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ADN Geospatial & Temporal

March 2004

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Geospatial Purpose

Describe geospatial coverage of resources where resources are:– Curriculum, activities, modules etc.– Datasets– Model output– Visuals (maps, satellite imagery)

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Other Geospatial Characteristics

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

DPC - Katy Ginger, Holly Devaul

ADL/ADEPT - Linda Hill, Anita Coleman, Tim Tierney, Greg Janee and David Valentine

Colorado School of Mines - Tom Boyd

NASA - Shelley Olds

Other sources - Ontario Information and Tech. Standards - Metadata Content Spec; DC spec

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Geospatial Framework Concepts (1)

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

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Geospatial Framework Concepts (2)

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

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Geospatial Framework Concepts (3)

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)

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Geospatial Framework Concepts (4)

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)

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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:

– 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)

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Geospatial Framework Concepts (6)

10. Coordinate system - – 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

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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

– 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

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Geospatial Framework Concepts (8)

12. Projection - – 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

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Geospatial Framework Concepts (9)

13. Latitudes and Longitudes - – 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

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

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Temporal Framework Concepts (1)

A. Time AD - the ability to describe date/time ranges like:

– 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

B. Time AD to present - the ability to describe date ranges like:

– 1996 to Present either with time (in UTC) or not– Begin time is specified and end time says ‘Present’

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Temporal Framework Concepts (2)

C. Time BC - the ability to describe date ranges:– -8700 to -2500 BC – Years only, no hourly time

D. Time relative - describe time ranges like:– 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

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Temporal Framework Concepts (3)

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’

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Framework comparisons are next

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Geospatial Comparison IMS vs. ADN

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

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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Geospatial Comparison DC Qualified vs. ADN

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

Datum: yes, free text

Map projections: yes, free text

Coordinate system: geographic

Space: none

Shapes: boxes and points only; no polygons

Elevation: yes

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Geospatial Comparison FGDC vs. ADN

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

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

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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)

Time AD: yes Present: yes Time BC: yes in multiple

units Relative: yes Named periods: yes

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Temporal Comparison DC Qualified vs. ADN

Time AD: yes Present: yes

Time BC: yes in multiple units

Relative: yes Named periods: yes W3C-DTF: yes, dates

required to use it

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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Temporal Comparison FGDC vs. ADN

Time AD: yes Present: yes Time BC: yes in multiple

units Relative: yes Named periods: yes

Time AD: yes Present: no Time BC: no

Relative: no Named periods: yes

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Time and location information

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