Cartography

Cartography (/kɑːrˈtɒɡrəfi/; from Greek χάρτης chartēs, "papyrus, sheet of paper, map"; and γράφειν graphein, "write") is the study and practice of making maps. Combining science, aesthetics, and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively.

The fundamental problems of traditional cartography are to:

  • Set the map's agenda and select traits of the object to be mapped. This is the concern of map editing. Traits may be physical, such as roads or land masses, or may be abstract, such as toponyms or political boundaries.
  • Represent the terrain of the mapped object on flat media. This is the concern of map projections.
  • Eliminate characteristics of the mapped object that are not relevant to the map's purpose. This is the concern of generalization.
  • Reduce the complexity of the characteristics that will be mapped. This is also the concern of generalization.
  • Orchestrate the elements of the map to best convey its message to its audience. This is the concern of map design.

Modern cartography constitutes many theoretical and practical foundations of geographic information systems.

Claudius Ptolemy- The World
A medieval depiction of the Ecumene (1482, Johannes Schnitzer, engraver), constructed after the coordinates in Ptolemy's Geography and using his second map projection. The translation into Latin and dissemination of Geography in Europe, in the beginning of the 15th century, marked the rebirth of scientific cartography, after more than a millennium of stagnation.

History

Paspardo roccia Vite29 rilievo foto
Valcamonica rock art (I), Paspardo r. 29, topographic composition, 4th millennium BCE
Bedolina roccia 1 foto rilievo
The Bedolina Map and its tracing, 6th–4th century BCE
Add 19391 19-20
A 14th-century Byzantine map of the British Isles from a manuscript of Ptolemy's Geography, using Greek numerals for its graticule: 52–63°N of the equator and 6–33°E from Ptolemy's Prime Meridian at the Fortunate Isles.
T and O map Guntherus Ziner 1472
Copy (1472) of St. Isidore's TO map of the world.

Ancient times

What is the earliest known map is a matter of some debate, both because the term "map" is not well-defined and because some artifacts that might be maps might actually be something else. A wall painting that might depict the ancient Anatolian city of Çatalhöyük (previously known as Catal Huyuk or Çatal Hüyük) has been dated to the late 7th millennium BCE.[1][2] Among the prehistoric alpine rock carvings of Mount Bego (France) and Valcamonica (Italy), dated to the 4th millennium BCE, geometric patterns consisting of dotted rectangles and lines are widely interpreted[3][4] in archaeological literature as a depiction of cultivated plots.[5] Other known maps of the ancient world include the Minoan "House of the Admiral" wall painting from c. 1600 BCE, showing a seaside community in an oblique perspective, and an engraved map of the holy Babylonian city of Nippur, from the Kassite period (14th – 12th centuries BCE).[6] The oldest surviving world maps are from 9th century BCE Babylonia.[7] One shows Babylon on the Euphrates, surrounded by Assyria, Urartu[8] and several cities, all, in turn, surrounded by a "bitter river" (Oceanus).[9] Another depicts Babylon as being north of the center of the world.[7]

The ancient Greeks and Romans created maps from the time of Anaximander in the 6th century BCE.[10] In the 2nd century CE, Ptolemy wrote his treatise on cartography, Geographia.[11] This contained Ptolemy's world map – the world then known to Western society (Ecumene). As early as the 8th century, Arab scholars were translating the works of the Greek geographers into Arabic.[12]

In ancient China, geographical literature dates to the 5th century BCE. The oldest extant Chinese maps come from the State of Qin, dated back to the 4th century BCE, during the Warring States period. In the book of the Xin Yi Xiang Fa Yao, published in 1092 by the Chinese scientist Su Song, a star map on the equidistant cylindrical projection.[13][14] Although this method of charting seems to have existed in China even before this publication and scientist, the greatest significance of the star maps by Su Song is that they represent the oldest existent star maps in printed form.

