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thumb_image_imhof_bookcover Swiss Cartographer Eduard Imhof’s classic Cartographic Relief Representation was first published in Deutsche in 1965. It was translated to English 25 years ago, but has remained difficult to find since going out of print. Teaching at the Swiss Institute of Technology in Zurich, his teachings and the contents of the book remain useful to present day cartography students and anyone interested in representing terrains truly. This book breathes passion and knowledge in depth of coverage and is filled with insight every bit as relevant today as it was when first written.




Cartographic Relief Representation

Eduard Imhof

ESRI Press

420 pages; 2007 – ISBN: 978-1-58948-026-1

59.95 USD / 40.50 Euro

Review by Jeff Thurston

There are very few books that cause me to read in awe, ponder quietly in appreciation and realize just how significant others hard work, perception of the world and their passionate devotion to their profession can be. This is one of them.

In 1965 Eduard Imhof published a German textbook entitled Kartographische Gelandedarstellung by de Gruyter Publishers in Berlin. At that time cartography was very much about hardcopy mapping and the task at hand involved representing the earth on a piece of paper. This was no easy task at that time, and it remains so today as we struggle to take a 3D world and put it on a 2D piece of paper. Textbooks discussing procedures and methods for achieving this goal were often unavailable – which made this textbook quite valuable at that time.

Today the same situation exists. There are few textbooks available that students can use to develop their cartographic talents and understanding through the use of computer software, and the internet has brought new techniques and technology for displaying landscapes. Yet, it can still be argued that even with these technologies, a need remains, to be able to understand the primary elements of cartography for making useful maps. As Eduard Imhof says in this book, “the representation of relief is the foundation for all the remaining contents of the map.” Without a doubt even the best maps when rendered on poorly represented relief, provide the viewer with an incorrect view and understanding of the locations they seek to describe.

This book is “directed to cartographers rendering terrain properly.” And, “he who mistakes the goal will never find the path,” as the author points out.

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Beginning at the first chapter, historical developments are presented. Many of the earliest terrain representations simply hinted at mountains, included shaded stretches or irregular lines to identify them because methods for reproducing terrains were not understood fully. Explanations are included, describing where and why this was the case. We learn that some maps lasted for centuries, before being superseded in accuracy and replaced, causing one to wonder how travellers and citizens in many places perceived their local regions, at that time. The development of hachures resulted in forbidding looking landscapes centuries ago, requiring great creativity to represent. Shadow hachures were developed, as well as three-dimensional grading in the early 1800’s, and marine relief followed. Imhof discusses contouring, lithography, multi-color printing and other forms of production. Many of these techniques are still in use, providing a connection between past and present forms of representation techniques and approaches.

In the second chapter an overview of methods used for topographic surveying is presented including plane table surveying, tacheometric, leveling and photogrammetric surveys. Accuracy is discussed in terms of both position and height and the relationship of method to contour lines is shown. Examples of contour line widths are presented and the first instances of cartographic generalization arise, later discussed more fully in later chapters.

Readers today will be interested to learn of the appreciation for ‘quality’ of contour lines at that time – often taken for granted today, where users often accept whatever is computed without questioning how these contour lines are generated. Imhof connects the dots – literally – between surveying and relief representation quality.

The mapmaker should be able to evaluate his bases, the source maps; he should , so to speak, size them up. He should know their advantages, their weaknesses, their contents, the nature of their generalization. Imhof explains that cartographer’s should sketch more often because it is different than observing aerial imagery for map making purposes. Through sketching one adds subjective impressions, which today, we might likely refer to as intelligence and examples such as the Murtschenstock (Glarus Alps, Switzerland) are provided. The book includes a discussion on the topics of aerial photogrammetry and the underlying principles of interpretation as well.

At chapter 5 reader’s become more aware of the intricate nature of creating terrains and the chapter is aptly named ‘The Problem and Its Characteristics.’ Imhof discusses spatial variation and the ability to see depth in the relationship of spatial depth to map design. “Topgraphic maps are symbols which speak to us in a secret language,” stated the well-known geographer and teacher Oscar Peschel from 1868.

