PLOTTER AND PRINTER REQUIREMENTS TO PORTRAY GEOGRAPHIC INFORMATION SYSTEM
VISUALIZATIONS
Gregory J.
U. S. Geological
Wisconsin USA
Madison,
Allord
Survey
KEY WORDS: Cartography, Graphics, Mapping, Plotter, Technology, Visualization
ABSTRACT: Most graphics for visualization of data from Geographic Information Systems (GIS) are
still plotted or imaged on paper and film media. These images, often in color, are required to satisfy
needs varying from intermediate plots for data verification and review to printed final documents
distributed to thousands of customers. These documents must accurately show GIS data. Visualizations
are also required to aid data checking and verification, intermediate and final reviews, preliminary
cartographic design checking, and as final cartographic products. Many GIS sites use plotters selected
and installed on the basis of technology that is readily available rather than devices installed explicitly
to support the data used in the GIS or to correctly convey the design and colors of thematic maps.
However, the characteristics of plotters, printers, imagesetters, and offset lithography must be
considered when producing a product from a GIS data set and the selected hardware also must support
the defined, known data standards in the GIS. This paper presents a discussion of the resolution
thresholds and characteristics of devices necessary to visualize GIS data.
U. S. Geological Survey plotted or printed maps
and images are often the visual culmination of
hydrologic projects using Geographic Information
System (GIS), satellite interpretation, or
photogrammetry technologies. Sooner or later in a
project, plotters, imagesetters, or printers often
are used in support of a GIS project. Paper and
film products produced by a GIS and other digital
imaging systems must meet several requirements
to properly support the visualizations of data.
These factors based on the resolution and spatial
accuracy of the data or imagery include:
dimensional stability; plotter accuracy;
accessibility; color integrity; plot generation
speed, accurate thematic design rendition;
customer requirements; timeliness; ease of use;
product life cycle; and plotting device reliability.
There is no great difference in the concept of
preparing data for visualization on a plotter
versus printing the final data. The concepts for
both are comparable but each method can serve to
support different project needs. The goal is
obtaining the best possible product to meet those
needs.
The cartography technology assessment project of
the U. S. Geological Survey, Office of Water
Information supports assessment and innovation of
new technologies applied to bridge spatial and
74
hydrologic analysis with thematic cartography and
information distribution. One purpose of this
project is to assess and document the required
capability and precision of a variety of plotters
and imaging systems necessary to maintain the
data integrity and accuracy of hydrologic study
data, including data products such as thematic
maps and raster images. The plotter and imaging
accuracy includes positional accuracy as well as
gray scale and color capabilities.
The project assesses and documents factors, in
addition to the required spatial quality, that
influence the selection of plotting or printing
technologies used in typical GIS projects.
Examples of other factors that affect plotter or
imagesetter selection include: finishing and final
size of plots; performance and reliability; plotter
speed and sustained plot rate; support for specific
substrates of plotter media; and cost per plot. The
project currently is compiling comparisons of a
variety of plotters and printers to more fully
define the ability of devices to properly maintain
the original thematic cartographic design or
spatial data details, especially for raster data.
The range of colors and resolutions affect the
design choices for thematic cartography. The
range of colors available on higher resolution, 24-
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