Early forms of cartography of India included depictions of the pole star and surrounding constellations.[15] These charts may have been used for navigation.[15]

Middle Ages to Renaissance

"Mappae mundi ("maps of the world") are the medieval European maps of the world. About 1,100 of these are known to have survived: of these, some 900 are found illustrating manuscripts and the remainder exist as stand-alone documents.[16]

The Arab geographer Muhammad al-Idrisi produced his medieval atlas Tabula Rogeriana (Book of Roger) in 1154. By combining the knowledge of Africa, the Indian Ocean, Europe, and the Far East (which he learned through contemporary accounts from Arab merchants and explorers) with the information he inherited from the classical geographers, he was able to write detailed descriptions of a multitude of countries. Along with the substantial text he had written, he created a world map influenced mostly by the Ptolemaic conception of the world, but with significant influence from multiple Arab geographers. It remained the most accurate world map for the next three centuries.[17][18] The map was divided into seven climatic zones, with detailed descriptions of each zone. As part of this work, a smaller, circular map was made depicting the south on top and Arabia in the center. Al-Idrisi also made an estimate of the circumference of the world, accurate to within 10%.[19]

In the Age of Exploration, from the 15th century to the 17th century, European cartographers both copied earlier maps (some of which had been passed down for centuries) and drew their own, based on explorers' observations and new surveying techniques. The invention of the magnetic compass, telescope and sextant enabled increasing accuracy. In 1492, Martin Behaim, a German cartographer, made the oldest extant globe of the Earth.[20]

In 1507, Martin Waldseemüller produced a globular world map and a large 12-panel world wall map (Universalis Cosmographia) bearing the first use of the name "America". Portuguese cartographer Diego Ribero was the author of the first known planisphere with a graduated Equator (1527). Italian cartographer Battista Agnese produced at least 71 manuscript atlases of sea charts. Johannes Werner refined and promoted the Werner projection. This was an equal-area, heart-shaped world map projection (generally called a cordiform projection) which was used in the 16th and 17th centuries. Over time, other iterations of this map type arose; most notable are the sinusoidal projection and the Bonne projection. The Werner projection places its standard parallel at the North Pole; a sinusoidal projection places its standard parallel at the equator; and the Bonne projection is intermediate between the two.[21][22]

In 1569, mapmaker Gerardus Mercator first published a map based on his Mercator projection, which uses equally-spaced parallel vertical lines of longitude and parallel latitude lines spaced farther apart as they get farther away from the equator. By this construction, courses of constant bearing are conveniently represented as straight lines for navigation. The same property limits its value as a general-purpose world map because regions are shown as increasingly larger than they actually are the further from the equator they are. Mercator is also credited as the first to use the word "atlas" to describe a collection of maps. In the later years of his life, Mercator resolved to create his Atlas, a book filled with many maps of different regions of the world, as well as a chronological history of the world from the Earth's creation by God until 1568. He was unable to complete it to his satisfaction before he died. Still, some additions were made to the Atlas after his death and new editions were published after his death.[23][24]

In the renaissance, maps were used to impress viewers and establish the owner's reputation as sophisticated, educated, and worldly. Because of this,  towards the end of the renaissance, maps were displayed with equal importance of painting, sculptures, and other pieces of art.[25] In the sixteenth century, maps were becoming increasingly available to consumers through the introduction of print making, with about 10% of Venetian homes having some sort of map by the late 1500s.

There were three main functions of maps in the Renaissance:[26]

·      General descriptions of the world

·      Navigation (both land and sea)

·      Land surveys/property management

In medieval times, written directions of how to get somewhere were more common than the use of maps. Coming with the renaissance, cartography was seen as a metaphor for power.[26] Political leaders could lay claim on territories through the use of maps and this was greatly aided by the religious and colonial expansion of Europe. The most commonly mapped place was the Holy Land and other religious places in the renaissance.

In the late 1400s to the late 1500s Rome, Florence, and Venice dominated map making and trade. It started in Florence in the mid  to late 1400s. Map trade was quickly shifted to Rome and Venice and then over taken by atlas makers in the late 16th century.[27] Map publishing in Venice was completed with humanities and book publishing in mind, rather than just informational use.

