Page 1 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 The Development of Remote-Sensing Related Standards at FGDC, OGC, and ISO TC 211 Liping Di Laboratory for Advanced Information Technology and Standards (LAITS) George Mason University 9801 Greenbelt Road, Suite Lanham, MD 20706, USA Presented at IGARSS03

Page 2 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 Introduction Remote sensing is one of the major methods for collecting geospatial data. Both public and private sectors have been involved in the remote sensing activities. Remote sensing data have been widely used in all aspects of human socio-economic activities, ranging from the global change research to decision making. Those research and applications normally requires data collected by multiple sensors and provided by different data providers. Those data are normally analyzed by users through GIS/Image process systems to derive useful information. Without basic standards for remote sensing data and system, it is very difficult –To integrate data from multiple sources. –To share data among the data providers and users –To interoperate between data systems.

Page 3 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 The standard-setting organizations Because of importance of the standards for the remote sensing, many geospatial organizations are working on setting the standards –Agencies/internal standards –Industry standards –Federal standards –National standards –International standards The notable standard organizations from which the remote sensing standards are introduced in this presentation are: –Open GIS Consortium (OGC) : Industry standards –U.S. Federal Geographic Data Committee (FGDC) : Federal standards – International Organization for Standardization (ISO) Technical Committee 211 (ISO TC 211) : International Standards

Page 4 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 The Federal Geographic Data Committee (FGDC) FGDC is an interagency committee, organized in 1990 by the U.S. Federal Government, to promote the coordinated use, sharing, and dissemination of geospatial data on a national basis –FGDC is responsible for coordinating the implementation of National Spatial Data Infrastructure (NSDI). FGDC standards are mandatory-if-applicable to all U.S. federal agencies. FGDC standards are very influential because –U.S. Federal Government is the largest geospatial data producers and consumers. –Many FGDC standards have been the basis for the corresponding ISO standards. –OGC also uses the FGDC standards as the basis for some of its implementation specifications.

Page 5 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 FGDC Content Standard for Remote Sensing Swath Data Swath data is one of the major forms of the remote sensing data –They are produced by scanning and profiling types of remote sensors and provided geometrically in the sensor coordinate system. –Most of low-level remote sensing data are of this type. The swath standard provide the standard data model for the swath data. –Define the mandatory and optional components –Define the geolocation information –Define the relationship between components and how to apply geolocation information to sensor measurement. It is not a swath encoding standard but provides the basis for developing such a standard A compliant product has to have all mandatory components available in the product with the content defined in the standard, regardless how the product is encoded and distributed.

Page 6 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 FGDC Content Standard for Geospatial Metadata: Extensions for Remote Sensing Metadata This standard is the extensions to the FGDC metadata standard to include remote-sensing specific metadata –The geometry of the measurement process –The properties of the measuring instrument and platform –The processing of raw readings into geospatial information –The distinction between metadata applicable to an entire collection of data and those applicable only to component parts The standard establishes the names, definitions, and permissible values for new data elements and the compound elements of which they are the components. These new elements are placed within the structure of the FGDC Metadata Standard, allowing the combination of the original standard and the new extensions to be treated as a single entity.

Page 7 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 The FGDC Orthoimagery Standard The FGDC standard defines the orthoimagery theme of the digital geospatial data framework as envisioned by the FGDC. –Set a common baseline that will ensure the widest utility of digital orthoimagery for the user and producer communities through enhanced data sharing and the reduction of redundant data production. –Stress complete and accurate reporting of information relating to quality control and standards employed in testing orthoimagery data. –Describe processing, accuracy, reporting, and applications considerations for NSDI Framework digital orthoimagery, and may be applicable to other data sets which employ the FGDC Framework concepts. In order to support the U.S. geospatial one-stop initiative, the standard is currently being modified to become a U.S. national standard

Page 8 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 The Open GIS Consortium (OGC) The OGC is a not-for-profit international membership- based organization founded in 1994 to address the lack of interoperability among systems that process georeferenced data, and between them. The main work of OGC is to develop the interoperability specifications through the testbed and consensus processes. There are two types of specifications: –Abstract: the high level guide providing the framework or reference model for geographic information. –Implementation: the unambiguous technology platform specifications for implementation of standard geo-processing software interfaces

Page 9 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 OGC Abstract Specifications Currently there are 16 abstract specifications The most important ones to remote sensing are –Topic 7: Earth Imagery –Topic 15: Imagery Exploitation Services, –Topic 16: Image Coordinate Transformation Services. Based on the agreement between OGC and ISO TC 211, OGC will replace those abstract specifications with relevant ISO standards when such standards are available.

