Site Service Frequently Asked Questions

Common questions about the site service

How do I retrieve just real-time sites?

Real-time sites are USGS hydrologic sites that regularly transmit automated measurements and observations. Currently there is no perfect mechanism for retrieving real-time sites. In particular &hasDataTypeCd=rt will not return only real-time sites, since rt is an alias for instantaneous values (iv). The NWIS Mapper uses an approach that shows “active” sites. However, active sites have different meanings depending on whether they serve automated (time-series) data or are regularly visited by humans for collecting data manually (discrete data). For real-time sites, users are usually interested in automated record stations. Thus combining this with a list of “active” sites that have been operational over a recent time period helps flag those sites that recorded traffic recently. This is close to being a list of current real-time sites. For example, to retrieve all active sites for Rhode Island in a Google Maps format that have recorded observations in the last week, use: .

Is this service available as a Web Feature service?

Not in the format, but The USGS will be rolling out a number of new services to provide monitoring location metadata in the coming months and years.

How do I integrate your site service with commercial mapping services, like Google Maps?

For other mapping services, consult their application programming interfaces (APIs). Most mapping applications can map geographic data in a Keyhole Markup Language (KML) format. Using &format=ge for Google Earth and &format=gm for Google Maps will probably work with Yahoo, Microsoft and other public mapping services because they are KML-friendly.

What is a period of record?*

This is the time period that the site was actively maintained and used. Ideally, it is a period of contiguous time to the present, but sites may be discontinued for a while due to lack of funding or are seasonally affected by the weather. Note that sites where discrete (manual) measurements were made are not “active” in the traditional sense, unless automated equipment is collocated at the site. However they do represent dates when data was collected at the site. A site’s period of record may be further refined to show periods of record for different data types, for example a time range for collecting daily values and discrete water quality measurements.

How do I use the service to determine a list of sites that were removed?

Data collected at a site is always maintained as a matter of record. Sometimes a site is removed from public display. Unfortunately, there is no way to get a list of these sites from the service other than to keep your own copy and compare changes. Note that the modifiedSince argument effectively only shows new sites and sites where site information has changed.

What new features are planned for the site service?

Aside from the web feature service, which is likely to be a separate service, the following improvements are anticipated: Excel 2007 output, search by site name, polygons of enclosed sites, and minimum bounding rectangles. These features are expected in 2014 or 2015.