When Bill Bunge mapped out the locations of car/pedestrian collisions in Detroit (Detroit Geographical Expedition, 1968) he and the map were advocating a way of thinking about what was happening to the black community in Detroit – and advocating for change.

All maps advocate.

To advocate means to “to speak or write in favor of; support or urge by argument; recommend publicly.” The word derives from the Latin advocate: “to call to one’s aid.”

What map does not advocate, or argue for something? We are always calling maps to our aid.

Three free books on maps and advocacy have been made available for download recently, and are worth a look.

•••••

Two New PDF Books [added June 6 2009]:

Good Practices in Participatory Mapping (2mb PDF here, 2009). Published by International Fund for Agricultural Development.

A review of participatory mapping methods.

This report will review existing knowledge related to participatory mapping and recent developments. Specifically:

• Section 1 will define the main features of participatory mapping;
• Section 2 will discuss key applications of participatory mapping;
• Section 3 will present specific tools used in participatory mapping, including their strengths and weaknesses;
• Section 4 will identify good practices and explore the significance of process in participatory mapping initiatives.

•••••

Toolbox & Manual: Mapping the Vulnerability of Communities (4.4mb PDF English version here, Portuguese version aqui, 2008). Published by Salzburg University Centre for Geoinformatics.

A overview of concepts and methods for community mapping, focused on vulnerability.

Within the research and project context it is aimed to provide the local communities with appropriate maps of their communities. The maps should enhance planning and decision making processes within the communities in regard to reduce local vulnerabilities and allow appropriate planning of disaster response measures. It is the first time in Mozambique that maps have been produced with such an accuracy (high resolution data) and for disaster risk management through the integration of participatory practices.

•••••

•••••

Visualizing Information for Advocacy: an Introduction to Information Design (7mb PDF here, January 2008). Published by Tactical Technology Collective.

Succinct, well-designed, with many good examples of maps and information graphics for advocacy.

…a manual aimed at helping NGOs and advocates strengthen their campaigns and projects through communicating vital information with greater impact. This project aims to raise awareness, introduce concepts, and promote good practice in information design – a powerful tool for advocacy, outreach, research, organization and education.

•••••

Maps for Advocacy: An Introduction to Geographic Mapping Techniques (3mb PDF here, September 2008). Published by Tactical Technology Collective.

A great overview of maps and advocacy with many examples and resources.

The booklet is an effective guide to using maps in advocacy. The mapping process for advocacy is explained vividly through case studies, descriptions of procedures and methods, a review of data sources as well as a glossary of mapping terminology. Scattered through the booklet are links to websites which afford a glance at a few prolific mapping efforts.

•••••

Field Guide for Humanitarian Mapping (3.2mb PDF here, March 2009). Published by MapAction.

A textbook for using maps and GIS in humanitarian work.  The Guide provides detailed information on data collection (GPS) and the use of Google Earth and MapWindow (free mapping software).

The guide was written to meet the need for practical, step-by-step advice for aid workers who wish to use free and open-source resources to produce maps both at field and headquarters levels. The first edition contains an introduction to the topic of GIS, followed by chapters focused on the use of two recommended free software tools: Google Earth, and MapWindow. However much of the guidance is also relevant for users of other software.

•••••

Some related resources:

• the Tutor/Mentor Collection’s GIS and Mapping Resources Page.
• slides & text from Erik Hersman’s Activist Mapping presentation at Where 2.0.
• the Atlas of Radical Cartography.
• Counter-Cartographies Collective & 3C’s Blog.
• An Introduction to Critical Cartography (176k PDF) by Jeremy Crampton & John Krygier (2006)
  
• “Protest Maps” (292k PDF) by Denis Wood & John Krygier (2009).
• Mapping: A Critical Introduction to Cartography & GIS by Jeremy Crampton (2009).

This manual establishes the design, weights, and gauges of symbols, and the type styles and sizes to be used in compiling and drafting standard topographic maps prepared by the Army Map Service for publication at the scale of 1:1,000,000.

