Transcript Geospatial Overview - Digital Library for Earth System

ADN Geospatial & Temporal
March 2004
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Geospatial Purpose
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Describe geospatial coverage of resources
where resources are:
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Curriculum, activities, modules etc.
Datasets
Model output
Visuals (maps, satellite imagery)
Other Geospatial Characteristics
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Describes location information
Does not describe individual variables of
datasets or model output (e.g. ozone, SST)
Is independent of temporal characteristics
Development period - Jan 2000 to June 2002
with some implementation fixes in Dec 2002
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Geospatial Development Team
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DPC - Katy Ginger, Holly Devaul
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ADL/ADEPT - Linda Hill, Anita Coleman, Tim
Tierney, Greg Janee and David Valentine
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Colorado School of Mines - Tom Boyd
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NASA - Shelley Olds
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Other sources - Ontario Information and Tech.
Standards - Metadata Content Spec; DC spec
Geospatial Framework Concepts (1)
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1.
Overarching Bounding Box - a single
overall, geometric footprint on the surface of a
planet or moon in our solar system described
with a 4 vortex box in geographic latitude and
longitude
2.
Detailed Geometries - detailed geometric
footprints (polygons, lines, points) within the
Overarching Bounding Box
Geospatial Framework Concepts (2)
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3.
Elevation - the vertical min & max of
footprints (overarching box & detailed geos)
with reference to ground or datum level
4.
Planet or other body - the planet or body in
our solar system for the geospatial footprint
Geospatial Framework Concepts (3)
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5.
Place-name tied to coordinates - the name
of a location that is specified by a footprint
(e.g. N=41°, S=37°, E=-102°, W=-109° is
Colorado, United States
6.
Place-name not tied to coordinates location name not specified by a geospatial
footprint; (keyword searching only)
Geospatial Framework Concepts (4)
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7.
Event-name tied to coordinates - the name
of an event that occurred in the area specified
by the geospatial footprint (e.g. N=45°, S=22°,
E=-62°, W=-86° is Hurricane Fran in 1996
8.
Event name not tied to coordinates - an
event within an area that is not specified by a
footprint; (keyword searching only)
Geospatial Framework Concepts (5)
9.
Objects in space - the location of objects
(e.g. nebulas) that are not within our solar
system; described using the conventions of:
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Right ascension (0 <= hours <= 24)
Declination (-90 <= degrees <= 90)
Epoch (50 year steps to redraw celestial grid due
to equinox progress. epoch1950.0 / epoch2000.0)
Geospatial Framework Concepts (6)
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Coordinate system –
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a frame of reference specifying the location of an
object
DLESE uses overarching bounding box so only
Geographic latitude and longitude can be the
coordinate system
visuals, raw and gridded data use coordinate
system
Geospatial Framework Concepts (7)
11.
Datum - base reference in a coordinate
system; the position of an initial point of origin
and orientation of an ellipsoid that models the
surface of the earth in the region of interest.
Datums apply to coordinate systems
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Horizontal - NAD27, NAD83, ATS77
Vertical - Sea level ,CGD28-CDN, NAVD29-USA,
NAVD88, IGLD88
Global - WGS72, WGS84 (GPS use), PZ-90
Other and Unknown is allowed
Geospatial Framework Concepts (8)
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Projection –
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systematic presentation (think 2-D maps) of
objects on the Earth or the celestial sphere using
coordinate lines on a flat surface
different projections represent different parts of the
Earth better (polar stereographic versus satellite)
only visuals, not gridded or raw data, use
projection
Other, Unknown and Does not apply are allowed
Geospatial Framework Concepts (9)
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Latitudes and Longitudes –
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West longitudes: -180 to 0
East longitudes: 0 to 180
North latitudes: 0 to 90
South latitudes: -90 to 0
All in decimal degrees and not degrees/minutes
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Temporal Purpose & Characteristics
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Describe date/time characteristics of resources
Like geospatial, not meant for individual
variables rather a broad sense of time
