Research in GIS Technology

Research questions investigated by the Initiative include:

• To what extent can the emerging GIS interoperability standards address NCAR's legacy data and information systems integration issues?
• Can we articulate abstract requirements for representing and querying time-dependent, real-time, and volumetric data?
• What are the metrics for evaluating the practical limits of general-purpose GIS and relational database technology in atmospheric research?
• Can we develop an atmospheric data model that is general enough to be flexible and specific enough to be useful?

Data Modeling

Together with our colleagues in the atmospheric community and ESRI, the GIS Initiative has been working on the development of an Atmospheric Data Model. The goal for the ArcGIS Data Models is to provide practical templates for implementing GIS projects for specific industries and applications. Data Models are designed by a consortium of ESRI GIS users and provide frameworks, built on accepted standards, for modeling and capturing the behavior of real-world objects in a geodatabase. Recently developed Data Models in hydrology and oceanography are good examples.

The GIS Initiative at NCAR serves as a catalyst to drive the Atmospheric Special Interest Group (SIG) in development of a Data Model for atmospheric research. The SIG is led by the GIS Initiative at NCAR and has participants from several government agencies, universities, research labs and private sector.The data modeling efforts established a working dialog between ESRI and the atmospheric sciences community about data representation issues and to address the needs of the atmospheric community in ESRI software development, for example temporal data management and improved raster data support. For more information about SIG and atmospheric data modeling visit Atmospheric SIG's website.

Integration through Web Services

GALEON - Geo-interface for Atmosphere, Land, Earth, and Ocean netCDF Interoperability Experiment

The GALEON project's aim is to facilitate the interaction between GIS and Earth System Science communities through open protocols and standards. The project is testing the effectiveness of incorporating Web Coverage Server (WCS) for serving netCDF datasets via netCDF, THREDDS, OPeNDAP client/server technology. There are a number of collaborators in the GALEON project but the initiators in the project are : UNIDATA/UCAR, IMAA-CNR, George Mason University, and NASA Geospatial Interoperability Office.

GIS Demonstration Project

One of the core demonstration projects explores application of GIS interoperability technologies to a meteorological field experiment – the International H2O Project (IHOP2002). The GIS demonstration project aimed at exploring both commercial and open source approaches to spatial data interoperability in GIS environments. The first approach makes use of Open GIS Consortium (OGC) specifications (WMS and WFS) to connect the subset of IHOP2002 data archive to custom-built software infrastructure (TITAN) developed at NCAR for managing the complex demands of large temporal-spatial databases for meteorological applications. The second approach uses OGC-compliant ESRI GIS that provides a geo-referenced, relational database available for further GIS analysis in ArcGIS and web-based (ArcIMS) data access and distribution.

Types of data collected during the IHOP2002 included aircraft, GPS, land surface, lidar, mesonet, model outputs, photography, wind profilers, radar, radiation, satellite, and soundings.

The selection of subset of IHOP2002 data was based on the following criteria:

1. Level of dataset demand among IHOP2002 researchers
2. Applicability to scientific collaborators involved in this GIS demonstration project (e.g., land surface – atmosphere interactions)
3. Availability of associated geo-referenced meta-data
4. Availability of existing data format decoders

Based on the selection criteria, the GIS demonstration project focused on upper air soundings, surface mesonet, aircraft observations and radar data.

GIS demonstration project report

IHOP Focus:
The International H2O Project (IHOP2002) was conducted in the Southern Great Plains of the United States in May-June 2002. The goal of IHOP2002 was improved characterization of the four-dimensional distribution of water vapor and its application to improve the understanding and prediction of convection. The large number of researchers, sensors, and datasets involved in IHOP2002 along with widely varying needs for spatial data display, analysis, and dissemination, provided a great opportunity for exploring the strengths and limitations of current GIS technologies in meteorological applications.

NSF Sponsorship:
The GIS demonstration project received its funding from the NSF Special Funds.

 

OGC/CITE Participation

The Open GIS Consortium (OGC) is currently developing a Web site for conformance and interoperability testing. This OGC initiative, CITE (Conformance and Interoperability Test and Evaluation Initiative), will allow developers of Open GIS standards to verify that their products meet the standards requirements.  As part of the CITE project, NCAR is hosting the official reference implementations of the WMS and WFS servers.

The Deegree reference implementation of WMS 1.1.1 is a free software initiative founded by the GIS and Remote Sensing unit of the Department of Geography, University of Bonn, and lat/lon and can be downloaded from http://deegree.sourceforge.net/

The GeoServer reference implementation of WFS 1.0 is built on top of the GeoTools2 open source mapping toolkit and is freely available from http://geoserver.org/