Geospatial information: how-to

This document describes how to complete ADN geospatial metadata fields when the geospatial feature being described is associated with Earth. Directions on how to catalog locations on other planets or in the solar system will be provided in the future.

When to use geospatial information

Providing geospatial information is not appropriate for every DLESE resource. Use geospatial information when:

• a spatial footprint referenced to Earth (or other planetary body) is the subject of or primary content of a resource
• its integral to understanding or working with a resource

That is, don't use geospatial information if a resource talks about tundra and then does not define a specific tundra area. Rather if the resource talks about tundra and then makes a point about a specific area in Canada, then include geospatial information. The same goes for the ozone hole. If a specific areal extent of the ozone hole is mentioned, then include geospatial information.

Types of resources for geospatial information

Generally, the following types of resources benefit most from geospatial information:

• Datasets
• Case studies that highlight an event in a certain location
• When geospatial information is important to understanding or working with the resource
• When geospatial information is the primary subject content of the resource
• Remotely sensed imagery
• Photographs of geologic features
• Maps
• Specific events like individual named hurricanes, major volcanic eruptions, named wildfires, earthquakes, tsunami, snowstorms,

Overview of ADN geospatial information

The ADN metadata framework divides geospatial information into two sections:

• Bounding box - a single box encompassing all detailed geometries that is comprised of the western and eastern most longitudes and the northern and southern most latitudes
• Detailed geometries - single points, lines, boxes or polygons encompassing the area of interest represented as a list of individual latitude and longitude coordinate pairs

Both sections need to be completed because bounding boxes should be generated from and encompass detailed geometries. Initially, it is the bounding box information that will be used for digital library search and browse. ADN geospatial information is intended to serve this digital library search and browse; it is not meant for complex representations in GIS systems.

An example: Alaska Volcano Observatory

The Alaska Volcano Observatory provides geospatial information (elevation, latitude and longitude, etc.) on over 50 individual volcanoes. Since there is so much information, this example considers two sections of Alaska, the Aleutian Islands and the Alaskan Peninsula as the areas of interest. Even with just these two sections there are still 20 plus volcanoes. This is still too many volcanoes to individually catalog. Since the Aleutian Islands and the Alaskan Peninsula are recognized geographic areas, this example catalogs each area as a detailed geometry and determines the single overarching bounding box encompassing both areas.

While the resource provides individual latitudes and longitudes for the volcanic points, it does not provide the overarching box' encompassing all the volcanic points nor the coordinates for the Aleutian Islands or Alaskan Peninsula. In this case, a wall map was used to determine the single overarching bounding box. and the detailed geometry boundaries. Based on the wall map, the approximate four edges of a box that encompasses the Aleutian Islands and Alaskan Peninsula. and whose edges are parallel to lines of latitude and longitude are:

Single overarching bounding box

• West = 173 (western most longitude representing on Earth: 173 degrees east longitude)
• East = -154 (eastern most longitude representing on Earth: 154 degrees west longitude)
• North = 59 (northern most latitude representing on Earth: 59 degrees north latitude)
• South = 51 (southern most latitude representing on Earth: 51 degrees south latitude)

Aleutian Islands detailed geometry

Place name: Aleutian Islands

• West = 173
• East = -161
• North = 55
• South = 51

Alaskan Peninsula detailed geometry

Place name: Alaskan Peninsula

• West = -161
• East = -154
• North = 59
• South = 55

As shown above, place name information may be associated with detailed geometries or the overarching bounding box. Because the overarching bounding box encompasses multiple areas, it is not given multiple areas, it is not given a place name while the detailed geometries are their proper names.

