1. Point Observations Information Model
USGS
Data Source
Streamflow gages
Network
Neuse River near Clayton, NC
Sites
Discharge, stage
(Daily or instantaneous)
Variables
Values
206 cfs, 13 August 2006
{Value, Time, Qualifier}
A data source operates an observation network
A network is a set of observation sites
A site is a point location where one or more variables are measured
A variable is a property describing the flow or quality of water
A value is an observation of a variable at a particular time
A qualifier is a symbol that provides additional information about the value

2. Observations Data Model Schema (version 4.0)
Data Source and Network
Controlled Vocabulary Tables
Sites
Variables
Values
Metadata
e.g. mg/kg, cfs
e.g. depth
Streamflow
Depth of snow pack
Landuse, Vegetation
e.g. Non-detect,Estimated,
Windspeed, Precipitation
A data source operates an observation network
A network is a set of observation sites
A site is a point location where one or more variables are measured
A variable is a property describing the flow or quality of water
A value is an observation of a variable at a particular time
Metadata provide information about the context of the observation.
Data Discovery
Data Delivery
Observations Data Model Schema (version 4.0)
Ernest To
Center for Research in Water Resources
University of Texas at Austin