Introduction
TO
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.
Metadata are used to provide documentation for
data products.
In essence, metadata answer:
who
what
when
where
why
how
about every facet of the data that are being
documented.
Nothing on the back
of this photo,
Who is in the photo?
Back of photos tell who is in the photo,
data of photo, where the photo was taken.
Nothing indicating who is in this photo
Who Are they?
Metadata tells who, what, where and when:
Metadata 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 fullystructured 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-subsections).
 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]).