Map Style

There were two main methods of print making of maps in the renaissance:

The first method was relief. Medium grained hard wood was used as the print blocks where the maps were cut into. the wood was engraved so the areas that were printed appeared as a relief in the wood causing indented lines to appear on the paper. The indented lines could often be felt on the back of the map. There were advantages to using relief to make maps. To make the maps, a print makers didn’t need a press, because the maps could be developed as rubbings. The wood block was durable and could be used multiple times before any appeared. Existing printing presses could be used to create the prints rather than having to create a new one. On the other hand, it was difficult to get fine details with the relief technique. Inconsistent lines and other detail could be more easily observed than inconsistencies in intaglio. To combat this issue, in the late fifteenth century a style of relief came about that used fine chisels to relieve the wood, rather then the typically used knife

The second method was intaglio where lines were engraved into workable metals such as copper or brass. The engraver would spread a thin sheet of wax over the metal plate and then use ink to draw the details of the map. Then, the engraver would trace the main lines with metal tools onto the plate beneath.[28] The engraver could also use metal tools to lightly prick holes along the drawn lines and then tracing it with colored chalk and then engrave the map.  Lines that were going in the same direction were carved at the same time, and then the plate was turned to carve lines going in another direction. Once ink was applied over the metal, the plate made a mark of ink around the border of the map which became known as the "plate-mark". Often times the plate-mark was removed from the edge of the map before it was distributed.[29] Copper and other metals were expensive at the time, so the plate was often reused or melted down for other purposes.[29]

Both relief and intaglio were used about equally by the end of the fifteenth century. Any type of paper that was available at the time could be used to print the map on, but thicker paper was more durable. After the maps were run through the press, the paper was often hung out to dry. Once the map was completely dry, it was usually placed in another press of flatten the paper.

Lettering in map making is important to denote information that is expressed by the map. When using wood, creating fine and small lettering was difficult. Lettering often was often square and blocky, which was a far cry from the stylized, rounded writing style that made itself popular in Italy at the time.[29] To combat this, mapmakers used topography for small lettering. In intaglio lettering was a less difficult than that of wood engraving and was stylized in looping cursive that came to be known as cancellaresca.[29] There were custom-made reverse punches that were also used in metal engraving along side freehand lettering. Identical and mass-produced maps were not appealing to the public, however some map makers adopted identical map keys such as tents, animals, ships, and towns.[28]

The first use of color in map making cannot be narrowed down to one reason. There are arguments that color was first use to indicate information on the map with aesthetics coming second in thought. There are also arguments that color was first used on maps for aesthetics and then evolved into conveying information on the map[29]. Despite these arguments, Italian maps of the Renaissance were often uncolored. It is theorized that these maps were not colored to maintain the delicate details that were made in the map. In the seventeenth century a practice of washing or limning was done to maps. Limning was originally the adding of silver and gold to the map to illuminate of lettering or heraldic arms. Washing originally meant applying watercolor washes to completed maps. Towards the end of the century, washing meant painting the map with watercolor.

Modern times

Due to the sheer physical difficulties inherent in cartography, map-makers frequently lifted material from earlier works without giving credit to the original cartographer. For example, one of the most famous early maps of North America is unofficially known as the "Beaver Map", published in 1715 by Herman Moll. This map is an exact reproduction of a 1698 work by Nicolas de Fer. De Fer in turn had copied images that were first printed in books by Louis Hennepin, published in 1697, and François Du Creux, in 1664. By the 18th century, map-makers started to give credit to the original engraver by printing the phrase "After [the original cartographer]" on the work.[30]

Technological changes

Fernão Vaz Dourado 1571-1
A pre-Mercator nautical chart of 1571, from Portuguese cartographer Fernão Vaz Dourado (c. 1520–c. 1580). It belongs to the so-called plane chart model, where observed latitudes and magnetic directions are plotted directly into the plane, with a constant scale, as if the Earth were a plane (Portuguese National Archives of Torre do Tombo, Lisbon).
Structureforet
Mapping can be done with GPS and laser rangefinder directly in the field. Image shows mapping of forest structure (position of trees, dead wood and canopy).

In cartography, technology has continually changed in order to meet the demands of new generations of mapmakers and map users. The first maps were produced manually, with brushes and parchment; so they varied in quality and were limited in distribution. The advent of magnetic devices, such as the compass and much later, magnetic storage devices, allowed for the creation of far more accurate maps and the ability to store and manipulate them digitally.

Advances in mechanical devices such as the printing press, quadrant and vernier, allowed the mass production of maps and the creation of accurate reproductions from more accurate data. Hartmann Schedel was one of the first cartographers to use the printing press to make maps more widely available. Optical technology, such as the telescope, sextant and other devices that use telescopes, allowed accurate land surveys and allowed mapmakers and navigators to find their latitude by measuring angles to the North Star at night or the Sun at noon.

