U.S. Department of the InteriorU.S. Geological Survey

NWIS, STORET, and XML

Advisory Committee on Water InformationSeptember 10, 2003

Kenneth J. Lanfear, USGS

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Purpose

Describe progress in providing an integrated view of NWIS and STORET data

Show preliminary ideas for turning ACWI ACWI Water Quality Data ElementsWater Quality Data Elements into a practical XML Schema for describing sampling stations

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NWIS and STORET

USGS and EPA signed an agreement on Management of Water Quality Data on January 13, 2003. Key elements include:Geospatial internet-based query tool Joint teams of technical staff to outline

options and identify tasksReferences ACWI Data Elements

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Geospatial query tool

STORET(national)

STORETWarehouse

NWIS NWISWeb

LocalSTORET

Transactional Distribution Query Tool

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Phases of development become more challengingPhase Common data in portal Mapping interface How users get full data

sets for stations

1 Station name/number; lat/lon

One-time prototype transfer of locations to geospatial query tool

Table of links to STORET and NWISWeb

2 Location (watershed, state, county); agency; general site type (surface-water, well, lake, etc.)

Regular updates provided to geospatial query tool

Station-by-station links to STORET and NWISWeb

3 Summary info. on constituent groups and sampling frequency

" "

4 Links to all data, allowing detailed selections

Standards-based web mapping services support many interfaces

Portal acts as intermediary to deliver data in single format

5 " Standards-based web feature services allow interfaces to manipulate data display

Delivered in a standard XML schema for water-quality data

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Why do we need an XML Schema?

Any advanced “Water Portal” concept (index, warehouse, distributed database, web service, etc.) works a lot better with a standard way to transfer data

Designing an XML schema enforces a discipline on the data modelACWI Data Elements is a good startThe devil is in the details!

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A (very) DRAFTDRAFT XML schema for water-quality data: station description

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Cautions!!!

We need to determine the scope of the data elements. Which ones actually will be needed in a data repository?

Elements must be matched to missions and goals. Most data systems probably will use a subset of the schema.

Need critical review by experts in XML Schema.

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Some design principles Strictly define critical elements on which we

commonly perform searches, such as lat/lon; station identification; standard station type.

Allow more flexibility on documentation elements (e.g. method of altitude determination). Allow documentation by citation Individual databases can redefine by restriction.

Shamelessly steal ideas from other sources!

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Standards and Recommendations

ACWI Data Elements (Draft) Federal XML Developers Guide

XML Schema style

EPA Environmental Data Registry Data element names

OpenGIS® Geography Markup Language Describe geographic features

ISO 8601 Date, time

HR-XML Consortium Names and addresses

They don’t all agree!

1111

Name and address elements are defined by HR-XML Consortium

No need to invent our own!

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Authority: A Reference

Defines code sets, names, methods, or explanations

Allows great flexibility in documentation

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Station – where you sample

New!

Simple, standard types (5-6?) plus user-defined

types

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Station Location

New

Link to GML for subfeatures

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Pacific Northwest Water Quality Data Exchange (AK, ID, OR, WA)

Data exchange templates and directory services approach

XML Schema in developmentOpportunities to share ideas

NWIS/STORET Portal is similar, but would provide more details about stations

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Extension of Schema

Tie results of sampling to station or sub-features of a station6.0 Sample Collection7.0 Sample AnalysisField trip information?

Where does “3.0 Reason for Sampling” fit?Why did we select this station?Why did we collect this sample?

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Next Steps for XML Schema

Refine schema with expert help, compare to Pacific Northwest schema

Determine role of schema in a water portalScope of data elements – which are needed

and which can we defer?

Test with data output from NWIS and STORET