Determining additional overarching bounding box data

To fully specify the single overarching bounding box, other pieces of information are required. These include:

• Horizontal or Global Datum - an indication of the base reference in a coordinate system (the initial point of origin)
• Projection type - of the map; projection type applies to the presentation of data in two dimensions; use when the resource displays data (real or modeled) or requires the use of certain paper maps.
• Coordinate system type is the frame of reference specifying the location of an object in space; the only choice right now is DLESE:Geographic latitude and longitude

If these data are obtained by reading a wall map or can not be determined readily, then use the following as their values:

• Horizontal or Global Datum - DLESE:Unknown
• Projection type - use
  • DLESE:Does not apply - when the resource does not display any map data or when determining geospatial coordinates from reading a map
  • DLESE:Unknown - when the resource displays maps but does not indicate the projection used
• Coordinate system type - DLESE:Geographic latitude and longitude

If these data are obtained from:

• the resource directly
• or the resource specifies a specific physical map or a trusted gazetteer
• or the resource does not display any maps but coordinate information is useful and the coordinates are determined from an external and trusted gazetteer

use the following as values:

• Horizontal or Global Datum - as specified by the map, resource or gazetteer.
• Projection type: as specified by the map, resource or gazetteer
• Coordinate system type: DLESE:Geographic latitude and longitude

Completing the metadata fields

Now its time to catalog. This section is geared to resource catalogers using the DLESE Collection System (DCS). However, catalogers or collection builders creating metadata by other means still need to complete the same fields and therefore may find this section helpful in knowing what these fields are.

Overarching bounding box

1. Go to the Geospatial tab in the DCS tool
   
2. Click on add link next to the words GeospatialCoverages
   
   
3. Click on the word body, then in required choice choose Planet
   
   
4. In the Planet element, choose Earth then fill in:
   • geodeticDatumGlobalOrHorz: DLESE:Unknown
   • type (of projection): DLESE:Unknown
   • type (coordinate System): DLESE:Geographic latitude and longitude
   
   
   
5. Now fill in the bounding box information.
   • westCoord : 172.45
   • eastCoord : -154.22
   • northCoord : 59.18
   • southCoord : 51.26
6. And fill in the source (bbSrcName) for this information: since I am determining the coordinates to use, the source is Cataloger supplied
   
   
7. Save your work and go onto the detailed geometries.

Detailed geometries

1. Click on add next to the word detGeoes to create the Aleutian Islands detailed geometry
   
   
2. Fill in the information for
   • typeDetGeo: Bounding box
   • geoNumPts: 4
   • geoPtOrder: Inside
3. Now its time to fill in the longLats elements in the detailed geometry section of the metadata. Enter the longitude and latitudes for each corner of the bounding box. We suggest starting in the upper right corner (the northeast corner), then going clockwise describe the lower right corner (southeast corner), then the lower left corner (southwest corner) and ending with the upper left corner (northwest corner) of the bounding box. Also fill in the source for the information (detSrcName).
   • longLat 1
     • longitude: -161
     • latitude: 55
   • longLat 2
   • longitude: -161
   • latitude: 51
   • longLat 3
   • longitude: 173
   • latitude: 51
   • longLat 4
   • longitude: 173
   • latitude: 59
   • detSrcName: since the coordinates were determined using a wall map, the source is Cataloger supplied
     
   
   
4. Complete the place name that is described by these coordinates. In this case:
   • name: Aleutian Islands, Alaska, United States
   • source: Cataloger supplied



5. Repeat the detailed geometry steps to add the Alaskan Peninsula coordinates and place name. Click on add next to the word detGeoes.
6. Save the record and validate the page. To see the actual catalog (metadata) record for this example, go to http://dcs.dlese.org/preview/admin/view.do?id=SIC-000-000-000-019.

Single location example

coming soon

Additional multiple locations example

For any resource that encompasses multiple locations, adjust the bounding box to encompass all of the locations and add additional detailed geometries for each location. An example with three locations is provided below. The outer bounding box is entered into the bounding box metadata and the longitude and latitude coordinates for Oregon, Mt. Hood, and Colorado are entered into the detailed geometries. The catalog (metadata) record for this example is at: http://dcs.dlese.org/preview/admin/view.do?id=SIC-000-000-000-039. It is often easier to complete the detailed geometries first and then complete the overarching bounding box.

Last updated: 2005-06-09
Maintained by: Katy Ginger (support@dlese.org), DLESE Metadata

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