Advances in photochemical technology, such as the lithographic and photochemical processes, make possible maps with fine details, which do not distort in shape and which resist moisture and wear. This also eliminated the need for engraving, which further speeded up map production.

In the 20th century, aerial photography, satellite imagery, and remote sensing provided efficient, precise methods for mapping physical features, such as coastlines, roads, buildings, watersheds, and topography. The United States Geological Survey has devised multiple new map projections, notably the Space Oblique Mercator for interpreting satellite ground tracks for mapping the surface. The use of satellites and space telescopes now allows researchers to map other planets and moons in outer space.[31] Advances in electronic technology ushered in another revolution in cartography: ready availability of computers and peripherals such as monitors, plotters, printers, scanners (remote and document) and analytic stereo plotters, along with computer programs for visualization, image processing, spatial analysis, and database management, democratized and greatly expanded the making of maps. The ability to superimpose spatially located variables onto existing maps created new uses for maps and new industries to explore and exploit these potentials. See also digital raster graphic.

These days most commercial-quality maps are made using software of three main types: CAD, GIS and specialized illustration software. Spatial information can be stored in a database, from which it can be extracted on demand. These tools lead to increasingly dynamic, interactive maps that can be manipulated digitally.

Field-rugged computers, GPS, and laser rangefinders make it possible to create maps directly from measurements made on site.

Deconstruction

There are technical and cultural aspects to producing maps. In this sense, maps can sometimes be said to be biased. The study of bias, influence, and agenda in making a map is what comprise a map's deconstruction. A central tenet of deconstructionism is that maps have power. Other assertions are that maps are inherently biased and that we search for metaphor and rhetoric in maps.[32]

It is claimed that the Europeans promoted an "epistemological" understanding of the map as early as the 17th century.[32] An example of this understanding is that "[European reproduction of terrain on maps] reality can be expressed in mathematical terms; that systematic observation and measurement offer the only route to cartographic truth…".[32] 17th century map-makers were careful and precise in their strategic approaches to maps based on a scientific model of knowledge. Popular belief at the time was that this scientific approach to cartography was immune to the social atmosphere.

A common belief is that science heads in a direction of progress, and thus leads to more accurate representations of maps. In this belief European maps must be superior to others, which necessarily employed different map-making skills. "There was a 'not cartography' land where lurked an army of inaccurate, heretical, subjective, valuative, and ideologically distorted images. Cartographers developed a 'sense of the other' in relation to nonconforming maps."[32]

Although cartography has been a target of much criticism in recent decades, a cartographer's 'black box' always seemed to be naturally defended to the point where it overcame the criticism. However, to later scholars in the field, it was evident that cultural influences dominate map-making.[32] For instance, certain abstracts on maps and the map-making society itself describe the social influences on the production of maps. This social play on cartographic knowledge "…produces the 'order' of [maps'] features and the 'hierarchies of its practices.'"[33]

Depictions of Africa are a common target of deconstructionism.[34] According to deconstructionist models, cartography was used for strategic purposes associated with imperialism and as instruments and representations of power[35] during the conquest of Africa. The depiction of Africa and the low latitudes in general on the Mercator projection has been interpreted as imperialistic and as symbolic of subjugation due to the diminished proportions of those regions compared to higher latitudes where the European powers were concentrated.[36]

Maps furthered imperialism and colonization of Africa in practical ways by showing basic information like roads, terrain, natural resources, settlements, and communities. Through this, maps made European commerce in Africa possible by showing potential commercial routes, and made natural resource extraction possible by depicting locations of resources. Such maps also enabled military conquests and made them more efficient, and imperial nations further used them to put their conquests on display. These same maps were then used to cement territorial claims, such as at the Berlin Conference of 1884–1885.[35]

Before 1749, maps of the African continent had African kingdoms drawn with assumed or contrived boundaries, with unknown or unexplored areas having drawings of animals, imaginary physical geographic features, and descriptive texts. In 1748, Jean B. B. d'Anville created the first map of the African continent that had blank spaces to represent the unknown territory.[35] This was revolutionary in cartography and the representation of power associated with map making.

