Federal Geographic Data Committee (FGDC); Public Comment on the Proposal To Develop the ``Content Standard for Digital Geospatial Metadata: Extensions for Remote Sensing Metadata'' as a Federal Geographic Data Committee Standard

DEPARTMENT OF THE INTERIOR

Geological Survey

Federal Geographic Data Committee (FGDC); Public Comment on the

Proposal To Develop the ``Content Standard for Digital Geospatial

Metadata: Extensions for Remote Sensing Metadata'' as a Federal

Geographic Data Committee Standard

ACTION: Notice; request for comments.

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SUMMARY: The FGDC is soliciting public comments on the proposal to

develop a ``Content Standard for Digital Geospatial Metadata:

Extensions for Remote Sensing Metadata.'' If the proposal is approved,

the standard will be developed following the FGDC standards development

and approval process and will be considered for adoption by the FGDC.

In its assigned federal leadership role in the development of the

National Spatial Data Infrastructure (NSDI), the Committee recognizes

that FGDC standards must also meet the needs and recognize the views of

State and local governments, academia, industry, and the public. The

purpose of this notice is to solicit such views. The FGDC invites the

community to review the proposal and comment on the objectives, scope,

approach, and usability of the proposed standard; identify existing

related standards; and indicate their interest in participating in the

development of the standard.

DATES: Comments must be received on or before March 19, 1999. Comments

are accepted at any time however the maintenance organization for this

proposal has the authority to reject comments received after this date.

CONTACT and ADDRESSES: Comments may be submitted via Internet mail or

by submitting electronic copy on diskette. Send comments via Internet

to: www.fgdc.gov">[email protected]www.fgdc.gov. A soft copy version, on a 3.5 x 3.5 diskette

in WordPerfect 5.0 or 6.0/6.1 format, along with one hardcopy version

of the comments may be sent to the FGDC Secretariat (attn: Jennifer

Fox) at U.S. Geological Survey, 590 National Center, 12201 Sunrise

Valley Drive, Reston, Virginia, 20192.

SUPPLEMENTARY INFORMATION: Following is the complete proposal for the

``Content Standard for Digital Geospatial Metadata: Extensions for

Remote Sensing Metadata''.

Project Title: Content Standard for Digital Geospatial Metadata:

Extensions for Remote Sensing Metadata.

Data of Proposal: October 21, 1998.

Submitting Organization: FGDC Standards Working Group, Imagery

subgroup (National Aeronautics and Space Administration (NASA)).

Point of Contact: Benjamin Kobler, NASA Goddard Space Flight

Center, Mail Code 423, Greenbelt, MD 20771. Phone: 301-614-5231.

Electronic mail: [email protected].

Objectives

The purpose of this proposal is to provide extensions to the

Federal Geographic Data Committee (FGDC) Content Standard for Digital

Geospatial Metadata (also referred to hereafter as the Metadata Content

Standard) for metadata describing geospatial data obtained from remote

sensing. Efforts will be made to make these extentions consistent with

the ISO metadata standard under development. Adding these extensions

will provide a way to incorporate the metadata needed for remote

sensing into the Metadata Content Standard.

Scope

These extensions will define content standards for metadata not

defined in the Metadata Content Standard that are needed for describing

data obtained from remote sensing. They will include metadata

describing the observing geometry, the sensor, and the method and

process of deriving geospatial information from raw telemetry. In

addition, metadata to describe granules, the individual files or images

that collectively make up a data product, will be defined.

Justification

Proper use of remote sensing data requires an understanding of how

those data were obtained. While ground-based data are often compiled

from existing data sources without change of form or are obtained by

direct in situ measurement, deriving geospatial data from the

measurements made by remote sensing instruments is often much less

direct. To do so may require knowledge of the observing geometry, the

instrument behavior, and the processing methods and history. In

addition, remote sensing measurements produce large volumes of data,

and users typically do not access the entire data set, only selected

files or frames.

Information about the viewing geometry and the properties and

behavior of the instrument in the FGDC Metadata Content Standard is

limited to the description of the number of points along the raster

axes. The draft ISO metadata standard also includes solar elevation and

azimuth angles and the angle of an image to the vertical.

[[Page 6376]]

However, many users need a more detailed viewing geometry: satellite

orbit or aircraft flight path, platform orientation, and orientation of

instruments relative to the platform. While the proposed ISO standard

includes a number of items in the section of spatial data

representation describing instrumentation not present in the FGDC

Metadata Content Standard, the only calibration information is whether

camera calibration information is available. More information on the

calibration of the instrument, including its dependence on wavelength

and time, is usually required. A standard description of such metadata

should be defined.

Processing of remote sensing data passes through several stages.