During the compilation stages, strict adherence to symbol specifications shall not be required.  Line weights and gauges may be varied twenty percent (20%), plus or minus, from prescribed specifications.

In using the symbols specified for drafting, strict adherence to the prescribed weights and gauges must be maintained.

The examples below are map symbols for permanent ice and snow features.

The 1953 Army Map Service guide Symbols for Small Scale Maps details map symbol specifications for compiled maps (left, below) and drafted maps (right, below). Compiled maps are the initial draft of a map, where diverse sources of information are drawn together.  Using the compiled map, a cartographic draftsman creates the final, drafted map, suitable for printing.

The map symbol specifications include detailed symbol dimensions:

Specifications for glaciers:

Specifications for ice cliffs:

Specifications for the limits of icefields or snowfields:

The entire page 22 of the Army Map Service Symbols for Small Scale Maps, including specifications for permanent snow and ice features is linked below:

Denis Wood & John Fels’ new book The Natures of Maps is available now from the University of Chicago Press and many other sources. The lowest price I can find at this time is $29 (at Buy.com). Denis is, of course, co-author of the Making Maps book.

The book is big – almost a foot square – with color maps on almost every page.  The book had a harrowing path to publication.  Originally under contract to ESRI Press, the book was in final galleys (ready to print but for a handful of edits) when ESRI Press decided to cancel it and a dozen other books in process.  Given the expense of producing the book (and the cost of reproduction rights to the illustrations) this seemed to be a peculiar business decision.  The University of Chicago Press subsequently acquired the book, more or less ready to print.

Here’s an “editorial” blurb I wrote for the book:

If Wood & Fels’ The Power of Maps showed that maps were powerful, The Natures of Maps reveals the source of that power. The Natures of Maps is about a simple but profound idea: maps are propositions, maps are arguments. The book confronts nature on maps – nature as threatened, nature as threatening, nature as grandeur, cornucopia, possessable, as a system, mystery, and park – with intense slow readings of exemplary historical and contemporary maps, which populate this full color, beautifully illustrated and designed book.

The careful interrogation of maps reveals that far from passively reflecting nature, they instead make sustained, carefully crafted, and precise arguments about nature. The Natures of Maps shows how maps establish nature, and how we establish maps. The power of maps extends not only from their ability to express the complexities of the natural world in an efficient and engaging manner, but in their ability to mask that they are an argument, a proposal about what they show.

The implications of the arguments in The Natures of Maps are significant, empowering map users and makers. The Natures of Maps shows that neither map users or map creators are passive, merely accepting or purveying reality; they are, instead, actively engaged in a vital process of shaping our understanding of nature in all its complexity. Map users have a critical responsibility, the power to accept, reject, or counter-argue with the maps they encounter. Map creators have creative responsibility, the power to build and finesse their arguments, marshalling data and design for broader goals of understanding and communicating truths about the world. Rethinking how maps work in terms of propositional logic, with its 2000-year history and vast methodological and theoretical foundation, promises to be one of the most profound advances in cartographic theory in decades, and The Natures of Maps shows the way in a captivating manner.

Considering maps from the perspective of propositional logic provides a rigorous foundation for a theory of the map that transcends disciplinary boundaries. Scholars from the humanities, social sciences, and natural sciences will find Wood and Fels’ The Natures of Maps intellectually sound, methodologically useful, and deeply engaging. But the beauty of The Natures of Maps is that it is not merely an academic book. Wood and Fels’ The Natures of Maps is a powerful, beautifully illustrated and engaged argument about maps as arguments that will appeal to map lovers, map makers, map users, and map scholars.

Erwin Raisz is among the most creative cartographers of the 20th century, known in particular for his maps of landforms.

In 1931 Raisz outlined and illustrated the methods behind his landform maps, in an article in the Geographical Review (Vol. 21, No. 2, April 1931). Excerpts from the text and graphics in the article are included below.