Map types

General vs. thematic cartography

Orienteringskort bygholm 2005 detail
Small section of an orienteering map.
Easter Island map-en
Topographic map of Easter Island.
Maps-for-free Sierra Nevada
Relief map Sierra Nevada

In understanding basic maps, the field of cartography can be divided into two general categories: general cartography and thematic cartography. General cartography involves those maps that are constructed for a general audience and thus contain a variety of features. General maps exhibit many reference and location systems and often are produced in a series. For example, the 1:24,000 scale topographic maps of the United States Geological Survey (USGS) are a standard as compared to the 1:50,000 scale Canadian maps. The government of the UK produces the classic 1:50,000 (replacing the older 1 inch to 1 mile) "Ordnance Survey" maps of the entire UK and with a range of correlated larger- and smaller-scale maps of great detail. Many private mapping companies have also produced thematic map series.

Thematic cartography involves maps of specific geographic themes, oriented toward specific audiences. A couple of examples might be a dot map showing corn production in Indiana or a shaded area map of Ohio counties, divided into numerical choropleth classes. As the volume of geographic data has exploded over the last century, thematic cartography has become increasingly useful and necessary to interpret spatial, cultural and social data.

A third type of map is known as an "orienteering," or special purpose map. This type of map falls somewhere between thematic and general maps. They combine general map elements with thematic attributes in order to design a map with a specific audience in mind. Oftentimes, the type of audience an orienteering map is made for is in a particular industry or occupation. An example of this kind of map would be a municipal utility map.[37]

Topographic vs. topological

A topographic map is primarily concerned with the topographic description of a place, including (especially in the 20th and 21st centuries) the use of contour lines showing elevation. Terrain or relief can be shown in a variety of ways (see Cartographic relief depiction). In the present era, one of the most widespread and advanced methods used to form topographic maps is to use computer software to generate digital elevation models which show shaded relief. Before such software existed, cartographers had to draw shaded relief by hand. One cartographer who is respected as a master of hand-drawn shaded relief is the Swiss professor Eduard Imhof whose efforts in hill shading were so influential that his method became used around the world despite it being so labor-intensive.[38][39]

A topological map is a very general type of map, the kind one might sketch on a napkin. It often disregards scale and detail in the interest of clarity of communicating specific route or relational information. Beck's London Underground map is an iconic example. Although the most widely used map of "The Tube," it preserves little of reality: it varies scale constantly and abruptly, it straightens curved tracks, and it contorts directions. The only topography on it is the River Thames, letting the reader know whether a station is north or south of the river. That and the topology of station order and interchanges between train lines are all that is left of the geographic space.[40] Yet those are all a typical passenger wishes to know, so the map fulfills its purpose.[41]

Map design

Livingston-Greenwich-map
Illustrated map.

Map purpose and selection of information

Arthur H. Robinson, an American cartographer influential in thematic cartography, stated that a map not properly designed "will be a cartographic failure." He also claimed, when considering all aspects of cartography, that "map design is perhaps the most complex."[42] Robinson codified the mapmaker's understanding that a map must be designed foremost with consideration to the audience and its needs.

Cartography of Washington State, Mount Rainier National Park, Pinnacle Peak trail
3D cartography of Washington State, Mount Rainier National Park, Pinnacle Peak trail.

From the very beginning of mapmaking, maps "have been made for some particular purpose or set of purposes".[43] The intent of the map should be illustrated in a manner in which the percipient acknowledges its purpose in a timely fashion. The term percipient refers to the person receiving information and was coined by Robinson.[44] The principle of figure-ground refers to this notion of engaging the user by presenting a clear presentation, leaving no confusion concerning the purpose of the map. This will enhance the user's experience and keep their attention. If the user is unable to identify what is being demonstrated in a reasonable fashion, the map may be regarded as useless.

Making a meaningful map is the ultimate goal. Alan MacEachren explains that a well designed map "is convincing because it implies authenticity".[45] An interesting map will no doubt engage a reader. Information richness or a map that is multivariate shows relationships within the map. Showing several variables allows comparison, which adds to the meaningfulness of the map. This also generates hypothesis and stimulates ideas and perhaps further research. In order to convey the message of the map, the creator must design it in a manner which will aid the reader in the overall understanding of its purpose. The title of a map may provide the "needed link" necessary for communicating that message, but the overall design of the map fosters the manner in which the reader interprets it.[46]

In the 21st century it is possible to find a map of virtually anything from the inner workings of the human body to the virtual worlds of cyberspace. Therefore, there are now a huge variety of different styles and types of map – for example, one area which has evolved a specific and recognisable variation are those used by public transport organisations to guide passengers, namely urban rail and metro maps, many of which are loosely based on 45 degree angles as originally perfected by Harry Beck and George Dow.

