UNIT 48: DESIGNING PRODUCTS FOR PRINTING

Written by Kevin M. Curtin, NCGIA, Department of Geography, University of California Santa Barbara

Context

Printed geographic products can take one of several forms. Among these are tables, charts, surfaces, and maps. Each of these formats has unique characteristics for displaying spatial information, and specific requirements for doing so effectively.

The printed map is one of the most widely used tools for the presentation of geographic information. The proper design insures that a map will effectively communicate the results of a geographic analysis or description. Poor design will cause the map to become - at best - an ineffective tool for the transfer of information, and - at worst - a source of misinformation.

The elements of proper map design can be roughly broken into two groups - 1) the features, symbols, and text to be printed on the map (and their relative placement) and 2) the process of choosing the data to be placed on the map given the information to be conveyed and the audience for which it is intended. Issues of cartographic tradition, common knowledge of symbols, and the limits of artistic license must be taken into consideration when a cartographer chooses the elements that will comprise a given map. The proper design for other types of geographic information (charts, graphs, etc.) can be considered as a sub-set of proper map design, and will be discussed as such.

While no single map can be considered "typical" of more than a small subset of maps, the following Example Application will demonstrate the process of selecting the proper map elements. Moreover, it will illustrate a method of arranging the map elements in such a way as to effectively communicate the intended information through the medium of a printed product.

Example Application

CENSUS TRACTS CONTAINING INCIDENTS OF CANCER (AND ASSOCIATED DEMOGRAPHIC DATA)
Census Tract	Area (Sq. miles)	Population (1993)	Households (1993)	Firms Using Toxin
021304	3.029	8093	3800	6
050705	28.867	7475	2471	8
110500	54.895	10449	3701	10
110200	63.410	2493	904	11
050704	21.651	8256	2647	12
110400	13.414	4739	1782	10
110600	60.831	6319	2221	24
060100	37.950	7409	2521	7
110800	50.213	4334	1529	26
100100	47.556	6451	2236	27
023407	24.295	11979	4502	9
100200	92.717	5829	2044	28
040402	15.876	10161	3375	7
060401	21.050	8010	2617	10
100300	13.446	5239	2086	30
070102	13.757	7273	2462	11
100900	36.140	6122	2175	12
060402	24.221	12050	3886	13
070201	19.907	5229	1829	14
070103	26.531	13839	4966	14
070202	21.145	2204	774	15
040604	5.150	9331	3664	2
100800	49.186	3230	1136	23
070203	35.639	3136	1084	13
070302	29.637	9936	3473	12
040606	9.656	1473	273	20
070402	34.237	2030	710	21
150100	88.644	4233	1565	22
150200	38.256	6702	2302	23

Learning Outcomes

The following list describes the expected skills which students should master for each level of training, i.e. Awareness/Competency/Mastery.

Preparatory Units

Recommended:

Awareness

Required Map Elements:

• Title: A map, like any other document, must be introduced to the reader through the use of a brief, descriptive title. The title should be written in a larger font than any other supporting map text or annotation. It may be in bold type for greater emphasis. The title need not be placed at the top of the map, especially if doing so would detract from the importance of the map features themselves. It is often useful to include the location of the map elements in the title. Never use abbreviations or unspecified acronyms in the title.
• Scale: Many GIS applications are considered to be scaleless due to the ability to rapidly and interactively change scale on screen, reducing or enlarging features as appropriate (Clarke 1997). This is NOT true for printed maps. In order to be usable, the map must state the scale at which its features are drawn. The map scale shows the relationship between distances on the map and distances in the real world. There are several ways to represent the scale of a map including:

Competency

In order to possess skill in map-making more is required than a simple awareness of the elements which comprise a complete map. A competent cartographer must be capable of selecting the appropriate map type for the data to be presented and printing the map on a range of media and at a number of different scales.

Map Types: Since there are many ways to display information on a map, the cartographer has a responsibility to choose the method most suitable for a particular set of geographic data. Some of the more common general types of maps and their characteristics are:

• Reference Maps - (or general purpose maps) are collections of point, line, or polygon features. These are generally designed to convey information about the absolute location of objects on the surface of the earth, and are used for navigation and as a reference for feature location. Road maps fall into this category as do most boundary maps which show political features (states, cities, counties, etc.), and topographic maps which show the delineation of physical features on the landscape.
• Dot Maps - use dots to show the distribution and density of some phenomenon over an area. Often each dot will represent some number of entities. For example, each dot may represent 100 people in a given county, or a dot may stand for 10 bushels per acre of some crop grown in a state. The dots are commonly assigned simply to one polygonal feature and should not be considered as point locations of the phenomenon.
• Picture Symbol Maps - are similar to dot maps, in that they locate a phenomenon of the surface of the Earth. However, the symbol is representative of the phenomenon being described rather than a generic dot. Examples are pictures of busses to locate bus stations or stops, pictures of male or female silhouettes to show the locations of rest-rooms, or pictures of baseballs to located cities with minor league baseball teams.
• Graduated Symbol Maps - are dot or other symbol maps with variation in symbol dimension based on the value of the feature at a particular location. Generally, the larger the symbol the larger the value at that location.
• Network Maps - display an integrated system of linear features. The intersections are well defined and the potential routes along the network system are often identified. Maps of transportation systems (trains, subways, bus routes, etc.) and other means of delivery are network maps.

