Nationwide Surface Transportation Weather Observing System

1
Commonality Of Metadata For Environmental Sensor
Stations
Clarus Initiative 4th Annual Initiative
Coordinating Committee Meeting August 8,
2006 Pat Kennedy ITS Specialist, Road Weather
Management FHWA, Washington, D.C.
2
What is Metadata?

• Metadata is defined as data about data
• Metadata is a necessary component for
  observations to be accepted in data collecting
  networks (such as Clarus)
• Metadata can assist in determining if the data
  collected are representative and appropriate for
  widespread use or are only of local significance

3
Benefit to the Community

• Many public and private communities (such as
  weather, energy, commercial vehicle operators,
  agriculture, emergency management) can use ESS
  metadata to determine if the observations
• are representative for their task
• have appropriate exposure
• have a robust maintenance policy
• have an established climate record

4
What is Metadata used for?

• Metadata can be used to describe almost any
  quality about an observation. Some examples
  include
• Platform location elevation
• The types makes of sensors
• Calibration records
• Maintenance history
• Site exposure (terrain, obscurations, vegetation,
  proximity to structures or roads)

5
So, Why Strive for Commonality?

• Current lack of nationally accepted metadata
  model
• Corresponding lack of consistency
• Resulting in a limited usefulness of existing ESS
  data

The FHWAs Road Weather Management Team believes
that all three of these items are significant
shortfalls that need to be addressed by striving
for commonality of ESS metadata.
6
Environmental Sensor Station (ESS) Sites Across
America
7
Metadata Comparisons

• Eight examples of established metadata sets were
  used to compare fields associated with ESS
  surface observations. These included
• Utah DOT
• Meridian
• Washington State DOT
• ESS Siting Guidelines

• Alaska DOT PF
• CMML 2.0
• Clarus
• World Meteorological Organization (WMO)

8
Metadata Characteristics

• This comparison identified at least 105 distinct
  fields that described eight general categories of
  metadata elements including
• ESS platform identification and location
• Site ownership
• Instrumentation
• Video/Camera information
• Communications
• Site layout
• Maintenance

FHWA Road Weather Management
9
Ranking Metadata

• Only four metadata fields were common among the
  eight data sets that were compared
• Platform ID/Site Number
• Plain Text Location Description
• Latitude/Longitude Position (of tower base)
• Site Elevation (of tower base)

10
Metadata Ranking 2nd Level

• Metadata fields that were common among 6 of the 8
  data sets included
• Highway Milepost Marker
• Thermometer Model
• Anemometer Model
• Site Representativeness
• Description of Obstructions
• Landscape Features (terrain)

Hardware Location Attributes
Physical Features Describing the Surroundings
11
Metadata Ranking 3rd Level

• Metadata fields that were common among 5 of the 8
  (gt50) data sets included
• City/County Name
• RPU Make
• Rain Gauge Model
• Barometer Model
• Road Sensor Model
• Sub-grade Probe Model
• Number of Road Sensors

• Units of Measure
• Sensor Manufacturer
• Text Comments for Sensors
• Obs Collection Frequency
• Text Description of Site
• ESS Base Height wrt Road
• Lane Position of Sensor

12
Food For Thought

• You have been provided two spreadsheets
  describing the comparison of eight existing
  metadata sets by category and ranking.
• You have also been provided two other
  spreadsheets
• One of which includes a list of metadata elements
  that are being proposed as a common set of
  standard metadata elements
• And another one that includes comments that have
  been made on this proposed list

13
Comments And Recommendations

• As we get ready to enter into our discussion on
  metadata, please try to think big picture, as
  in nationwide
• Is the proposed list of elements a viable
  template for all states to use as a standard set
  of common elements?
• Please join in this discussion and offer us your
  comments and recommendations!

14
Contact Information

• For information, contact
• Pat Kennedy, FHWA HQ
• Pat.Kennedy_at_dot.gov, 202-366-9498
• Road Weather Management Team Leader
• Paul Pisano, FHWA HQ
• Paul.Pisano_at_dot.gov, 202-366-1301
• FHWA RWM Web Page
• www.fhwa.dot.gov/weather/