AQ uFIND Architecture

The basis of AQ uFIND records are WMS layers described in GetCapability documents. These xml documents have initial metadata for discovery and the needed metadata for data access. There are standard, required fields in WMS GetCapabilities, but there are is also a significant amount of flexibility in the WMS GetCapabilities to add additional metadata.

DataFed has extended the WMS GetCapabilities of the data layers found in DataFed, by adding 'machine tags' for the facets found in AQ uFIND. DataFed capabilities also include contact information of the distributor and description of the layers. Another defining attribute of DataFed capabilities docs is that they are divided by dataset, so there is a capability for each dataset in DataFed. With the additional information added to DataFed GetCapabilities, an ISO 19115 metadata document could be created for each WMS map layer in the capability.

Alternatively, wild WMSs can be added to the AQuFIND through a human route and a machine route. WMS GetCap links can be submitted to the metadata editor. This editor will automatically extract the metadata available in the WMS capability doc, and then will provide a user interface to pick the layers to be added to AQ uFIND and then add the additional required facets keywords as well as optionally adding additional contact information for the registrant, data originator and dataset description. The output of the metadata editor is a url (API) with key/value pairs needed for the creation of an ISO 19115 document. Alternatively, if a user knowns the url structure they can submit a capability doc + key/value pairs with facets to the ISO Creator Service directly.

The ISO Creator Service takes the WMS GetCapabilities doc + the ISO key/value pairs as one input. The other input is the AQ Community Catalog Metadata Record template. The ISO creator then outputs an ISO 19115 document.

The ISO 19115 doc is passed through an ISO validator that validates the metadata document against the ISO 19115 schema, to ensure syntactically it's correct. The doc is then passed through another validation process against the AQ Community Catalog Metadata Record template, to ensure that the catalog records have all required facets and that every record is up-to-date. If the record is missing a piece of metadata, that record is modified to include a placeholder for that field. Once the records are validated, they are saved into the AQ Community Catalog (WAF). Note: Currently, there is not a machine interface to this validator. However, in theory, a catalog that used the same ISO template as we do, could pass their records through the validator using a machine interface and they would also be registered in the Community Catalog WAF.

The ISO Validator also saves records into the local cache, so that the new records are immediately visible in AQ uFIND.

Once the records are in the AQ Comm Catalog (registered in the GEOSS Component and Service Registry), then the GEOSS Clearinghouse harvests the records. Once the records can be found in the Clearinghouse (1 day turn around), then the AQ uFIND queries the clearinghouse and extracts the facet metadata into the local cache.

Help Posts Coming Soon

Coming soon will be posts on:

How to add WMS layer to the uFIND

How to edit a record in uFIND

other topics?

Based on the feedback given for GEO Portal usability we will also include sections to grow:

FAQ

How to search using the uFIND

video tutorials for these functions

General Feedback

This page is for comments about the form/function of the GEOSS Clearinghouse AQ Data Finder.

If you'd rather e-mail: emr1 at wustl.edu or rhusar at wustl.edu

AQ uFIND API

There is an API to the AQ uFIND, so that machines can submit WMS layers to be available through uFIND.

uFIND has an atom feed, that allows significant mashing of querired results with other applications (portals, wms clients etc). uFIND also has csv, json and xml outputs as well.

Time

Temporal extent of data

• WMS:time_min
• WMS:time_max

Space

Spatial extent of data

• WMS:Minx
• WMS:Maxx
• WMS:Miny
• WMS:Maxy

Originator

Organization that the data originally comes from

• Values - list of known originators or add new
• WMS:Originator

Data Distributor

• Values - list of known distributors or add new
• WMS:Distributor

Data Type

describes the structure of the data

• • Values -
    • Grid - Data or models that include
    • Image
    • Point
    • Trajectory

• • WMS:DataType

Vertical

vertical extent that the data covers

• Values -
  • Column - Satellite data measures an integral of the entire column from the satellite to the surface
  • Surface - surface measurements are on the surface
• WMS:Vertical

Time Resolution

how often data is collected

• Values -
  • Day - Data is collected or aggregated over a day or multiple day period
  • hour - Data is collected or aggregated over an hourly period
  • month - Data is collected or aggregated over a monthly period
  • year - Data is collected or aggregated over a yearly period
• WMS:time_unit

Topic Category

ISO topic classification (general subject of the data layer)

• Values - http://gcmd.nasa.gov/User/difguide/iso_topic_category.html
  • Topic categories are another general (mandatory) description of the dataset content. For AQ most datasets are tagged Climatology/Meteorology/Atmosphere
• WMS:TopicCategory

Domain

General topic classification used in DataFed (general subject of the data layer)

Values -

• Aerosol - datasets that measure, model aerosols and precursors
• Demographic - datasets about population
• Emission - emission inventory datasets
• Fire - datasets that relate to fire (fire pixels, smoke)
• GIS - GIS map layers needed for boundaries
• WMS:Domain

Platform

Type of platform measurements were taken from

• Values -
  • Satellite - Satellite datasets
  • Network - Surface Monitoring Network datasets
  • Model - Model datasets
  • Emission - Emission datasets ( SHOULD THIS BE A PLATFORM??)
  • Count - Population count
• WMS:Platform

Instrument

Instrument used to measure data layer

• Values -
• WMS:Instrument

Parameter

Currently, parameter = WMS Layer name. However, parameter will be homogenized so that like parameters from different datasets can be found using the common param names

• Values - Layer name in WMS/WCS
• WMS:Name

Dataset

Grouping of parameters that come from a given dataset

• Values - Free text
• WMS:Dataset

User-Oriented Approach

uFIND is built to enable AQ users to better discover and access data through a combination of spatial and temporal search, faceted search for discovery by different content dimensions and soon tags for grouping data by application or event.

uFIND differs from other clearinghouses and registeries because not only can users find the data, but they can also browse and immediately access data because only OGC WMS and WCS services are registered.

Air Quality uFIND

The AQ uFIND is a user-oriented Filtering and Identification of Networked Data (uFIND). The purpose of uFIND is to provide rich and powerful facilities for the user to discover and choose a desired dataset. These facilities include navigation through the multi-dimensional metadata space through the faceted search (uFind Pilot, 2009), ability to seamlessly access and browse datasets and to use uFINDs facilities as a web service for the mashups with other AQ applications and portals.