Raisz’s approach is to create complex pictorial map symbols for specific landform types. Each specific application, of course, would have to modify the symbols to fit the configuration of particular landforms.

One of the limitations of Raisz’s work is that it is so personal and idiosyncratic that it virtually defies automation or application in the realm of computer mapping. Thus digital cartography has, in some cases, limited the kind of maps we can produce.

Raisz writes:

There is one problem in cartography which has not yet been solved: the depiction of the scenery of large areas on small-scale maps.

Most of our school maps show contour lines with or without color tints. Excellent as this method is on detailed topographic sheets … it fails when it has to be generalized for a small-scale map of a large area. Nor does the other common method, hachuring, serve better.

For the study of settlement, land utilization, or any other aspect of man’s occupation of the earth it is more important to have information about the ruggedness, trend, and character of mountains, ridges, plains, plateaus, canyons, and so on-in a word, the physiography of the region.

Our purpose here is to describe and define more closely a method already, in use, what we may call the physiographic method of showing scenery. This method is an outgrowth of the block diagram. [T]he method was fully developed by William Morris Davis. Professor Davis has used block diagrams more to illustrate physiographic principles than to represent actual scenery.

Professor A. K. Lobeck’s Physiographic Diagram of the United States and the one of Europe do away entirely with the block form, and the physiographic symbols are systematically applied to the vertical map. His book Block Diagrams is the most extended treatise on the subject.

It is probable that the mathematically-minded cartographer will abhor this method. It goes back to the primitive conceptions of the early maps, showing mountains obliquely on a map where everything should be seen vertically. We cannot measure off elevation or the angle of slope. Nevertheless, this method is based on as firm a scientific principle as a contour or hachure map: the underlying science is not mathematics but physiography.

If we regard the physiographic map as a systematic application of a set of symbols instead of a bird’s-eye view of a region, we do not violate cartographic principles even though the symbols are derived from oblique views instead of vertical views. It may be observed that our present swamp symbols are derived from a side view of water plants.

••••••

Landform map symbols include: plains (sand & gravel, semiarid, grassland, savannah, forest, needle forest, forest swamp, swamp, tidal marsh, cultivated land), coastal plain, flood plain, alluvial fans, conoplain, cuesta land, plateau (subdued, young, dissected), folded mountains, dome mountains, block mountains, complex mountains (high, glaciated, medium, low, rejuvenated), peneplane, lava plateau (young, dissected), volcanoes, limestone region (with sinkholes, dissected, karst, tropical, mogotes), coral reefs, sand dunes, desert of gravel (serir), deflated stone surfaces (hamada), clay (takyr), loess region, glacial moraine, kames, drumlin region, fjords, glaciers, shoreline (sand, gravel, cliffed), and elevated shorelines & terraces.

Wells

Springs

Successful, Unsuccessful

Nonmineral, Mineral

Nonmineral, Mineral, Artesian, Gravity, Artesian, Gravity

Rise, No Rise, Rise, No rise, Cold, Warm, Cold, Cold, Warm, Cold

Flowing, Nonflowing, Flowing, Nonflowing

Those are all the wells and springs…

In general there has been no attempt at uniformity of practice in the delineation on maps of underground water features or of wells or springs… …it now appears desirable that a concerted movement be made to develop a uniform system of symbols for use on maps.

The number of symbols devised should be sufficient for the representation of all features which it is desirable to show. If wholly arbitrary devices are used, confusion will result whenever a considerable number are used simultaneously, but this difficulty will be largely avoided if the system adopted is based on a few suggestive forms grouped according to easily remembered principles.

The principles to be considered in devising a system of well and spring symbols for underground water maps are (1) simplicity, (2) clearness, (3) ease of making, and (4) suggestiveness. Failure to answer these various requirements ruled out many of the arbitrary systems used in the past…

It is believed that a system of symbols can be most logically developed if a single arbitrary device is taken as a base. In common practice a circle is most often used for a well, while more or less closely allied devices are used for springs. Inasmuch as both wells and springs are ordinarily approximately circular, this device, which seems to have both the required simplicity and suggestiveness, is proposed.

