GES DAAC Improved Tools for Accessing MODIS Data
Abstract
The unique position of the NASA Goddard Earth Sciences Distributed Active Archive Center (GES DAAC) as an intermediary between users and MODIS data led us to explore and develop tools that could help users access and manipulate data. Some tools are DAAC unique extensions like search and order web pages or channel subsetting programs. Other data access and simple visualization tools were developed as MODIS Data Support Team (MDST) work aids The key features of some of the improved tools available from GES DAAC are described below: WHOM: The Web-based Hierarchical Ordering Mechanism (WHOM) is a customized version of the larger GES DAAC web-based data gateway to MODIS data. WHOM offers enhanced graphic interfaces to identify temporal and spatial data coverage while searching and ordering MODIS data archived at the GES DAAC.Calendar page showing dates with available data, visual inspection of the spatial data distribution for the selected region, filtering granules by Day/Night flag, single point and click navigational protocols, and recursive web page generation using templates make this tool unique and attempt to address the needs of the user community. The WHOM for Terra has been operational since February 2000. The same approach is going to be used to provide a gateway to MODIS data on Aqua platform starting May 2002. Subsetting Tools: Calibrated radiance (Level 1B, 1km) channel subsetting is developed as a DAAC unique extension to the EOS Core System (ECS). The front end, a graphic user interface, is an added feature of the WHOM system. The back end is driven by the new Simple Scalable Script-Based Science Processor (S4P) that interacts with ECS for data retrieval, archiving and distribution of the subsetted data. All three resolutions of MODIS Level 1B data will be available for channel subsetting in the future. Visualization Tools: The GES DAAC MDST has developed two very simple IDL-based tools dedicated to mapping MODIS swath products. The first, geoview, has a simple, graphic interface, while the second, simap, is a command line utility. While the two tools are almost identical, simap has the added feature of stitching multiple granules into a single map. HDFLook MODIS : Beta version of this tool has been released recently and it is a product of joint collaboration between the GES DAAC MDST and the University of Lille, France to update the popular HDFLook for future MODIS needs. The program includes multi-level MODIS data functionality and is designed to process all MODIS products. Its main features include re-mapping, geo-projection conversion, interactive and batch mode capabilities, subsetting features, mosaic or stitch, multi-granule processing, and GIS conversion. This presentation will describe methods and tools implemented or planned for the Goddard DAAC that are intended to optimize access to MODIS data for the Earth Science community.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2002
- Bibcode:
- 2002AGUSM.A22B..07O
- Keywords:
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- 3360 Remote sensing;
- 3394 Instruments and techniques;
- 0399 General or miscellaneous