More than you probably wanted to know about NWIS and NWISWeb U.S. Department of the Interior, U.S....
-
Upload
nicholas-mason -
Category
Documents
-
view
212 -
download
0
Transcript of More than you probably wanted to know about NWIS and NWISWeb U.S. Department of the Interior, U.S....
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