Words of map symbolization wisdom from “Representation of Wells and Springs on Maps” by Myron Fuller in Water-Supply and Irrigation Paper No. 160, U.S. Geological Survey (1906).

A cartogram varies the size of geographic areas based on the data values associated with each area. Typical cartograms scale geographic areas to population, GNP, electoral votes, etc.

This “apportionment map,” as creator William B. Bailey (Professor of Political Economy, Yale University) calls it, scales the size of U.S. states to the size of their population (in 1910). Note that New York has colonized much of the upper Midwest.

The map, published April 6, 1911 in The Independent is one of the earliest cartograms I have seen.

Apportionment means “allotment in proper shares.” Thus, each state size is allotted based on population, not actual geographical area. Is a curious term to use, possibly more meaningful than the somewhat vague term “cartogram” (a “map diagram”).

Bailey writes:

The map shown on this page is drawn on the principle that the population is evenly distributed thruout the whole United States, and that the area of the States varies directly with their population. With the map constructed on this principle some curious changes become apparent. On the ordinary map the four States, Montana, Wyoming, Colorado, and New Mexico, together with the seven States which lie to the west of them, comprise more than one-third of the territory of the United States, and the area of each one of them is considerably larger than that of New York State; yet the population of New York State alone is nearly one-fourth larger than the combined population of these eleven Western States. In fact, the entire territory to the west of the Mississippi River contains only about 5 per cent. more people than are to be found in the New England States, together with New York, New Jersey, and Pennsylvania. Yet the territory at present covered by these nine Eastern States is only about two-thirds as large as the State of Texas. If we should add to these nine Eastern States the population of Ohio, the total would be greater by about three millions than the entire population west of the Mississippi. The State of Rhode Island, hardly visible to the naked eye on the ordinary map, now becomes almost as large as the territory of Utah and Arizona combined.

Were Texas as densely populated as is the State of Rhode Island, it would contain a population of nearly eighty-five millions, leaving only six millions of our people to be scattered thruout the rest of the country. Were the population of the United Stats as a whole as dense of that of Rhode Island this country would have more than a billion inhabitants.

Cartograms can show derived data (suicide rate in U.S. states, left) or totals (electoral votes in U.S. states, right):

Cartograms can be contiguous or non-contiguous:

Illustrations taken from Making Maps book, p. 218-19.

According to Waldo Tobler (PDF article: “Thirty Five Years of Computer Cartograms”) the term cartogram has been used since at least 1851, but it seems like the kind of cartograms shown above are rare until the first few decades of the 20th century.

Confusingly, the term cartogram was commonly used to describe various kinds of graphs and statistical maps (also called thematic maps), making it difficult to trace the genealogy of the modern cartogram.

A “cartogram” (bar graph) from Vocational Education by John Morris Gillette (1910):

A “cartogram” (graduated circle map) from Junior High School Mathematics by George Wentworth et al., (1917):

A “cartogram” from the Foreign Missions Year Book of North America for 1919:

A “cartogram” (choropleth map) from Studies in Occupations (1921):

A “cartogram” from Isaiah Bowman’s The New World: Problems in Political Geography (1921):

••••••

Sara Fabrikant offers cartogram information, examples, and resources focused on the 2004 U.S. election. She includes references. The prolific Waldo Tobler has a half dozen of his cartogram articles available as PDFs.

Make your own cartograms with MAPresso and Frank Hardesty’s Cartogram Generator.

Cartogram Central has some interesting links, but has not been updated since 2002. Worldmapper has a passel of global cartograms.

Map of New York City, Showing the Distribution of the Principal Nationalities by Sanitary Districts published in Harper’s Weekly (June 1, 1894) using 1890 U.S. Census data.

This map looks great, revealing a substantial amount of information with its intense, juxtaposed patterns.

