's National Water Model

For the first time ever, you can visualize NOAA’s stream-flow forecasts throughout the continental U.S. in ArcGIS Online, ArcGIS for Desktop or freely via the REST endpoint. By accessing the National Water Model map services, hosted on Esri’s livefeeds2.arcgis.com server, you see the current state of our nation’s surface water network in addition to flow forecasts. Based upon a seamless National Hydrography Dataset and fed by NOAA’s National Weather Service forecast data, the National Water Model forecasts the flow of water along the 2.7 million stream segments in the U.S., aiding environmental resource managers and emergency managers alike. Esri’s map services are updated hourly, and forecasts can be viewed interactively in a time slider or played as an animation, providing an exciting view of how rainfall infiltrates the surface water network, and where it ultimately flows over time.

National Water Model (10-day Anomaly Forecast)

You can find the map services in The Living Atlas of the World in ArcGIS Online, or by connecting to the livefeeds2.arcgis.com server. There are 4 available services, all of which were designed for fast visualization.

National Water Model (Hourly Anomaly Forecast) Contains 15 one-hour forecast intervals visualized by flowrate and anomaly compared to normal monthly flow values. Over 40 million data rows…

National Water Model (Hourly Forecast) Contains 15 one-hour forecast intervals visualized by flowrate. Over 40 million data rows…

National Water Model (10 Day Anomaly Forecast) Contains 80 three-hour forecast intervals visualized by flowrate and anomaly compared to normal monthly flow values. Over 215 million data rows…

National Water Model (10 Day Forecast) Contains 80 three-hour forecast intervals visualized by flowrate. Over 215 million rows…

The key to quickly rendering this amount of content is each service is constructed using several layers. The bottom layer stores the raw base data in an Relational Database Management System (RDBMS), which is used primarily for unique feature identification and large scale display. For small scale display, the base data is dissolved by the Watershed Boundary Dataset Hydrologic Unit 4 Watershed ID, Stream Order level, Flowrate Classification, Anomaly Classification, and Forecast Timestamp. The dissolved data contains a relatively small number of multi-part features that can be drawn quickly regardless of the geographic region being viewed, and is stored in a local File Geodatabase. The final piece is a custom Server Object Interceptor (SOI) on the ArcGIS Server. The SOI traps incoming client requests to control the Layer visibility, Symbology, Identification, and Time Series thresholds for each service. Feature identification is limited to a single feature having the largest Stream Order value where you click.

These services are currently in BETA. Improvements to the services, such as back-office processing changes to speed up data refresh and improvements to scalability are planned for November, 2016.

By the end of 2016, Esri will release an open-source toolkit with documentation explaining the processing required to produce the map services. These tools will walk you through the automated process of downloading provider updates, generating the output datasets, and updating the service content.

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