IntroductionTO

Metadata!Gary Johnson

Nevada Bureau of Mines & Geology

What we will talk about

What metadata are?

Metadata tools (ArcView extension)

www.FGDC.com

What are METADATA?

Metadata consist of information that characterizes data.

In essence, metadata answer:who

whatwhen wherewhyhow

about every facet of the data that are being documented.

Metadata are used to provide documentation for data products.

Back of photos tell whoBack of photos tell who is in the photo, is in the photo, data of photo, where the photo was taken.data of photo, where the photo was taken.

Nothing on the back of this photo,

Who is in the photo?

Nothing indicating who is in this photoWho Are they?

Metadata tells who, what, where and when:

Metadata placed on back of photoMetadata placed on back of photo

Why should I create metadata?

Metadata helps publicize and support the data you or your organization have produced.

Metadata explains what you have done when you are no longer with the agency.

Metadata that conform to the FGDC standard are the basic product of the National Geospatial Data

Clearinghouse, a distributed online catalog of digital spatial data. This clearinghouse will allow people to understand diverse data products by describing them in a way that emphasizes aspects that are common among them.

Who should create metadata?Data managers who are either technically-literate scientists or scientifically-literate computer specialists.

Creating correct metadata is like library cataloging, except the creator needs to know more of the scientific information behind the data in order to properly document them.

Don't assume that every -ologist or -ographer needs to be able to create proper metadata. They will complain that it is too hard and they won't see the benefits.

But ensure that there is good communication between the metadata producer and the data producer; the former will have to ask questions of the latter.

How do we deal with people who complain that it's too hard?

The solution in most cases is to educate the creator of the data to use an easy tool rather than to develop new tools.

People often assume that data producers must generate their own metadata. Certainly they should provide informal, unstructured documentation, but they should not necessarily have to go through the rigors of fully-structured formal metadata.

The Real Question is:

If I already know what meta data are, why am I here?– To learn how to compile your meta data in a

standard format. • Just like a recipe.

• Just like a book is catalogued in the library.

• Just like a step-by-step how-to instruction manual.

Why Can’t I Just Write Readme Files? Readme files vary in the amount and quality

of information they contain.

You will be writing “readme” files, that are in a standardized format that can be searched on-line, and contain the kinds of information that we would all like to see in a “readme” file.

The “Standard”

The Federal Geographic Data Committee (FGDC) was assigned the task of developing a “standardized documentation of data” through Executive Order 12906.

What they came up with was the Content Standard for Digital Geospatial Metadata (CSDGM).

www.fgdc.gov/metadata/contstan.html

Objective of the Standard

To provide a common set of terminology and definitions for the documentation of geospatial data.

Developed from the perspective of defining information required by a prospective user.

Spatial Data vs Digital Spatial Data

Spatial Data (in the form of a paper map) has a legend that displays the information (the meta data) about the map.

Digital Spatial Data has no legend, so a conscious effort is required to develop and maintain the information (meta data) that goes with the data.

Information Required by a User

Availability -- Does data exist for the geographic location I’m interested in?

Fitness For Use -- Does the data meet my specific needs?

Access -- How do I acquire a specific data set?

Transfer -- How do I process & use the data?

Organization of the Standard (derived from the FGDC’s CSGDM)

Hierarchy of compound elements and data elements (sections, sub-sections, sub-sub-sections).

Each compound element (section) is individually numbered and also contains compound elements (sub-sections) and data elements (sub-sub-sections).

Conventions for Dates (These dates use ANSI

X3.30-1985: New York, American National Standards Inst.)

Calendar Dates (year, month, day)– YYYYMMDD– YYYY = year– YYYYMM = year and month– YYYYMMDD = year, month and day

Conventions for Time of Day(These times use ANSI X3.43-1986): New York, American National Standards Inst. And X3.51-1975, also known as FIPS 59)

Local Time.– 24 Hour clock - HHMMSSSS

Local Time with GMT Differential.– Four-digit number preceded by a (+) or (-)

indicating hours that local time is ahead (+) or behind (-) GMT. HHMMSSSSshhmm. (Pacific time differential = -0800).

GMT (Greenwich Mean Time)– HHMMSSSSZ (‘Z’ indicates GMT)

Conventions for Latitude and Longitude (values generally use FIPS 70-1) Expressed as decimal fractions of degrees.

– Whole degrees of latitude: 2 digit decimal number from 0-90.

• North of equator shall have + or nothing, south of the equator shall have -

– Whole degrees of longitude: 3 digit decimal number from 0 - 180.

• East of prime meridian shall have + or nothing, west of the prime meridian shall have -

Nevada is: -120.13959893 west; -113.79699228 east; 41.98877104 north; 34.99577381 south

Meta Data Resources: The web has a number of resources to learn more

about meta data. A couple of places to start are: www.fgdc.gov (links to other sources, examples of

meta data, meta data collection tools, and clearinghouse node).

www.lic.wisc.edu/metadata/metaprim.htm (meta data primer).

www.blm.gov/gis/metadata.html (Barney - The Meta data Hero! [a meta data tutorial]).