The textures on the map show the relative amounts of different nationalities (qualitative data) in each of the areas (sanitary districts) on the map:

The map shows if a district has more or less diversity (more or fewer lines of different textures), the relative proportions of different nationalities, the nationalities themselves, and, at a broader scale, the districts that are similar or differ in their nationality constitution. Because of the careful rotation of the lines of textures, the different sanitary districts can also be distinguished from each other.

To quote the text which accompanies the maps (and explains the methodology of the map):

The census of 1890 obtained the nationality of the residents of each sanitary district by descent from the mother. The table in which this appears was made the basis of the nationality map. As a basis it will appear fair enough when it is considered that at the time of the census over seventy-six percent of the white population in the city had foreign-born mothers, and over forty per cent. were foreign-born themselves. So the latter certainly, and probably a majority of the thirty-six percent. of native-born of foreign mothers, would show the traits of their maternal nationality. All the nationalities given in the table are not plotted. The Scotch, English, Welsh, Scandinavian, and Canadians have not collected in colonies, but are scattered over the city. These, being in small numbers, and perhaps less foreign than the others, were disregarded. They appear in the unclassified [category] in the diagram at the foot of the map. Of the nationalities represented only those making up two-thirds of the population of any district have been plotted. This rule was adopted to bring out in clearer contrast those that do exist to a greater extent. The nationalities are represented by bands conventionally marked. The breadth of a band in any district bears the same relation to the sum of the breadths of the different bands in that district as the number of the nationality it represents bears to the two-thirds of the population in that district. Sanitary district S of the Twelfth Ward and the Twenty-third Ward are not touched. These were left blank because the method of representing nationalities gives an erroneous idea in regard to the density of population. These thinly populated districts where natives preponderate slightly would appear as native settlements. These, of course, they are, but not like other parts of the city, for they are suburban.

A map of population density (shown below) accompanies the Nationalities map, using increasingly dense textures to represent quantitative population differences:

The Nationalities map illustrates (in 1894) Edward Tufte’s demand for maps (and other information graphics) that reveal the multivariate and complex. This is a map to spend time with, not because it is poorly designed, but because it contains a substantial amount of information.

The New York City Principal Nationalities Map in its entirety (1890 data; rotated to fit your screen):

The New York City Population Density Map (1890 data):

The map pair, side by side for comparison (as originally published):

The map was created by Frederick E. Pierce for the Tenement-House Committee, one of the progressive organizations working against urban slums and blight in the late 19th and early 20th centuries. The text notes that the original map was in color, but was redrawn for publication in monochrome.

•••••

Texture is usually included as one of the cartographic visual variables. The visual variables, which provide a guide for matching visual marks to data characteristics (such as qualitative vs. quantitative data), are attributed to French semiotician Jacques Bertin.

I discuss and illustrate, with contrasting good/poor maps, the basic visual variables (shape, size, color hue, color value, color intensity, and texture) in chapter 9 (excerpt here) of Making Maps.

Texture can be difficult to work with as it can imply either qualitative or quantitative differences, and has a tendency to vibrate.

Back in the day, Zip-a-Tone (a brand of screentone) was used to create texture and gray-scale patterns on maps (and comics). Printed on a thin, clear material with adhesive backing, many a cartographer spent hours searching through sheets of Zip-a-Tone, cutting it to size, and adhering it to different areas on the map. Now diverse pattern fills are available in GIS and graphic design software (Illustrator, Corel).

The problem is that while generic textures – Zip-a-Tone or digital – could be used as “area fills” for a contemporary map of nationalities (like the 1890 Nationalities Map), one would still have to engage in the painstaking task of calculating ratios and creating appropriate areas for the different textures: the same task that engaged Mr. Pierce more than 100 years ago.

When I come across maps such as the 1890 Nationalities Map it reminds me that, despite the millions of maps generated by sophisticated software every day, few are information rich, complex, and multivariate – Tuftian. At least in this context – the high art and science of multivariate, data-intense mapping – we may not be much better off than we were in 1890.

Making maps is rife with rules. But following rules does not necessarily produce a great (or even good) map. It may be the implementation of broader design principles that leads to a successful map.

