The Earth System Grid

1
The Earth System Grid

• The Challenges of Building Web Client Geo-Spatial
  Applications
• Eric Nienhouse
• NCAR

2
Outline

• A Case Study of UI Development
• Brief Overview of the Earth System Grid
• Focus on User Interface for Visualization
• Present User Feedback and Technical Challenges
• Consider Next Steps in UI Development

3
What is the Earth System Grid?

• Distributed System of Gateways and Data Nodes
• Access Control and User Management
• RDF Metadata Search
• Data Access and Download
• Collection Browsing
• Collection Tagging and Annotation
• Deep Storage Data Transfer and Monitoring
• Visualization and Data Products
• Model Comparison
• Use Metrics and Reporting

4
User Interface for Visualization

• Basic Requirements
• Provide ability to visually identify data of
  interest
• Usable by wide range of technical abilities
• Support future needs of comparison and
  sub-setting
• Integrate with gateway context and look and feel
• Flexible enough to adapt to new backend services
• Functional enough to generate feedback

5
User Interface for Visualization

• Alpha Process How We Started
• Lightweight client based on JavaScript/Ajax
• Use Live Access Server to deliver visualization
• OpenDAP and aggregation capabilities of TDS
• Develop within Java/Spring gateway framework
• Use known Google Maps API

6
User Interface for Visualization

• Initial Prototype
• Google Map API
• Custom selection overlay
• Dojo JavaScript Toolkit
• Tree based selection
• Ajax application with JSON
• Proxy client to access LAS
• LAS Armstrong v 0.4
• TDS v 3.16

7
Component Communication

• Proxy Client
• Request pass through to LAS
• Avoid browser security
• Augments LAS capabilities
• Preserves gateway context
• Allows Flexibility

8
Initial Prototype

• Feedback and Lessons Learned
• Single page UI is an improvement over wizard
• Screen real estate must be used wisely
• Tree based UI tedious for some
• User reset of region is critical for usability
• Visualization tools excite people and yield
  feedback
• People look closely at dataset and variable names
• Visualization helps identify data problems
• Dojo toolkit is good but poorly documented
• TDS aggregations LAS is a powerful combination
• Configuration of TDS and LAS must be automated

9
User Interface for Visualization

• Back to the Drawing Board
• Review of feedback
• Wire-frame drawings
• Basic formal specification

10
User Interface for Visualization

• Second Prototype
• YUI user interface
• Improved real estate use
• Improved state indication
• Pre initialized dataset and variable
• Ajax application with JSON
• Proxy client access to LAS
• Place holder for sub-setting UI
• LAS V7 Beta
• F-TDS v 3.16

11
Second Prototype

• Feedback and Lessons Learned
• Differing communities have diverse abilities
• Modeling community prefers to access data
  directly
• Simplified work flows needed for some user groups
• Combine selection and presentation UI for
  efficiency
• Averaging and analysis functions are desired by
  many
• Plot legends, times and source data labels are
  important
• Variable names must be consistent
• TDS NcML critical in making data
  visualize-able
• Delayed delivery is important consideration for
  UI
• Saving regions of interest and product result are
  desired
• Polar projections unlikely to be supported by
  Google Maps
• Firebug extremely useful debugging tool
• JavaScript frameworks produce browser
  incompatibilities

12
Next Steps

• What will we do with these findings?
• Collect more feedback from ESG test-bed
  deployment.
• Consider formalizing user studies and
  observations
• Expose more analysis features of LAS
• Add multi-variable selection for analysis,
  sub-setting, layering
• Integrate geographic selection with search tools
• Explore more polar capable UI components
• Explore WMS visualization capabilities
• Exploit more of the F-TDS analysis, sub-setting
  capabilities
• Continue to refine and improve quality of the UI
• Encourage community convergence on UI best
  practices

13
Thank You!

• In particular
• Ansley Manke, PMEL
• Roland Schweitzer, PMEL
• John Caron, UNIDATA
• Collaborators at ANL, LBNL, PCMDI and many
  others

14
Questions?