Tag Archives: National Hydrography Dataset
by Cynthia Deischer and Ray Postolovski
Juliet: “What’s in a name? That which we call a rose by any other name would smell as sweet.”
Romeo and Juliet meet in Shakespeare’s tale. They are predestined from the start because of their surnames. Juliet tells Romeo that a name is an artificial and meaningless convention. Meaning what matters is what something is, not what it is called. However in the geospatial community, a name is far from meaningless and what something is named is just as important as what something is. Continue reading
by Tommy Dewald, USEPA Office of Water The National Hydrography Dataset Plus (NHDPlus) is a suite of geospatial products that build upon and extend the capabilities of the NHD (1:100,000 scale) by integrating it with the National Elevation Dataset (30M) … Continue reading
by Ariel T. Doumbouya, NHD Team, United States Geological Survey
Fish sampling sites in the Nashua River Subbasin in Massachusetts are linked to the National Hydrography Dataset (NHD) as events using the Hydrography Event Management (HEM) Tools. Events allow scientific information to be linked to the NHD which provides a powerful modeling framework that can be used to locate water related information on the network, establish up and/or downstream relationships, perform habitat and species modeling, and determine relationships between other environmental factors.
by Kathy Isham, National Hydrography Dataset, USGS The US Geological Survey (USGS) has redesigned its applications page for the National Hydrography Dataset (NHD). The new applications page is organized into the six different types of applications that highlight how USGS … Continue reading
What it does: The Esri Hydro Viewer presents information about watersheds, including spatial information about contributing watershed area. For example, if you click on a watershed in Texas, the application presents a detailed report of information about the selected watershed, and highlights the larger hydrologic unit that it is contained within. The report tells you what category of watershed you have selected, and gives the names of the larger contributing units, as well as the HUC number, area, mean annual flow, cumulative drainage, and a brief description of the watershed. The application presents information about the watershed and helps you visualize how your selected watershed fits into the larger national context.
Esri Hydro Viewer with Subbasin Austin-Oyster in Texas selected.
The application also has navigational functionality that makes it easy for you to zoom between region, subregion, and subbasin scale levels, illustrating to map readers the multi-scaled nature of the data, and making those relationships easy to understand—especially to someone who is does not know much about hydrology.
Zoomed to Subregion level, Galveston Bay – San Jacinto.
Even though the base map you see is our Hydro Basemap, we use Bing Maps for our search functionality. To do this, you need to hide the Bing Maps layer so the geocoding works, but the layer does not appear. Using Bing Maps requires a Bing Maps application “key,” which is packaged together with ArcGIS Server 10.0. You can obtain this by going into Server Manager – Settings – and Bing Maps Key. Further instructions on using Bing Maps can be found here.
Whenever you click on the map, two queries are executed (unless you are at the Regional scale level) – one for the selected unit, and one for the larger unit that it is contained within. It looks like the second query is done using a spatial relationship, but we actually used a “query.where” to query for the unit with the same name as the selected unit. By querying based on attributes, our queries run much faster.
The charts in the reports were generated using Google Charts, which makes it very easy to create nice looking visual aids. As you can see in the figure below, not much code is required to build the charts. We used pie charts to represent our data, but there are many other different types of charts available for use as well.
Three different report templates are specified in the code – one for the Region level, one for the Subregion level and one for the Subbasin level. The formatting is mostly done using plain HTML so it would be easier to modify the reports.
The Esri Hydro Viewer can be customized for other data or purposes. For questions or assistance with this please contact Mapping Center.
Special thanks to Kenny Ling for providing this post. Questions for Kenny: Kling@esri.com.
The Hydrography Event Management (HEM) Tool Version 2.4 for ArcGIS 10 is now available!
The HEM Tool provides full functionality for adding and editing events in the National Hydrography Dataset (NHD).
Events are informational data linked to the NHD using a linear
referencing system on NHDFlowlines. The use of events allows vast
amounts of scientific information to be linked to the NHD.
The HEM tool handles all 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 number of state and federal partners have adopted HEM: Environmental Protection Agency (EPA) incorporated HEM to meet Clean Water Act reporting requirements, the U.S. Forest Service incorporated HEM functionality into their National Resource Information System (NRIS) Aquatic Surveys application, Bureau of Land Management (BLM) incorporated HEM to support event creation for its Oregon/Washington Aquatic Resource Information Management System
and is evaluating its use for a national Riparian Database, and the HEM
Tool is used to georeference water quality data to the NHD, and this
information is then used for Section 303(d) water quality reports on impaired waters.
HEM effort is a unique collaboration between the BLM, U.S. Geological
Survey (USGS), and the EPA that results in ongoing tool development and
support to the expanding HEM user community.
The USGS provides basic to advanced HEM training with easy to follow exercises:
and additional user support in the Troubleshooting Guide.
To find out more information visit USGS’s HEM site.
Special thanks to Ariel Bates for providing the post. Questions for Ariel: firstname.lastname@example.org