THE GEON LIDAR WORKFLOW AS A DISTRIBUTION PATHWAY FOR COMMUNITY LIDAR TOPOGRAPHY DATASETS

Due to the growing awareness of the power of high-resolution topography from LiDAR for earth science research, it is becoming increasingly common for these datasets to be acquired as a community resource. The forthcoming GeoEarthScope LiDAR topography acquisition is an excellent example of this trend. The GeoEarthScope acquisition offers an unprecedented opportunity to examine the strain field adjacent to major active faults in the western United States at time scales greater than those provided by the Plate Boundary Observatory geodetic instrumentation. Modeled after the recent B4 data acquisition, the GeoEarthScope LiDAR data is expected to provide digital elevation models (DEMs) of one meter or better spatial resolution with scientific-grade geodetic accuracy. These datasets will be exceptionally valuable for geologic slip rate studies, paleoseismic research, and as a pre-earthquake representation of the landscape should an event occur in the near future. These datasets will be utilized extensively and they must be available to the EarthScope community as quickly and as easily as possible.

Traditionally, access to community LiDAR datasets has been difficult because of the massive volumes of data generated by LiDAR technology. For example, the recently acquired B4 dataset covers nearly 1000 kilometers of the southern San Andreas and San Jacinto faults and contains approximately 3.7 billion individual LiDAR returns. With the B4 dataset as a model, the tremendous volume of data generated by the forthcoming GeoEarthScope LiDAR acquisition effort could potentially be a significant barrier for user community access and processing of these data

In order to address the challenges posed by the distribution and processing of community LiDAR datasets, we have applied a geoinformatics approach that capitalizes on cyberinfrastructure developed by the GEON project (http://www.geongrid.org). The internet-based resource we have developed, the GEON LiDAR Workflow (GLW), is designed to democratize access to these challenging datasets and provides tools to enable users to perform basic processing (e.g. DEM generation) of the data. As a proof of concept, we have made four community LiDAR datasets, including the B4 data, available via the GLW. Our approach utilizes a comprehensive workflow-based solution which begins with user-defined selection of a subset of point data and ends with download and visualization of DEMs and derived products. In this workflow, users perform point cloud data selection, interactive DEM generation and analysis, and product visualization all from an internet-based portal. This approach allows users to carry out computationally intensive LiDAR data processing without having appropriate resources locally.

In its proof of concept capacity, the GEON LiDAR Workflow has proven to be a valuable and innovative community gateway for accessing LiDAR topography. As of April 2007, the GLW has 126 users who have processed over 10.5 billion LiDAR returns in 1250 unique processing requests.

As a result of this success, the GLW has been selected as the distribution pathway for the forthcoming GeoEarthScope LiDAR datasets. In order to prepare for these new data, we are currently in the process of migrating the system from its current proof of concept implementation to a fully robust, production level, community data portal. As part of this migration, we are working on a number of enhancements that include improving system stability, documentation and portal usability, adding processing capacity, and providing new job monitoring and job archiving capability.

The distribution of GeoEarthScope LiDAR topography via the GEON LiDAR Workflow represents an excellent example of the utilization of cyberinfrastructure to facilitate access to computationally challenging community datasets.