Transcript Map Reproduction

MAP
REPRODUCTION
Cartographic Design for GIS (Geog. 340)
Prof. Hugh Howard
American River College
MAP REPRODUCTION
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The printing of a map, or the electronic
duplication of a map
– Print reproduction refers to the physical
printing of a map using inks on paper
– Electronic reproduction refers to the
duplication of a map in digital form
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I will focus on print reproduction
PLANNING AHEAD
PLANNING AHEAD
PLANNING AHEAD
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The following questions need to be
answered early in the design process
– Who is the intended audience, and what is
the purpose of the map?
– What is your budget?
– When is your deadline?
– What material will be used?
– Will it be printed in full color or gray tones?
PLANNING AHEAD
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What size will it be?
How many copies are required?
Will it be folded? What will the pattern be?
What level of print or display quality is
acceptable?
– Will you copyright the
map? Will the map
infringe on an existing
copyright?
MAP EDITING
MAP EDITING
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The critical evaluation and correction of
every aspect of a map
– Begins the first time the cartographer
views the map in its early stages, and
culminates just before reproduction begins
MAP EDITING
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Questions that should be addressed
when editing:
– Map design: Does the design
appropriately serve the map user? Does it
communicate effectively?
– Completeness: Are any features, map
elements, or type labels missing?
– Accuracy: Are features, map elements,
and type labels correctly placed? Are
words and numbers correct?
MAP EDITING
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Cartographers who edit their own maps
face over-familiarity and fatigue
– Have a separate individual edit the map
– Edit with “fresh eyes,” at the beginning of
a work session
– Edit large maps in sections
– View maps upside-down or sideways
– Edit after several days of separation from
a map
– Read type out loud
RASTER IMAGE
PROCESSING for PRINT
REPRODUCTION
RASTER IMAGE PROCESSING
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The conversion of a digital map into a
raster image that can be processed
directly by a raster-based printing
device
RASTER IMAGE PROCESSING
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Printing the digital map
SCREENING for PRINT
REPRODUCTION
SCREENING
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A technique that makes colors appear
lighter
– Involves reducing the amount of ink or
toner applied to the print medium
– Used to create tints of a base color, and to
represent continuous tone surfaces
SCREENING
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Two categories of screening
– Halftone
– Stochastic
SCREENING
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Halftone screening
– Used in most print reproduction methods
with the exception of ink-jet printing
– Ink or toner is applied in a pattern of
equally spaced dots of variable size
Amplitude
Modulation
(A.M.)
SCREENING
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Halftone screening
– Helped define the pop art movement…
SCREENING
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Stochastic screening
– Used primarily with ink-jet printing
– Ink or toner is applied in a pattern of very
small, pseudo randomly spaced dots of
uniform size
Frequency
Modulation
(F.M.)
ASPECTS of
COLOR PRINTING
COLOR PRINTING
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Process colors
– CMYK (subtractive primaries + black)
– Mixed on the page by applying them, in
sequence, to the same area
Cyan
+ Black
Magenta
Yellow
COLOR PRINTING
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Process colors (cont.)
– Semi-opaque, or translucent, allowing
them to combine on the page
– Together with screening, allow for the
creation of a wide variety of colors
– Used in four-color process printing
COLOR PRINTING
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Process colors (cont.)
– When mixed on the page, tints of each
base color are represented by halftone
patterns, each with a unique screen angle
Rosette
Pattern
COLOR PRINTING
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Spot colors
– Opaque inks that are premixed before
they reach the printing device
– Tints can be created through screening
– Exact color matches are easier to achieve
because they do not rely on the printing
device for mixing
HIGH VOLUME PRINT
REPRODUCTION
HIGH VOLUME PRINT REPRO.
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When large numbers of maps are
required, issues of cost and time
become critical
– Methods for low-volume print reproduction
such as laser and ink-jet printing become
too costly or time-consuming
– High-volume reproduction is dominated by
a single method: Offset Lithography
HIGH VOLUME PRINT REPRO.
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Offset Lithography
– Lithography is a printing process in which
ink sticks only to certain areas of a surface
– Virtually all mass-produced maps are the
result of offset lithography
– Characterized by excellent print quality
and high printing speed
HIGH VOLUME PRINT REPRO.
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Offset Lithography (cont.)
– Provides a significant decrease in the cost
per unit as the number of copies increases
– Performed on an offset lithographic
printing press
HIGH VOLUME PRINT REPRO.
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The pre-press phase
– Consists of various technologies and
procedures that make offset lithographic
printing possible
– Printing plates are produced
– Proofs are produced
HIGH VOLUME PRINT REPRO.
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Printing plate
– A sheet of aluminum that is ultimately
mounted on a roller on an offset press
– Receives a positive, latent (invisible)
image that ink will stick to
HIGH VOLUME PRINT REPRO.
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Printing plate (cont.)
– One is created for each color
– Mounted on an offset press, washed with
ink, and used to transfer an image onto
the print medium
Traditionally
created from film
negatives
Replaced by
Computer-To-Plate
(CTP) technology
HIGH VOLUME PRINT REPRO.
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Proof
– A representation of what the final,
reproduced map will look like
– An essential component of the prepress
phase
– Used in conjunction with editing to ensure
that your map will be reproduced just as
you intend
HIGH VOLUME PRINT REPRO.
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Proof (cont.)
– Various levels of quality/cost
HIGH VOLUME PRINT REPRO.
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File formats for pre-press
– A digital map can be delivered to the
service bureau in a variety of formats
– In the native format of the application
software that created it (.MXD, .AI)
– In a page description language
(Postscript)
– In a portable document format (EPS, PDF)
HIGH VOLUME PRINT REPRO.
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Offset Lithographic Printing
– The offset press has one or more printing
units that transfer ink to the print medium
– Each printing unit is capable of printing
one base color
HIGH VOLUME PRINT REPRO.
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Offset Lithographic Printing (cont.)
– The image is transferred from the printing
plate to the blanket cylinder, which then
transfers the image onto the print medium
HIGH VOLUME PRINT REPRO.
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Offset Lithographic Printing (cont.)
– Multicolor print jobs employ multiple
printing units, one for each base color
– The print medium receives a different
color ink from each printing unit
MAP
REPRODUCTION
Cartographic Design for GIS (Geog. 340)
Prof. Hugh Howard
American River College