It is here that I started to appreciate, that at that time, much experimentation was apparent in the creation of maps in general. Yet, today we still cannot escape this reality: modern digital techniques and technologies continue to place us into a continual dance of experimentation in a similar fashion.

But some of the examples, like the images of circular cones and how they were altered and used to show depth are intriguing to think about and observe. In some cases lines radiate from their center, while in others they are parallel, extending in circular fashion. Hypsometric tinting was experimented with from numerous angles and methods, while concepts like direct and indirect relationships are presented and reviewed.

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A discussion about spot heights and soundings explains survey methods for acquiring elevation data, but it also goes on to explain the relationship of text and text size in describing elevation points and how that influences visual perception. Meanwhile, a more in-depth discussion of contour lines ensues and is supported with deeper questions about accuracy, mathematical calculations for determining survey points in terrain representation and the issue of generalization.

Shading is given a significant level of attention and various types of shading are presented, including shadow formation. As one might expect, a review of perspective is addressed and like horizon spacing and distances for contour lines are discussed, as is slope shading. One gains a strong sense that Imhof is deeply concerned about mixing the elements of realism into map drawing and expression. He also considers perceptive cues and color and tonal variations across landscapes and how they are perceived.

In modern GIS today we simply push a few buttons and can create a continuous terrain from a series of discrete elevation points, then calculate aspects and apply shading for the terrain a few seconds later. This book explains the considerations in developing terrains and how shades and aspects relate to perceptions. What a computer might calculate based upon the data available, could, in reality, be quite different than what the eye will see in reality.

By chapter seven readers will begin to appreciate the significance in the relationship between data and accuracy and true representation of a terrain. In fact, while reading this book and looking at the images, it caused me to be mindful of the many artistic books I have read and how artists have approached and painted landscapes, and the considerations in their representations to gain trueness and exactness, through subjectivity.

We are reminded of the influences that generalization and the unique physical geography of many locations present, and that data reduction can truly render reality into a completely different landscape – if pushed too far. Simple principles like less reduction for hilled and mountainous areas as compared to flatlands must be considered. Similarly, shading has a role in illuminating mountains, enhancing 3D effect and allowing the invisible to become lit and seen.

At one point, Imhof says, “We believe, however, that even with these results [referring to the work of Swiss researchers as late as 1979], the problems of the computer-assisted creation of shaded relief maps are not yet satisfactorily solved.” I found myself wondering if he would think this same thought today, or if we have overcome the issues he thought remained? I suspect, though uncertain, he might see improvements in hill shading today, but that the nature of human perception may still not be realized completely in the approaches and resources we have at hand today. The challenges remaining.

The presentation on hachures in chapter 10 is quite interesting. I’d not thought much about shaded hachures before seeing them in this book and Imhof talks about the 5 rules for construction of slope hachures. He even points to the work of Lehmann from 1799, who developed a scale of relationships for stroke thickness using hachures in relationship to spacing. The graphics in this book are all in black and white (though 14 color plates are present at the rear of the book), and this helps to explain the text in many cases, supporting concepts well. Even examples of misrepresenting slopes are provided side-by-side with the workable solutions, thereby providing the reader with an example of the results of misusing hachures.

You will learn that it is a violation of historical accuracy to reproduce woodcut maps and copper engraved maps to any color other than black and white. The reason being that this impacts depth, shade and graphic sensitivity. Clearly then we are left with the idea that each piece of work is designed, created and represented for a purpose and that its fidelity, use and value is only realized when we maintain these elements. This is an important point, since, today we have photo-copiers that can reproduce almost any representation to any other style or colour, and that with the flick of a mouse button, any given map or drawing can be altered from its original, easily. Such was not the intent of cartographic representation centuries ago, or even in modern cartographic production by professionals today.

Chapter 11 delves into the topic of rock drawing and the author imparts his understanding of geology and how that relates to the creation and representations of terrains. Geologic structure and weathering processes follow specific rules and definitions and these must be followed if certain landscapes are to be represented properly. “The following are also characteristic of the relief structure of high cliffs and rocky masses in alpine regions” steep, rocky erosion gullies are usually very elongated. They are normally scoured out and seldom have stepped profiles.”

