Transcript AIP6_WaterSBA_Summary_Recommendations_v3

GEOSS Water Services for
Data and Maps
Community Recommendations
David K. Arctur, Project Lead, GEOSS AIP-6 Water SBA
[email protected]
University of Texas at Austin
Open Geospatial Consortium (OGC)
Presented at GEO X Plenary & Ministerial Summit
Geneva, Switzerland
January 2014
Purpose
In conducting AIP-6 Water SBA, we wished to
identify the “best practices”, exchange
standards, and other conventions needed for
national and regional water agencies to
effectively federate their data services.
This is a story about millions of small datasets:
each with a time series of a variable at a point location
Water Quantity
Rainfall
… continuing and extending
work demonstrated at the
GEO IX Plenary in Brazil, 2012
Step 1: Search for a specific web map of stream gauges
Step 3: Follow the link to the web map
Step 2: Examine the GEOSS registry metadata for the web map
Water Data Maps: Global Stream Gauges
Not just seeing data providers’ bounding boxes, but actual locations
of specific data… (Esri ArcGIS Online web map viewer)
Click to add layers
1.
2.
3.
4.
5.
6.
WMO GRDC (gauge descriptions only, no water data)
Kisters GRDC (WaterML 2 data for OGC Surface Water IE)
USGS NWIS (most have real-time data)
Mexico (some with historical data, hosted by Univ of Texas)
Dominican Republic (historical data hosted by BYU)
Italy & New Zealand (real-time data, developed for AIP-6)
http://bit.ly/19fUSPY
For quick overview
Gauge description
and data links…
For easy analysis
WaterML for full details
WaterML 2.0
Document metadata
Observation description
- Phenomena time
- Result time
- Procedure
- Observed property
- Feature of interest
- Result
- Time series metadata
- Time series data
Time series data, cont’d
Recommendation 1: Use OGC WaterML 2
• Federation of regional & national water data is much easier with
community adoption and support for data exchange standards &
practices
• WMO and OGC are developing international standards for hydrologic
information: WaterML 2 is the preferred encoding
– Part 1: Time series (OGC adopted; WMO pending)
– Part 2: Ratings, gaugings and cross-sections (for determining
flow volume as function of stream depth and streambed
conditions; in development)
– TBD: Sampled observations; Forecast-time representations
Recommendation 2:
Use OGC WFS for feature layer of water data sites
GEOSS
Search
One WFS service per
data layer and/or
producer
WFS
GRDC gauges
(Kisters host)
WFS
Web Map
Viewer
Italy gauges
(ISPRA host)
WFS
New Zealand gauges
(HRC Hilltop host)
Mapping this feature
layer enables direct
visualization of the data
to support interaction
with it.
Recommendation 3: Water Map Service Guidelines
There needs to be a consistent way of describing water data time series, that
would be followed by data producers and software developers.
With this project we are defining a core set of feature attributes which characterize
time series:
•
•
•
– WaterMLURL for a REST call to a data service endpoint, that enables a time series
to be queried from this location.
– GraphURL and DownloadURL for graphing or downloading the data, if available.
– BeginDate of the data (the time of first information, using ISO 8601 time format).
– EndDate of the data (make Null if this is current time).
– Descriptor – text descriptor of this feature (e.g. Site name for gaging station, COMID
for NHDPlus, etc)
– Source – text field that specifies the source of the data e.g. USGS, etc.
If the EndDate field is empty (null), this means the data service is a near-real-time
feed, not just an historical dataset.
The WaterML time series data is served by OGC Sensor Observation Service (SOS).
WMO/OGC Hydrology Working Group is working on unambiguous conventions for
data service REST calls – keep track of this
Recommendation 4:
Use OGC SOS 2 as the web data service for WaterML 2
But be prepared for the many sites
running CUAHSI WaterOneFlow (WOF)
web service for WaterML 1.x data
Web Map
Viewer
SOS
GRDC WaterML2
(Kisters host)
WOF
Italy WaterML1.1
(ISPRA host)
SOS
New Zealand
WaterML2
(HRC Hilltop host)
Summary of web
services
6
Return time series
data or graph
(WaterML, CSV)
Community
Web Portal
Discovery, Access
and Visualization
1
Request data about
[observed property]
2
Return list of Data
Providers’ map layers
(CSW)
Catalog of
Data Providers’
gauge layers
5
Request data service
for time series of
selected gauge
(SOS)
Data service
for time series
at one gauge
4
Return gauge locations as a
map layer (GML SF)
3
Request map from each
Data Provider about
[observed property]
(WFS)
Map of gauges (one layer
per observed property) for
one Data Provider
Recommendation 5: Data providers should manage
WFS time series descriptions in a catalog registry
• Each data provider could install and manage a catalog registry
of relevant time series descriptions (WFS feature layers)
OR…
• Use an established community catalog for that purpose
(eg, CUAHSI HydroServer)
• This catalog should itself be registered with GEOSS.
Example: Canadian Monitoring Network
•
This data provider has registered its Kisters
precipitation feeds in a GIcat registry installed by the
data provider.
•
This GIcat service’s CSW interface is registered in
GEOSS.
•
This enables distributed search for a single known
monitor site via GEOSS Portal…
Public Web Map Viewer (registered in GEOSS)
for Global Precipitation Gauges
http://bit.ly/19fV1Tz
Water Data Maps: Canada Precipitation Gauges
Water Data Maps: Canada Precipitation Data
Register with GEOSS to promote
interdisciplinary discovery
www.geoportal.org
GEOSS
By registering the
community portal
and its catalog in
GEOSS,
interdisciplinary
users can more
easily discover
these resources
Community
Web Portal
Discovery, Access
and Visualization
(SOS)
Data service
for time series
at one gauge
(CSW)
Catalog of
(WFS)
Data Providers’ Map of gauges (one layer
gauge layers per observed property) for
one Data Provider
Summary of Recommendations
1. Use OGC WaterML 2 for water-variable time series data
(streamflow, precipitation, runoff, etc).
2. Use OGC WFS for a feature layer of water data sites; one WFS
service per data layer / producer.
3. Use consistent & minimal subset of time series description fields
in the WFS data service.
4. Use OGC SOS 2 as the web data service for WaterML 2, but be
prepared for the many sites running CUAHSI WaterOneFlow
(WOF) web service for WaterML 1.x data, and even WFS for
WaterML time series data.
5. Each data provider could install and manage a catalog registry of
relevant time series descriptions (WFS feature layers), or use an
established community catalog for that purpose (eg, CUAHSI HIS
Central). This catalog should itself be registered in GEOSS.
Future Work: AIP-7
End-user focus
• Develop more application-oriented scenarios around flood, drought, and
water quality monitoring and prediction.
Technological focus
• Support discovery and access through GEOSS to additional water resource
variables, such as stream depth, precipitation, water quality, soil moisture,
evapotranspiration, total water storage.
• Promote international conventions for the specific data exchange requests
(i.e., allowed parameters and values) between clients & data servers.
• Provide cloud-based data services to reduce equipment, software, and
training needs for developing countries.
Institutional focus
• Coordinate with IGWCO and WMO so this development work will become
institutionalized by the appropriate international authoritative agencies.
• Work with developing countries to improve readiness to share national data
Thank you!
David K. Arctur
[email protected]
University of Texas at Austin
Open Geospatial Consortium (OGC)