Principles are an intellectual generalization of a broad field of knowledge: a kind of map, in the broadest sense of the word.

They are useful for guiding map makers and helping map users understand how maps work.

There are numerous sets of cartographic design principles. My previous post on Edward Tufte distilled six map design principles (or commandments as I called them) from Tufte’s first book, The Visual Display of Quantitative Information.

In 1999 the British Cartographic Society’s Design Group proposed “Five Principles of Cartographic Design.” When I first came across this set of principles I thought them interesting – even a bit passionate – a rare state of affairs in the often stoic world of cartography. I added a few maps and my own comments (in italics).

More on these map design principles below: Concept before Compilation, Hierarchy with Harmony, Simplicity from Sacrifice, Maximum Information at Minimum Cost, and Engage the Emotion to Engage the Mind.

Cool maps below include: Geo-Smiley Terror Spree Map, The Continents and Islands of Mankind, Hate Groups and Hate Crimes Map, and Where Commuters Run Over Black Children, Detroit 1968.

Five Principles of Map Design

Concept before Compilation
Without a grasp of concept, the whole of the design process is negated. The parts embarrass the whole. Once concept is understood, no design or content feature will be included which does not fit it. Design the whole before the part. Design comes in two stages, concept and parameters, and detail in execution. Design once, devise, design again. User first, user last. What does the user want from this map? What can the user get from this map? Is that what they want? If a map were a building, it shouldn’t fall over.

…or, why are you making your map, who is the audience, and what do they want from the map?

•••••

Hierarchy with Harmony
Important things must look important, and the most important thing should look the most important. “They also serve who only stand and wait.” Lesser things have their place and should serve to complement the important. From the whole to the part, and all the parts, contributing to the whole. Associated items must have associated treatment. Harmony is to do with the whole map being happy with itself. Successful harmony leads to repose. Perfect harmony of elements leads to a neutral bloom. Harmony is subliminal.

…or, what’s important? Make it visually jump out. What’s less important, but necessary in a supporting role? Make it fall back…

(Geo-Smiley Terror Spree Map. Reproduced from Making Maps, p. 144)

•••••

Simplicity from Sacrifice
Great design tends towards simplicity (Bertin). Its not what you put in that makes a great map but what you take out. The map design stage is complete when you can take nothing else out. Running the film of an explosion backwards, all possibilities rush to one point. They become the right point. This is the designer’s skill. Content may determine scale or scale may determine content, and each determines the level of generalization (sacrifice).

…or, less is more…

(Redrawn from William Bunge, The Continents and Islands of Mankind. Areas in black have more than 30 people per square mile. Reproduced from Making Maps, p. 160-161)

•••••

Maximum Information at Minimum Cost (after Ziff)
How much information can be gained from this map, at a glance. Functionality not utility. Design makes utility functional. All designs are a compromise, just as a new born baby is a compromise between its father and mother. The spark which makes a map special often only comes when the map is complete.

…or, carefully select the content and marks on the map (symbols) to maximize the map’s information content and communication capabilities…

(Hate Groups and Hate Crimes Map. Apparently more hate groups in a state means fewer hate crimes. Reproduced from Making Maps, p. 208)

•••••

Engage the Emotion to Engage the Understanding
Design with emotion to engage the emotion. Only by feeling what the user feels can we see what the user sees. Good designers use Cartographic fictions, Cartographic impressions, Cartographic illusions to make a map. All of these have emotive contents. The image is the message. Good design is a result of the tension between the environment (the facts) and the designer. Only when the reader engages the emotion, the desire, will they be receptive to the map’s message. Design uses aesthetics but the principles of aesthetics are not those of design. We are not just prettying maps up. The philosophy is simple, beauty (aesthetics) focuses the attention. Focusing the attention is the purpose of map design!

…or, embed a bit of passion…

(Where Commuters Run Over Black Children, Detroit 1968. Detroit Geographical Expedition. The title says it all.)