It is not wholly surprising that Imhof, a native of Switzerland should devote such a remarkable amount of attention to rocks, mountains and their proper representation. This is part of what makes this book so special. Have you read any other book discussing rock physical geography representation lately?

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Symbolization holds a special place in the minds of most cartographers. A map without it often less useful, and a cartographic representation with good symbology is the difference between a legible piece of paper and a work that explains more than the eye can see.

This book discusses small-feature symbols and artificial slopes, small landform symbols and the topic of dimensions for symbols according to scales. Examples from Switzerland, Germany and France are presented. The subject of color areas is presented and the topic heights of hypsometric steps on land. These are common functions in most GIS handing terrain data today, but not often explained to those creating equidistant, interval and irregular height steps. A similar discussion on the topic of bathymetric steps is also included.

In chapter 14 the topics begin to swing back around to encompass the entire book. The author discusses what is referred to as “The nature and effect of interplay” noting the relationships of conceptual interplay, graphic interplay and technical interplay. Generalization and standardization are once again mentioned, but by now most readers will appreciate these as needs to embrace a more disciplined approach to achieve true representations of terrains. It is interesting at this point to read the words used. For example, the “mutual relationship of things” [included with descriptive pictures of text – symbol overlap]. No technical mumbo-jumbo, like we hear today in the name of branding. And this is why Imhof’s writing seems to work so well; it is straight forward, easy-to-comprehend and uses everyday terms to help us get the message.

Chapter 16 is about the future. Imhof noted the role photogrammetry was playing in speeding up the development of topographic maps. Today we see evidence of this continuing through the use of automation technologies, yet, looking at events like Hurricane Katrina, recent floods in the UK and Germany and the recent Tsunami happening; we can appreciate that a lack of excellent topographic mapping still stands today.

The author speaks about photomaps and the role photogrammetry could play in topographic mapping. Indeed, some of researchers in Germany did in fact pursue this and began successful company’s creating high quality topographic products through photogrammetric techniques – and they still do today. Yet, other researchers began working on triangulated irregular networks (TIN) for the creation of continuous surfaces, after this book was originally printed in 1965, so you will not find this mentioned at any length.

Good maps are not always more expensive than bad maps.”

Such statements are bold, clear and accurate. They remain true today and have as much significance as when first written. Quality matters. Good maps are not expensive as Imhof noted, largely because they can be reused and re-purposed. He mentions that the key to progress in cartography lies in geographic education and training of mapmakers. And today, we could argue that also remains so, perhaps even moreso, as we struggle to understand new 3D technologies and 4D presentations.

This book remains every bit as relevant today as it did when first written in 1965 by Eduard Imhof. Although the author passed away in 1986, the principle of good terrains hold a special place in the study of cartography and representation of maps. They are the foundation for all that is to follow. I find this book to also have particular relevance to how we are approaching cartography and geographic information science today. Are we seduced by the flash of spinning globes and the quickness that data can be merged together from any source today, without caring of its source or its contribution to overall usefulness in the final products we create? We talk about quality, but how do we mean it?

Cartographic Relief Representation is like a gift being delivered. Its wealth of information including basic cartographic techniques, concepts, principles and examples all feel like precious pieces of wisdom and small extraordinary gems of knowledge that can be tucked away for later appreciation and use.

ESRI Press has done well to support this work. In fact, it is a positive reflection on the company that they recognize the value of this book coming to the larger English speaking community and the principles it holds.

This book is a keeper. If you are in any way remotely connected to landscape work, then this book is essential reading. Today we are surrounded by many technologies that distribute maps and geographic content at lightning speed, much of whose content many do not question. In books like this you find the secret codes for unlocking the technological issues facing modern day cartography and geographic data expression. This is because the quality of thought in studying them back then, by people like Eduard Imhof, remains useful and significant through time.

Cartographic Relief Representation is Eduard Imhof’s legacy that has survived time, awaiting the cartographic minds of tomorrow to find, and to begin unlocking the faithful representation of our world in whole new ways, building on new technologies and with new approaches – with renewed passion.

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