GEOG 60 – Introduction to Geographic Information Systems Professor: Dr. Jean-Paul Rodrigue Topic 6 – Cartographic Composition A – Cartography B – Elements of Map Composition C – Cartographic Elements D – Symbolization
Conditions of Usage ■For personal and classroom use only Excludes any other forms of communication such as conference presentations, published reports and papers. ■No modification and redistribution permitted Cannot be published, in whole or in part, in any form (printed or electronic) and on any media without consent. ■Citation Dr. Jean-Paul Rodrigue, Dept. of Economics & Geography, Hofstra University.
The Purpose of this Course ■Understand how elements composing a map should be arranged. ■Know what elements should be placed on a map. ■Use the appropriate symbolism to represent features correctly.
Cartography ■1. Maps and their Uses ■2. Efficiency and Mapping ■3. Cartography and GIS A A
Maps and their Use ■Mapping is a communication tool Convey a message to a public through a medium. Some forms of communication are better than others. All maps are not equal, even if some are representing the same features. Cartographic quality. Maps are using visual communication tools. 1 1 Map InformationMessage CartographyMap reading
Maps and their Use ■Recording and Storing Information Enterprises and institutions are using maps to store large amounts of information. Location of resources. Location of people. Parcels. Property. Infrastructure. Utilities. Etc… 1 1
Maps and their Use ■Analyzing Distributions and Patterns Maps can be used to analyze spatial distributions. Visualization helps conceptualization of patterns and processes. 1 1
Maps and their Use ■Presenting and Communicating Express concepts and ideas that are verbally difficult and complex to portray. Demonstrate. Convince. Persuade. Inform/Misinform. 1 1
Efficiency and Mapping ■Cartography Science / art / technique of map production. Uses a set of defined graphical elements to communicate a message. ■Graphical elements specific to cartography Coordinate systems. Map projections. Scale. Symbolism. ■Legend Explaining the meaning of graphical symbols. With the large diffusion of maps, some symbols do not require explanation anymore. 2 2
Efficiency and Mapping ■Symbolic abstraction Encoding real-world geographic features. How much to simplify? How to symbolize? 2 2
Efficiency and Mapping ■Designing a Good Map A good map conveys well its intended message. ■What is the goal of the map? What the reader should gain from the map or how the reader should respond. Motives vary greatly. Convey accurate information about spatial relationships. Sway public debate. The motive will have a great bearing on the content of the map (the information included) and its form (the cartographic strategies employed). 2 2
Efficiency and Mapping ■Who is the reader? Map design is not the same according to the intended public. Identify the type of reader being addressed. Important to have an idea about what the audience is likely to know about the subject matter of the map. Map literacy: How much background the readers have in using maps. A map intended for specialists who have a background in cartography might be organized far differently than one intended for use in a public debate. 2 2
Efficiency and Mapping ■Where it will be used? Usage depend on the type of medium the map will be published in (book, magazine, news, web site, etc.). Some maps are used only once and then discarded. Others are intended to used for reference for decades or centuries. ■What data is available? Some maps use reliable sources while others have sketchy information. Decisions about map design are tempered greatly by source materials themselves. ■What resources and equipment are available? Underline the time and the costs for map production. 2 2
Cartography and GIS ■Explosion in the generation of maps over the last decades More information is available from several sources. Information is more accurate and in numerical format. GIS enable to produce maps at a very low cost. The population have more map-reading skills. The Internet: Massive distribution of graphical images such as maps. Access to a wide array of public databases. 3 3
Cartography and GIS ■Automated Cartography Computing mapping is a revolution that could be compared to the word-processor for writing. GIS automate several aspects of the cartographic process. Assist cartographers for tasks that previously took a lot of training, time and manual expertise. Map revision is enhanced as errors do not involve starting over again. Can adjust the layout, the composition and symbolization. One map can be duplicated “ad infiniti” to form new maps with the same base map. “GIS don’t make good or bad maps, cartographers do”. 3 3
Cartography and GIS ■Future of cartography Virtual maps: A truly “digitized world”. Official base maps and datasets available for everyone to use. 3-D maps. Animated maps. 3 3
Elements of Map Composition ■1. Format of Final Production ■2. Generalization, Simplification and Abstraction ■3. Common Elements ■4. Balancing Elements ■5. Map Layouts B B
Format and Final Production ■Final format Size and the media will determine the map-making process. Size influence the level of detail and the quantity of information. Media determines the availability of colors, patterns and lettering. 1 1 B&W Insert in an article 3” 5” Poster 24”