• Choropleth Maps - display values of data in polygonal areas through the use of color. There are many variations of choropleth maps including:
• classed choropleth - data are classed and areas are shaded or colored differently according to their class value
• unclassed choropleth - differences in data values are shown using a continuous variation in tone or color rather than the steps that result from classes
• area qualitative map - a color is assigned to a value, but the range of colors does not imply an association or ranking among different values.
• Stepped Statistical Surface Maps - are representations of polygons as volumes with the height of the volume corresponding to the value associated with the polygon.
• Isoline Maps - utilize the intervals between lines joining points of equal value to represent areas of varying value. These intervals may be shaded, colored, or identified with a text value. If the color scheme is used to illustrate variation in data values the isoline map is known as a Hypsometric Map. Examples include maps of temperature or other climate factors, contour maps, and maps displaying travel times from a given point.

There are also a number of ways of displaying 3-dimensional geographic data (gridded fishnet, realistic perspective, simulated hill shading) and these require an even greater amount of care in their use. For example, the scale of a map shown in 3-dimensions is very different at the foreground of the image than it is at the background. You may want to consider 3-dimensional displays of geographic data as "graphics" rather than "maps" and plan your printed product accordingly.

Production Cartography: When the map type has been chosen, the cartographer must use their knowledge of the required map elements to output a printed product. Production Cartography requires that the following steps be completed:

• Compilation - the process of assembling the diverse elements of the map that will be included in the final product. This includes the source data for the map features, any thematic data to be associated with the features, and the construction of the required map elements (scale, title, legend, etc.).
• Layout - the collection of objects from the compilation process must be arranged on a layout. This can be physically or with the assistance of a mapping software package. Based on an initial layout, additions, deletions, or other edits can be made to the elements of the map.
• Map Production - the actual process of outputting a map on one of many possible devices. The output may go to a computer screen, a pen plotter, a hydrostatic plotter, an ink jet device, or one of many possible hardware products. The map may even be stored in its finished form in a computer file waiting to be reproduced in some other medium at an appropriate time.
• Map Reproduction - The number of copies of the map must be considered in order to choose the appropriate medium, output device, and method for map reproduction. Map reproduction methods designed for a small number of copies are not necessarily the correct choice for a map which much be reproduced many thousands of times. The cartographer must assess the extent of the maps audience in order to choose the most cost efficient map reproduction method.

Mastery

When a cartographer is aware of the elements that are required to make an acceptable map, and is competent to choose the proper map type given the data to be presented, the process of designing maps can be mastered. Map design requires

1. an understanding of the use of color and pattern in mapping applications
2. a familiarity with cartographic tradition in the use of symbols
3. the development of a style of mapping which is efficient

Color and Pattern: Choropleth maps use color to differentiate between values associated with map features. However, the colors employed must be carefully considered. Opposing colors should only be used for distinguishing between opposing data values on the same map. Examples include values below and above a given temperature, values for profit and loss, or two-party election results. In other cases variation in shade or tone for a single color is appropriate. The use of pattern is similarly constrained. Use pattern sparingly as it can be confusing to a map reader. Refrain from combining pattern symbols - use color and pattern or some other visual variable instead.

Traditional Cartographic Use of Symbols: With few exceptions, it is advisable to follow cartographic convention when mapping, that is, color water blue, forest green, contours brown, etc. These conventions have been accepted by the very large majority of map readers over their lifetimes. By straying from these traditional methods of symbolization you are risking that people will misinterpret your map.

Mapping Style: Lastly, the cartographer must implement the awareness of map elements and the ability to competently design and produce maps which show the mastery of color, pattern and traditional use of cartographic symbols. By doing so the cartographer will develop an individual style. This style will likely grow and mature over time as the cartographer experiments with variations on the mapping themes. This style will incorporate the cartographers knowledge with artistic skill to produce exceptional maps.

Follow-up Units

Resources

The following is a short list of world wide web addresses for sites that engage in mapping activities or cartographic education. This is a very limited list, many more sites exist.