Page 10 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 OGC Implementation Specifications OGC implementation specifications are very influential and are recognized as the international industry standards for geographic information systems. A large number of OGC implementation specifications are either endorsed by OGC or in some stages of the development processes. The most relevant ones to remote sensing include: –the Web Coverage Service (WCS) specification –the Web Map Service (WMS) specification, –the Sensor Markup Language (SensorML) specification.

Page 11 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 OGC WCS Specification OGC WCS Specification defines the interfaces between web-based clients and servers for accessing on-line coverage data in an interoperable way. – multi-dimensional geospatial data (Grid coverage), TIN, etc –All imagery types of remote sensing data, both high-level (georectified products) and low-level (swath) products are covered by the specification (e.g., multiple bands, time-series, etc). OGC Web Map Testbed-II MT-II developed the first version of WCS (0.4). DTD-based WCS 0.5 was the baseline version of WCS in OWS 1.1 OWS-1.1 developed schema-based WCS 0.6 and 0.7. OWS-1.2 is improving the WCS through the image handling thread. Currently, the WCS specification is going through the specification program to become an official OGC spec. (Expected to release WCS 1.0 in later 2003).

Page 12 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 OGC WMS Specification OGC WMS spec defines web interfaces for interoperability of map assembly and delivery middleware within a heterogeneous distributed computing environment over Internet. It is one of the most widely implemented OGC specifications. The initial version was tested in Web Map Testbed-1 and has been continuously improving and updating in the follow-on initiatives. The most current version of the official spec is version Work is underway to update the version and to be released in later The WMS version 1.0 is working through ISO TC 211 to become an international standard.

Page 13 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 SensorML SensorML is an XML schema currently being developed as a potential standard Technical Specification under the OpenGIS Consortium. –provide a functional description of virtually any sensor system including an in-situ or remote sensor on either a stationary or dynamic platform. –describe information needed for discovery, processing, and geolocation of sensor observations. SensorML initiated under the auspices of the Committee for Earth Observation Satellites (CEOS) and funded by NASA, EPA, and NIMA. It continuously developed under Sensor Web Enablement (SWE) thread of OGC OWS Initiative 1.1 and 1.2. In December 2002, OGC Technical Committee approved SensorML for public release as a Discussion Paper. The development of SensorML is also closely collaborated with the development of ISO

Page 14 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 The ISO TC211 A technical committee under the International Organization for Standardization (ISO). It is responsible for setting international standards on geographic information. Since 1997, ISO TC 211 has been worked on developing international standards in the area of the imagery and gridded data, which includes remote sensing data. –ISO Imagery and Grid Data –ISO Imagery and gridded data components –ISO Imagery, gridded and coverage data framework –ISO Sensor and data models for imagery and gridded data –ISO Metadata: Extensions for imagery and gridded data Potential new TC211 projects –Reference for Imagery –Radiometric calibration and validation for remote sensing data –Rules for encoding imagery data

Page 15 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 ISO and ISO ISO is a stage 0 project to produce a technical report, started in 1997 and finished in The Technical Report-ISO/TR 19121:2000 outlines: –Standards currently used for the imagery data. –Needs for standardization in I&G data –Possible areas needed for standardization. –Suggestion the way for ISO TC 211 to handle the I&G data Proposed to explore the components in I&G that need to standardization. ISO is a follow-on stage 0 project of ISO 19121, started in 1999 and finished in Produced a review summary containing: –Framework of imagery and gridded data Term definitions and the conceptual hierarchy UML model of I&G data –Five components Data model, Metadata, Encoding, Services,Spatial registration. Impact on existing ISO TC 211 standards/projects –Suggested two new work items Stage 1 of I&G project International standard on sensor and data models

Page 16 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 ISO Imagery, Gridded and Coverage Data Framework The project was started in 2001 and is going on now. The project will develop an international technical specification to standardize concepts for the description and representation of imagery, gridded and coverage data in the context of the ISO suite of standards. The technical specification addresses five areas identified in ISO 19124, including data model (or schema), metadata, encoding, services, and spatial registration. The project also serves as the spawning ground for new ISO projects in the related areas.

