More than you probably More than you probably wanted to know about wanted to know about NWIS and NWISWebNWIS and NWISWeb

U.S. Department of the Interior, U.S. Geological Survey

Kenneth J. Lanfear USGS

Transactional• Data entry

• Quality assurance Access by USGS only 1980’s and updated 48 installations at local

offices Database of record

Large subset of NWIS• Updated only from

NWIS Public access 1995 Organized primarily

around station

NWISWebNWIS

What’s in NWIS but not NWISWeb?

Unit values (except current)• 1 daily value = 96 unit values• Working on providing this.• Older archives are on paper tapes and probably never

will become widely available! Rating curves (measurements available) Local offices can restrict some data

• Quality-assurance issues• Cooperator restrictions

Components of NWISWeb

Real-time Site Inventory Surface Water

• Daily values

• Statistics

• Peak flows

• Field measurements Ground Water

• Levels Water Quality

Selection Choices within NWISWeb

Site location• State, county, hydrologic unit, lat-lon box• NOT: Map … coming soon!• NOT: NHD-id (Reach number)

Site identifier• Name, number, agency code, etc.

Site attribute• Site type, drainage area, well depth, etc.

Data attribute• Update time, period of record• NOT: Data values!

Site Location: The dirty little secret about accuracy

Most sites were established before GPS and GIS.

Location refers to gage house

Reviewed 24,055 locations• 73% automatically matched to

NHD with no problem

• 17% changed gage-house loc. Avg. change = 1,100 m

Est. 1903

LOCATION.--Lat 43° 51'30", long 110° 35'09", in SW1/4 SE1/4 sec.18, T.45 N., R.114 W., Teton County, Grand Teton National Park, Hydrologic Unit 17040101, on left bank 1,000 ft downstream from Jackson Lake Dam, 4.1 mi west of Moran, and at mile 988.7.

Every NWISWeb retrieval is a “cgi GET” request.

The entire request is expressed within a URL.

Can bookmark. You can deduce the

parameters needed to make a different request.

http://nwis.waterdata.usgs.gov/nwis/discharge?site_no=01613000

NWISWeb already has a web service … sort of!

Request stations in a lat/lon box: http://nwis.waterdata.usgs.gov/nwis/inventory?nw_longitude_va=1120100&nw_latitude_va=164500&se_longitude_va=1120000&se_latitude_va=164000&coordinate_format=dms&format=sitefile_output&sitefile_output_format=xml&column_name=agency_cd&column_name=site_no&column_name=dec_lat_va&column_name=dec_long_va&column_name=coord_datum_cd&column_name=alt_va&column_name=alt_datum_cd&column_name=station_type_cd&column_name=rt_bol&column_name=discharge_begin_date&column_name=discharge_end_date&column_name=discharge_count_nu&column_name=peak_begin_date&column_name=peak_end_date&column_name=peak_count_nu&column_name=qw_begin_date&column_name=qw_end_date&column_name=qw_count_nu&column_name=gw_begin_date&column_name=gw_end_date&column_name=gw_count_nu&list_of_search_criteria=lat_long_bounding_box

NWISWeb returns file

User has to know how to construct the URL, unique to NWISWeb.

No schema to explain what the elements mean or how they’re related!

Error handling is non-standard. None of these problems are insurmountable to a

determined user. They just add to the costs of doing business with NWISWeb.

Not really a web service

Retrieving the Site Filein 1-degree blocks

> 20,000 stations in 1-degree block.

Texas restricts many wells which need QA.

XML Schemas precisely define

What information is needed to make a request

What will be returned• By a successful request

• By a failed request

USGS Water Schemas

Need to define “official” XML schemas for describing USGS hydrological data

Schemas need to be carefully thought out• Once widely used they will be difficult to

change Ideally schemas should first be

coordinated with other agencies and groups that publish hydrological information

Example Web Service

Server

Server

NWISWeb

Internet

cuahsi.com Database

cuahsi.comWeb Server

Users sees USGS data on cuahsi.com

Web site

Other cuahsi.comdata sources

How much of NWISWeb is stored by 3rd party and how much retrieved as needed?

Business Value of Web Services

Expands the ways that USGS Water Data can be used by the public.

Makes integrating USGS Water Data into other products much simpler.

Creates new markets for USGS Water Data. Provides a means for the evolutionary

reengineering of NWISWeb.

Bottom line: We see CUAHSI as a distribution channel, not a competitor!

How to move to web services: Current USGS thinking – not a promise!

Part One (FY05): Create Station Web Service Prototype• Completed February 2005• Need to give additional demonstrations to other interested parties

Part Two (Proposed FY06):• Define XML schemas for WRD hydrological data• Elicit and document requirements from internal, government and

external users• Refine “best fit” web services technologies for WRD through further

investigation and prototyping• Internally publish and use some test web services as a learning

experience Part Three (FY07 and beyond)

• Allocate funding• Start a limited “beta” service• Refine technologies and infrastructure for production use• Deploy production web services

Summary

NWISWeb is the public outlet for NWIS.• Accurate transformation of NWIS data

USGS business model supports third-party distribution of NWISWeb data.

USGS is actively studying web services.• Need advice/coordination on schemas

• Implementation depends on funding