Generalization, Simplification and Abstraction ■Cartography is a process of abstraction Features are generalized and simplified. Not all elements are relevant to the message a map convey. The reader must have his/her attention of the message portrayed by the map. ■Detail Too much details undermine the message of the map. The amount of detail is related to the scale of the map. A small scale map must be generalized. A large scale map can contain more details at the expense of generalization. 2 2
Generalization, Simplification and Abstraction 2 2
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Common Elements ■Basic set of elements Title. Scale. Legend. Body of map. North arrow. Production Date. Projection Used. Sources. Most elements are found on all maps, but some are more context sensitive. 3 3
Map Elements The United States of America Alaska Lambert Conformal Conic Projection Source: U.S. Dept. of State hundreds of kilometers Washington,D.C. National Capital Legend Scale CreditsPlace nameInset Background Neat line Title Hawaii 3 3
Balancing Elements ■Concept Each map element has its own importance. The cartographer must organize them according to priority. Important elements should be in prominent positions within the map. Important elements should have an according size; a larger area. ■A general rule: The most important elements should be on the top left. The least important elements should be on the bottom right. 4 4
Balancing the Importance of Elements 4 4 Most important information Least important information Visual Center
Balancing Elements ■Placement Importance should also be given to the placement of elements within the map frame. Distribute evenly to avoid crowding and blank areas. 4 4
Map Layout ■Rules Only experimentation tells which layout is the best. It used to be a costly and long experience. Today, GIS packages enable to do this easily. 5 5
Map Layout ■Relevance of the elements on the map Each one should be justified. Those of less importance should be simplified. Those of importance should be explained. Simple design are more readable. Too much detail and complexity will confuse the reader. The rules are generally vague, so it is to the cartographer to develop his/her “style”. 5 5
Cartographic Elements ■1. Distance and Scale ■2. Direction ■3. Legend ■4. Sources ■5. Context Sensitive Elements ■6. Effective Communication Elements C C
Distance and Scale ■Distance or scale Must always be indicated or implied. Except in the case where the audience is very familiar with the map and the distance portrayed. Verbal, numeric and graphic scale. Graphic form is often preferred: Map are drafted at a different scale than they are printed. If verbal and numeric scales are used, the cartographer must make sure that the map is printed at the precise scale indicated inch equals 10 miles 1:50,000 Verbal Numeric Graphic
Direction ■Conventional North The top of the map is the True North, that is the direction of the North Pole. If the top of the map is not the true north, an arrow indicating the direction of the true north should be placed on the map. ■Magnetic North Changing according to the geophysical conditions of the earth’s crust and core. Navigation maps both contain the magnetic north and the true north. Compass readings show the magnetic north and adjustments are made to find the true north. 2 2 Adjustment to be made (declination)
Direction - Some Examples Where is north on this map? Where is north on this map? 2 2
Legend ■Nature and placement List of symbols used on the map and their significance. Symbols on the map should look exactly the same on the legend. The choice of symbols is open, but they should portray a good abstraction. Some conventions are difficult to escape from. Often, legends are not necessary if textual annotations are put directly on the map. Legend should be placed on an empty part of a map to create some balance. 3 3
Legend 3 3
Sources ■Sources Since a map is an information medium, it must be referenced. Source for the base map. Source for the information portrayed on the map (mostly for thematic maps). Possibility to verify information and the way it was interpreted. Age, accuracy and reliability of data is important. Also relevant to indicate how the data was processed, grouped, generalized and categorized. Only consider cities of more than 20,000. Classes are equidistant. 4 4
Context Sensitive Elements ■Title One of the most essential feature. Its design should be related to the audience. Captions usually take the place of titles in maps for books and journals. Should be comprehensive: Avoid things such as “Map of…”. Avoid long descriptions. “A map of the population growth in Canada between 1980 and 1990 displayed by province” with “Canada population growth by province, ”. “Colonies controlled or ruled by Spain on the eve of the Spanish- American War” with “The Spanish empire in 1898” 5 5
Context Sensitive Elements ■Projection Influences the representation of area, distance and direction. An experienced cartographer can identify the projection simply by looking at the map. Choose the appropriate projection for the mapping context. Some projections are incompatible with some representations. The projection used should be indicated on the map if precision is important. For several thematic maps, projection is factual. Projection is mandatory for maps to be used in the digitizing process. Projection is indicated on all topographic maps. 5 5