Is independent of geospatial coverage
Development period - May 2002 to Dec 2002
Development team - Katy Ginger, Ethan Davis
(THREDDS) and the ISO 8601 standard
Temporal Framework Concepts (1)
A.
Time AD - the ability to describe date/time
ranges like:
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B.
Time AD to present - the ability to describe
date ranges like:
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1965-06-23 12:00:00Z to 1974
1492 to 1505 either with time (in UTC) or not
Begin and end times must be specified
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1996 to Present either with time (in UTC) or not
Begin time is specified and end time says ‘Present’
Temporal Framework Concepts (2)
C.
Time BC - the ability to describe date ranges:
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D.
Time relative - describe time ranges like:
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-8700 to -2500 BC
Years only, no hourly time
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30 days ago to 0 days ago (present)
1.2 billion years ago to 1.0 thousand years ago
100 years forward to 1000 years forward (for use
in modeling climate change)
Begin & end times must be specified
Temporal Framework Concepts (3)
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E.
Named time period - the ability to associate
specified date/time information with a named
time period like 1920 to 1930, e.g. ‘The
Roaring 20's’. Sources for the name must be
indicated, e.g., ‘cataloger provided’
F.
Simple time period - the ability to name a
recurring named time period without
associating specified date/time information,
e.g. ‘spring semester’, ‘fall’
Framework comparisons are next
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Geospatial Comparison
IMS
vs.
ADN
The spatial and/or temporal
characteristics of the resource
in free text.
Formal specification of
COVERAGE is currently
under development.
Users and developers should
understand that use of this
element is currently
considered to be
experimental. (Sept. 2001)
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Datum: NAD83, NAVD 88
and others (contrlled vocab)
Map projections: several
choices (contrlled vocab)
Coordinate system:
geographic
Space: planets & other
objects (nebulas)
Shapes: boxes, points,
polygons
Elevation: yes
Geospatial Comparison
DC Qualified vs.
ADN
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Datum: yes, free text
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Map projections: yes, free
text
Coordinate system:
geographic
Space: none
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Shapes: boxes and points
only; no polygons
Elevation: yes
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Datum: NAD83, NAVD 88
and others (contrlled vocab)
Map projections: several
choices (contrlled vocab)
Coordinate system:
geographic
Space: planets & other
objects (nebulas)
Shapes: boxes, points,
polygons
Elevation: yes
Geospatial Comparison
FGDC
vs.
ADN
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Datum: NAD83 and NADV 88
only
Map projections: More
extensive list
Coordinate system:
geographic
Space: none
Object type: raster and
vector
Shapes: boxes, points,
polygons
Elevation: yes
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Datum: NAD83, NAVD 88 and
others (contrlled vocab)
Map projections: Less
extensive list (contrlled vocab)
Coordinate system:
geographic
Space: planets & other objects
(nebulas)
Object type: none
Shapes: boxes, points,
polygons
Elevation: yes
Temporal Comparison
IMS
vs.
ADN
The spatial and/or temporal
characteristics of the resource
in free text.

Formal specification of
COVERAGE is currently
under development.

Users and developers should
understand that use of this
element is currently
considered to be
experimental. (Sept. 2001)
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Time AD: yes
Present: yes
Time BC: yes in multiple units
Relative: yes
Named periods: yes
Temporal Comparison
DC Qualified vs.
ADN
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Time AD: yes
Present: sort of; done as a
named time period
Time BC: sort of; done as a
named time period
Relative: no
Named periods: yes
W3C-DTF: yes, but dates are
not required to use it
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Time AD: yes
Present: yes
Time BC: yes in multiple units
Relative: yes
Named periods: yes
W3C-DTF: yes, dates
required to use it
Temporal Comparison
FGDC
vs.
ADN
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Time AD: yes
Present: no
Time BC: no
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Relative: no
Named periods: yes
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Time AD: yes
Present: yes
Time BC: yes in multiple units
Relative: yes
Named periods: yes
Time and location information
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Searchable in ADN (controlled fields)
Not searchable in IMS (non-existent)
Dependent on metadata quality in DC
(because free text)
Searchable in FDGC (but time limited to A.D.)
ADN plays well in the FDGC world
ADN encompasses the big 3 of geospatial,
time & education for effective search