The instrument calibration must be applied to the readings communicated

by the raw telemetry and the resulting physical meaurements located

geographically. In some cases, what the instruments measure is not the

final product; for example, radiation measurements may be used to infer

temperatures. Maps and grids may be generated from data at individual

points. Information on the algorithms used for these steps should

accompany the data. In addition, information about the processing

itself, such as what stage a given processing represents, or which

version of processing is represented, is needed. The FGDC Metadata

Content Standard allows for this information an entry for lineage,

which the draft ISO standard has expanded this item to an entire

section on lineage information, but in both cases the content is

unspecified free text. These extensions will define the specific items

that are needed in remote sensing metadata.

The dataset containing results from a remote sensing mission is

large and heterogeneous. Necessary descriptive metadata may not apply

to the entire dataset, but only to individual pictures or files. While

the FGDC Metadata Content Standard has no specific provision for such

granularity, the informative Appendix F to the ISO draft provides but

does not define granule-specific metadata. These extensions will define

the granule-level metadata appropriate to remote sensing.

Benefits

Adoption of these extensions will broaden the applicability of the

Metadata Content Standard to include metadata needed to describe

geospatial data derived from remote sensing. Making this standard

directly relevant to the remote sensing community will encourage its

use. There will be less chance that future producers of remote sensing

data will see the Metadata Content Standard as inapplicable to their

needs and develop separate standards.

Approach

Data standardization and modeling are major research issues within

the Earth Observing System Data and Information System (EOSDIS)

development process. Results of this research, combined with comments

from scientists around the world, from the EOSDIS Data Model Working

Group, and from Earth Science Data and Information System (ESDIS)

staff, have been developed into metadata for the EOSDIS Core System

(ECS). There metadata are described in the Proposed ECS Core Metadata

Standard. This document defines metadata in several areas in the scope

of the extensions to be developed and will be used as a basis of the

extensions covering those areas. The Moderate-Resolution Imaging

Radiometer (MODIS) Level 1A Earth Location: Algorithm Theoretical Basis

Document has a detailed discussion of the information and process

required to derive positions in geographical coordinates given

spacecraft and instrument position and orientation. That discussion

will serve as the basis for the definition of viewing geometry

metadata. As the proposed extensions are to be developed following FGDC

prescriptions, development and adoption is to proceed through the FGDC

Standards Working Group (SWG) procedures. The Imagery Subgroup will

develop these extensions; working scientists with whom it is in contact

will also contribute. Because both metadata and remote sensing

applications are involved, the Metadata Ad Hoc Working Group should be

involved at appropriate stages.

Related Standards

This standard is intended as extended elements of the FGDC Content

Standard for Digital Geospatial Metadata. It will follow the

prescriptions of Appendix D of that Standard, which specifies the

requirements for extended elements. ISO/Technical Committee 211,

Working Group 3 is developing an international standard for metadata;

the current draft is ISO/CD 15046-15. When development of that standard

is complete, it is likely to be considered for adoption by FGDC,

superseding those parts of the current standard where there is overlap.

The ISO standard also has a recommended extension methodology, in

Appendix E. The information there will be used to guide the process of

development of these extensions to the metadata standard. Extensions to

the current FGDC standard covering areas in the ISO standard not in the

FGDC standard will be constructed to be compatible with the ISO

standard.

As noted in the section on approach, the ECS Core Metadata

Standard, which covers many of the areas in the scope of these

extensions, will be used where relevant as a basis for the FGDC

codification.

Schedule

Submission of proposal to FGDC/SWG: November 1998.

Submission of Working Draft to FGDC/SWG: late 1999.

Resources

NASA's ESDIS project will fund the effort required to develop these

FGDC Content Standard for Digital Geospatial Metadata: Extensions for

Remote Sensing Metadata.

Potential Participants

Through the Mission to Planet Earth, NASA already involves many

diverse groups in the remote sensing community. The continuing

standards work for ESDIS has provided considerable insight into the

requirements of these groups. Other federal agencies that produce large

quantities of remote sensing data, such as the National Oceanic and

Atmospheric Administration, the National Imagery and Mapping Agency,

and the U.S. Geological Survey, may also participate in development of

the standard. Contributions will be solicited from the academic remote

sensing community.

Target Authorization Body

The proposed extensions are not specifically targeted for

consideration by any authorizing agency other than FGDC. However, as

efforts to bring the FGDC standard into consistency with the ISO

standard proceed, efforts may be made to gain ISO endorsement as well.

Dated: January 28, 1999.

Richard E. Witmer,

Chief, National Mapping Division.

[FR Doc. 99-3048 Filed 2-8-99; 8:45 am]

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