ASTER User's Guide - Aster - NASA

ASTER Users Handbook
What is User-Friendly Metadata (UFM) and how can I use it to make my metadata file
friendlier to use?
Since there is a large volume of metadata that is produced along with ASTER Level-1 datasets, it
is not always practical to print the entire metadata file which can run into many pages. User
Friendly Metadata (UFM) is a utility that helps condense and reformat your metadata file into a
more usable size. It outputs the metadata to a hypertext markup language (html) file that can be
viewed using any web browser. It is available for all flavors of UNIX and NT platforms. It is
available free of charge and can be downloaded from:
http://hdfeos.gsfc.nasa.gov/hdfeos/SoftwareDist.html.
On average, it condenses an ASTER L1 metadata file from 84,000 bytes to 25,000 bytes. UFM
presently works only with the ECS-produced .met file.
What are G-Rings and G-Polygons?
A G-Ring (or Geometry Ring) is a closed sequence of ordered pairs of coordinates of latitude
and longitude in floating point that define the boundary of the area. Latitude and longitude are
specified in decimal degrees with north latitudes positive and south negative, east longitude
positive and west negative. The first and last points in the set of coordinates must be the same
(Figure 31).
The outer G-Ring describes the outside edge of the G-Polygon (the full coverage extent). Inner
G-Rings describe any holes that may occur in the G-Polygon (areas of missing coverage within
the outer ring). The GPolygon class contains the G-Ring attribute for the exclusion ring flag,
which is added to each polygon definition to describe whether the polygon is an inner or outer
ring of coverage.
77