Systems for data processing, anaylsis and representation

Allam, Mosaad; Plunkett, Gordon

Bibliographic data

Monograph

Persistent identifier:: 1067490280

Title:: Systems for data processing, anaylsis and representation

Sub title:: ISPRS Commission II Symposium : June 6 - 10, Ottawa, Canada

Scope:: 1 Online-Ressource (XX, 530 Seiten)

Year of publication:: 1994

Place of publication:: Ottawa

Publisher of the original:: The Surveys, Mapping and Remote Sensing, Natural Resources Canada

Identifier (digital):: 1067490280

Illustration:: Illustrationen

Signature of the source:: ZS 312(30,2)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Allam, Mosaad; Plunkett, Gordon

Corporations:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Adapter:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Founder of work:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Other corporate:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: [Wednesday, June 8, 1994]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: [Session F-2 WG II/3 - Technologies for Large-Volumes of Spatial Data - Part B]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: SATELLITE DATA MANAGEMENT AND DISSEMINATION AT THE U.S. GEOLOGICAL SURVEY EROS DATA CENTER Lyndon R. Oleson and Thomas M. Holm [...] Darla J. Werner [...]

Document type:: Monograph

Structure type:: Chapter

understanding and the ability to predict change. The Center is also participating in NASA's Earth Observing System (EOS) Program and plans to process and archive land-related data from sensors aboard the EOS polar-orbiting platforms. The Center was selected to serve as one of the principal EOS data archive and distribution facilities because of its demonstrated capabilities to archive, process, and distribute large volumes of data and related products from remote sensing satellite programs. In its role as the National Satellite Land Remote Sensing Data Archive, the Center is continually investigating and exploiting new technologies to ensure the long-term availability of these data. For example, the Center is converting its current holdings of the U.S. Landsat archive to new, more stable archive media. This media conversion effort is providing the opportunity to assess the overall quality of the Landsat archive data and metadata and to collect digital browse images for user viewing through state-of-the-art information systems, such as the USGS Global Land Information System (GLIS). In addition, the Center is experimenting with image data subsetting and compression techniques to improve the overall effectiveness of the delivery of large-scale satellite images over conventional wide-area networks. Following are brief overviews of these examples of technology exploitation by the Center. 2. LANDSAT ARCHIVE MEDIA CONVERSION Landsat data constitute the largest data set in the National Satellite Land Remote Sensing Data Archive. This data set includes more than 634,000 scenes of Landsat Multispectral Scanner (MSS) data, representing approximately 26 terabytes (TB) of data, that were acquired between 1972 and 1989 and are stored on 34,920 high density tapes (HDT). The archive also contains more than 214,000 Landsat Thematic Mapper (TM) scenes, representing approximately 41 TB of data, that have been acquired since 1982 and are stored on approximately 26,000 HDT. To ensure the long-term availability of these data, the Center is converting these data to new, more stable archive media. In 1991, the Center funded the development of a specially configured system called the Thematic Mapper and Multispectral Scanner Archive Conversion System (TMACS) to transcribe the Landsat archive data to Digital Cassette Recording System Incremental (DCRSI) cassette tapes. The DCRSI tape drive implementation was selected because of its proven reliability, 48 gigabyte (GB) storage capacity, incremental buffering capability, and 107 megabyte (MB) per second transfer rate. In addition to transcribing media, TMACS also supports data quality assessment and metadata generation and update operations. After the data have been transcribed to the DCRSI cassette, the tape is played back and a subset of the data is extracted. An orbital model is used to delineate individual scenes by calculating scene center latitude and longitude and the beginning and ending scan lines for each scene. Reduced resolution browse images are produced and visually assessed for cloud cover and image quality. The image data quality information is used to update archive metadata. The browse images are compressed and subsequently transferred to optical disks for access by users of the Global Land Information System. Converting the HDT data to DCRSI cassettes improves the reliability of the data and saves archive space. When the conversion project is completed, more than 39,000 HDT's will have been transcribed to approximately 2,000 digital cassette tapes. The smaller physical dimensions of the DCRSI medium will allow the Center to achieve a 40-to-1 reduction in required archive storage space. The Center has begun a program to monitor data integrity during the lifetime of the DCRSI tapes by using test patterns written at the beginning, middle, and end of each tape during data transcription. The DCRSI recorder's internal bit-error-rate (BER) test generator is used to write and then read the patterns and to compute BER statistics during verification processing. By establishing a baseline BER for each tape and maintaining a history of BER values through subsequent operations, the Center will establish quantitative quality criteria to help identify media degradation as early as possible. In addition, weekly system tests are performed on several prerecorded test tapes, allowing operations staff to verify, by comparing BER values, that the hardware is functioning at an acceptable level. Conversion of the MSS data was begun in December 1992. Concurrent conversion of the TM data was begun in November 1993. At the current production rate, the MSS archive conversion will be completed in June 1994 and the TM data conversion should be completed by the end of 1996. 3. ARCHIVE DATA RECOVERY A major problem encountered during the Landsat archive media conversion project was the recovery of data from tapes affected by hydrolysis. Hydrolysis is the process in which tape binders absorb atmospheric moisture that causes the binders to change chemically, creating a sticky residue buildup on the tape winder and cleaner tissues and rollers, as well as on the tape paths and heads of the tape recorders. This buildup can cause head wear, damage to the tape transport, physical damage to the tape, and the potential contamination of other tapes. Hydrolysis is exacerbated by humid conditions (while tapes are in storage or during transportation), but it also occurs at low humidity over extended periods of time, possibly as part of the natural aging process of older magnetic tapes. Most of the affected tapes at the Center were manufactured between 1978 and 1981 by two manufacturers. The hydrolysis process cannot be stopped; however, it can be temporarily reversed long enough to retrieve the data and copy it to new media. Since April 1993, the Center has successfully recovered more than 15,000 Landsat scenes from nearly 700 affected tapes by applying low levels of heat (130? F) to the tapes for 24 hours to temporarily reverse the degrading condition. This technique, called baking, allows the tape to be played without physical damage to the tape or the drive. Local tests show that data can be 230 recovel In addi! several 4. | The Gl data di by the and ac commu metade about « scientis determ related The da levels : The GI entire « any co geophy (space investi descrif inform: proces The Gi individi GLIS c of Lan holding Admini Radior tempo! invent boundi search In add and in graphi for ma covere service allow 1 interac onan geogr: brows visuall extent GLIS brows Lands TMAC users works; Althou to a vi scienc prove! select invent

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