Context Sensitive Elements ■Cartographer Name (initials) of the person(s) responsible for the map production. Could also be a corporate identity. Seal of approval since the cartographer is linked to his(her) output. ■Production date Several map are time sensitive. The reader must thus know when the map was produced to understand its context. Illustrates how old is the information, and thus its accuracy. For some maps, the year is all what is needed. For maps, such as weather maps, the time precision can go up to the minute. 5 5
Effective Communication Elements ■Neatlines Used to frame a map and to clearly indicate where it begins and ends. Also used to clip some area out of a locator, inset or index map. Some maps do not need neatlines, notably when they are well- known maps. 6 6 Northeastern United States
Effective Communication Elements ■Locator Some maps show a location unfamiliar to the reader. It is useful to put a locator map portraying where is location in relation to a wider area. ■Inset Information on a specific part of a map may be too dense. Useful in this context to put an inset map to zoom in. ■Index map Limit to the amount of information that can be put on a map. Useful to place labels and other information on an index map. 6 6
Effective Communication Elements - Locator, Inset and Index Maps 6 6
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Symbolization ■1. Visual Resources ■2. Symbolization Strategies ■3. Typography ■4. Foreground and Background ■5. Category Ranges D D
Visual Resources ■Visual resources Used to draw attention on map features. Wide range of resources. Varies according to the nature of the information being mapped. ■Modification of visual elements Can be modified by color and geometry. ■Color modifications Hue. Texture. Intensity. ■Geometric modifications Shape. Size. Orientation. 1 1 HueTextureIntensity ShapeSizeOrientation COLOR GEOMETRY
Visual Resources ■Visual resources and geographical features Different geographical attributes can be represented. N 10 km Location Direction Distance Movement Function Process Correlation 1 1
Visual Resources Cartographer's Conception Point representation Line representation Area representation Volumetric representation Real World Phenomena Point objects Line objects Area objects Volumetric objects Tree X Airport Chemical spill Open-pit mine Highway Tel. poles Phone line Right of way Animals Animal range StreamWatershed Administrative division Housing density Road density Forest cover Proportional symbol Mountain range Valley 1 1
Symbolization Strategies ■Three levels of measurement Nominal (qualitative) data. Ordinal data. Ratio (quantitative) data. ■Nominal Data Information is grouped in categories on the basis of qualitative considerations. 2 2 Town Airport Road Boundary River Swamp Desert Forrest Points Lines Polygons
Symbolization Strategies ■Ordinal Data Grouped by rank on the basis of some quantitative measure. Large Medium Small Highway Road Street Affected area Risk area Points Lines Polygons 2 2
Symbolization Strategies ■Ratio Data Information that can be arranged along a quantitative scale Each dot represents 500 persons Proportional symbols Flow Contour Population density Points Lines Polygons 2 2
Typography ■Definition Placement and appearance of textual information. Very difficult task. The cartographer must be concerned about the content and the form. The content is the relevance and clarity of text. Avoid confusion and misinterpretations. Avoid redundancies. Avoid abbreviations. The form is the appearance of the text on the map. 3 3
Typography ■Font Refers to the shape and pattern of letters. Hundred of fonts are available today, but stick to the basics. Two major categories: Serif and Sans Serif. Sans Serif fonts are easier to read, but readers put more attention on Serif fonts (in theory). Other variances are Bold and Italic. Both used to make text stand out. F o n t s i ze used to play with prominence of the text. As well as UPPER CASE, lower case and Mixed Case. The same information usually has the same font and font size. 3 3
Typography ■Labeling points Avoid lettering across boundaries. Four places relative to a point where you can put text. They are not equally advantageous: 1 (best choice), 2, 3 and then 4 (last choice). Since points do not have an orientation, text should be horizontal. 3 3
Typography ■Lettering Lines and Areas Text should follow the orientation (direction) of the line. It links the text more clearly to the graphic element and thus avoid confusion. Text should occupy the area and its orientation. 3 3
Foreground and Background ■Context Brings the most important information in the foreground. Secondary information should be in the background. The combination of the foreground and the background must be readable, and even enhance readability. Requires the usage of color, value or patterning. Creates some 3-D effect and a visual hierarchy. It helps the reader sorting things out. 4 4 Less important (background) Some importance Important Most Important (foreground)
Foreground and Background 4 4
Category Ranges ■Context Information being mapped is in categories. Use a symbolization that express gradients. Elements that can be played with are the gray scale, the pattern (its density), hue and intensity. Too many categories will confuse the reader (3 - 7 categories). 5 5 Gray Scale Pattern Hue Intensity