Geoscience Reference
In-Depth Information
•
PostScript
(PS) and
Encapsulated PostScript
(EPS) - h e PS format was
developed by John Warnock at PARC, the Xerox research institute.
Warnock was also co-founder of Adobe Systems, where the EPS format
was created. h e PostScript vector format would never have become an
industry standard without Apple Computers. In 1985 Apple needed a
typesetter-quality controller for the new Apple LaserWriter printer and
the Macintosh operating system and adopted the PostScript format. h e
third partner in the history of PostScript was the company Aldus, the
developer of the sot ware PageMaker and now a part of Adobe Systems.
h e combination of Aldus PageMaker sot ware, the PS format and the
Apple LaserWriter printer led to the creation of Desktop Publishing.
h e EPS format was then developed by Adobe Systems as a standard i le
format for importing and exporting PS i les. Whereas a PS i le is generally
a single-page format containing either an illustration or a text, the purpose
of an EPS i le is to also allow the inclusion of other pages, i.e., a i le that
can contain any combination of text, graphics and images (http://www.
adobe.com).
• In 1986 the
Joint Photographic Experts Group
(JPEG) was founded for
the purpose of developing various standards for image compression.
Although JPEG stands for the committee, it is now widely used as the
name for an image compression and a i le format. h is compression
involves grouping pixel values into 8-by-8 blocks and transforming each
block with a discrete cosine transform. As a result, all unnecessary high-
frequency information is deleted, which makes this compression method
irreversible. h e advantage of the JPEG format is the availability of a
three-channel, 24-bit, true color version. h is allows images with smooth
color transitions to be stored. h e new JPEG-2000 format uses a wavelet
transform instead of the cosine transform (Section 5.8) (http://www.jpeg.
org).
•
Portable Document Format
(PDF) - h e PDF designed by Adobe Systems
is now a true self-contained cross-platform document. PDF i les contain
the complete formatting of vector illustrations, raster images and text, or
a combination of all these, including all necessary fonts. h ese i les are
highly compressed, allowing a fast internet download. Adobe Systems
provides the free-of-charge Acrobat Reader for all computer platforms to
read PDF i les (http://www.adobe.com).
