Metadata - Abstracts and Keywords
Animations are interesting by themselves, but the real value comes
when more information is available about the purpose and content of what's being seen.
This information is called "Metadata", or data about the data (the animation in this case).
For the SVS Image Server, there are a number of different kinds of metadata
that can be accessed. These include
Keywords and vocabularies
Related online resources
Let's go back and look more closely at the information about the
African Fires layer in the Capabilities XML. The beginning of the
information about the layer looks like this
<Layer opaque="0" noSubsets="1" fixedWidth="1024" fixedHeight="1024">
<Title>African Fires during 2002 (1024x1024 Animation)</Title>
This animation shows fire activity in Africa from January 1, 2002 to
December 31, 2002. The fires are shown as tiny particles with each
particle depicting the geographic region in which fire was detected.
The color of a particle represents the number of days since a sizable
amount of fire was detected in that region, with red representing less
than 20 days, orange representing 20 to 40 days, yellow representing
40 to 60 days, and gray to black representing more than 60 days.
This data was measured by the MODIS instrument on the Terra satellite.
MODIS detects fires by measuring the brightness temperature of a region
in several frequency bands and looking for "hot spots"
where this temperature is greater than the surrounding region.
This time we see the full abstract. The abstract contains enough information
to clearly describe what it is you are seeing when you look at the animation. The
abstract gives you a frame of reference to understand the animation.
Following the abstract is a keyword list, e.g.,
<Keyword vocabulary="DLESE">Atmospheric science</Keyword>
<Keyword vocabulary="DLESE">Natural hazards</Keyword>
<Keyword vocabulary="GCMD">EARTH SCIENCE:Agriculture:
Forest Science:Forest Fire Science</Keyword>
<Keyword vocabulary="GCMD">EARTH SCIENCE:Biosphere:
Ecological Dynamics:Fire Occurrence</Keyword>
<Keyword vocabulary="GCMD">EARTH SCIENCE:Human Dimensions:
The keywords define some of the subject areas under which the animation might fall.
Since the keyword lists are part of the Capabilities XML, it is up to the client to
use the lists in some way. The WMS specification does not include the capability
for a client to request a list of animations from the server based on a keyword
Note: Some of the keywords have a "vocabulary" attribute. This allows a very strict
categorization of the animations based on a well-defined keyword list. The SVS currently
uses keyword vocabularies from the Digital Library for Earth System Education
and the Global Change Master Directory.
However, the vocabulary attribute was introduced in WMS 1.3.0 and is
not available in WMS 1.1.1.
Go backward to "Styles and Legends"
Go forward to "Metadata - Attributions and FGDC Metadata"