Page 17 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 ISO Sensor and Data Models for Imagery and Gridded Data It is a spin-off project of ISO approved by ISO TC 211 in March It will specify a sensor model describing the physical and geometrical properties of each kind of photogrammetric, remote sensing and other sensors that produces imagery type of data. It will define a conceptual data model that specifies, for each kind of sensor, the minimum content requirement and the relationship among the components of the content for the raw data that was measured by the sensor and provided in an instrument-based coordinate system, to make it possible to geolocate and analyze the data. Currently experts from nine countries and four organizations form the project team The FGDC Swath Standard is the basis for data models part of the standard.

Page 18 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 ISO Part 2: Metadata: Extensions for Imagery and Gridded Data This project was approved by ISO TC 211 in May It will develop imagery-specific metadata standard that covers the imagery (including remote sensing) metadata currently not covered by the ISO The first working draft of standard is based on the FGDC Content Standard for Geospatial Metadata: Extensions for Remote Sensing Metadata. Addition metadata elements will be added during the development process, including –motion pictures –model outputs

Page 19 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 Future ISO TC 211 Standards for Remote Sensing Reference for Imagery –Currently in ballot for approval by ISO TC 211 members –Define an imagery reference model using ISO viewpoints, which include computational viewpoint, information viewpoint, and engineering viewpoint. –The reference model will guide the development of imagery-related standards and provide the framework for fitting different imagery-related standards together. Radiometric calibration and validation for remote sensing data –Currently in proposal stage –Define the parameters needed for describing sensor’s radiometric properties, the radiometric fidelity of the sensor data, and the validation of the radiometric fidelity. Rules for encoding imagery data –Define the rules for encoding imagery data for georeferenaible and georectified data in both embedded metadata and separated metadata cases. –Provide examples of implementing those roles in commonly used standard remote sensing format, such as JPEG2000, BIIF, GeoTiFF, and HDF-EOS.

Page 20 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 Harmonization of Standards Harmonization efforts among FGDC, OGC, and ISO TC 211 on remote sensing standards are currently going on. OGC is an official external liaison organization of ISO TC 211. The cooperative agreement between ISO TC 211 and OGC promote the cooperation between the two organizations for developing geographic information standards. –OGC will adopt relevant ISO series of standards as its abstract specifications while submitting the implementation specifications to ISO TC 211 for approval as official international standards. ISO Simple Feature Access ISO Web Map Server Interface ISO Geographic Markup Language. OGC experts have been involved heavily in the developing ISO and ISO standards. The SensorML is considered to be an implementation of ISO and will be included as informative part of the ISO standard. FGDC is a principal member of OGC and is a sponsor of several OGC interoperability initiatives. –FGDC remote sensing standards have been tested in those initiatives and serves as one of the basses for the development of OGC implementation specifications. –FGDC standards have been used as the basis for a number of ISO Standards

Page 21 LAITS Laboratory for Advanced Information Technology and Standards Duh 7/10/03 The Use of Remote Sensing Standards Standards have to be used to build an interoperable geospatial data/information infrastructure, we need to use standards. Based on the function of a standard, it can be classified into four categories: access technology, content, organization, or education categories. –The ISO family of standards touches all four categories of the geospatial interoperability standards –OGC specifications mainly deal with access technology –FGDC standards, which are mandatory to all applicable federal agencies, are mainly for the data content. At the current stage, building an interoperable data server for providing on-line data access of remote sensing needs to use the following standards: –ISO and OGC standards for the system conceptual design –OGC/ISO specifications for the system interface implementation –ISO and FGDC standards for data and metadata contents and product generations.