Naming conventions

Most maps use text to label places and for such things as the map title, legend and other information. Although maps are often made in one specific language, place names often differ between languages. So a map made in English may use the name Germany for that country, while a German map would use Deutschland and a French map Allemagne. A non-native term for a place is referred to as an exonym.

In some cases the correct name is not clear. For example, the nation of Burma officially changed its name to Myanmar, but many nations do not recognize the ruling junta and continue to use Burma. Sometimes an official name change is resisted in other languages and the older name may remain in common use. Examples include the use of Saigon for Ho Chi Minh City, Bangkok for Krung Thep and Ivory Coast for Côte d'Ivoire.

Difficulties arise when transliteration or transcription between writing systems is required. Some well-known places have well-established names in other languages and writing systems, such as Russia or Rußland for Росси́я, but in other cases a system of transliteration or transcription is required. Even in the former case, the exclusive use of an exonym may be unhelpful for the map user. It will not be much use for an English user of a map of Italy to show Livorno only as "Leghorn" when road signs and railway timetables show it as "Livorno". In transliteration, the characters in one script are represented by characters in another. For example, the Cyrillic letter Р is usually written as R in the Latin script, although in many cases it is not as simple as a one-for-one equivalence. Systems exist for transliteration of Arabic, but the results may vary. For example, the Yemeni city of Mocha is written variously in English as Mocha, Al Mukha, al-Mukhā, Mocca and Moka. Transliteration systems are based on relating written symbols to one another, while transcription is the attempt to spell in one language the phonetic sounds of another. Chinese writing is now usually converted to the Latin alphabet through the Pinyin phonetic transcription systems. Other systems were used in the past, such as Wade-Giles, resulting in the city being spelled Beijing on newer English maps and Peking on older ones.

Further difficulties arise when countries, especially former colonies, do not have a strong national geographic naming standard. In such cases, cartographers may have to choose between various phonetic spellings of local names versus older imposed, sometimes resented, colonial names. Some countries have multiple official languages, resulting in multiple official placenames. For example, the capital of Belgium is both Brussel and Bruxelles. In Canada, English and French are official languages and places have names in both languages. British Columbia is also officially named la Colombie-Britannique. English maps rarely show the French names outside of Quebec, which itself is spelled Québec in French.[47]

The study of placenames is called toponymy, while that of the origin and historical usage of placenames as words is etymology.

In order to improve legibility or to aid the illiterate, some maps have been produced using pictograms to represent places. The iconic example of this practice is Lance Wyman's early plans for the Mexico City Metro, on which stations were shown simply as stylized logos. Wyman also prototyped such a map for the Washington Metro, though ultimately the idea was rejected. Other cities experimenting with such maps are Fukuoka, Guadalajara and Monterrey.[40]

Map symbology

Cartographic symbology encodes information on the map in ways intended to convey information to the map reader efficiently, taking into consideration the limited space on the map, models of human understanding through visual means, and the likely cultural background and education of the map reader. Symbology may be implicit, using universal elements of design, or may be more specific to cartography or even to the map.

A map may have any of many kinds of symbolization. Some examples are:

  • A legend, or key, explains the map's pictorial language.
  • A title indicates the region and perhaps the theme that the map portrays.
  • A neatline frames the entire map image.
  • A compass rose or north arrow provides orientation.
  • An overview map gives global context for the primary map.
  • A bar scale translates between map measurements and real distances.
  • A map projection provides a way to represent the curved surface on the plane of the map.

The map may declare its sources, accuracy, publication date and authorship, and so forth. The map image itself portrays the region.

Map coloring is another form of symbology, one whose importance can reach beyond aesthetic. In complex thematic maps, for example, the color scheme's structure can critically affect the reader's ability to understand the map's information. Modern computer displays and print technologies can reproduce much of the gamut that humans can perceive, allowing for intricate exploitation of human visual discrimination in order to convey detailed information.

Quantitative symbols give a visual indication of the magnitude of the phenomenon that the symbol represents. Two major classes of symbols are used to portray quantity. Proportional symbols change size according to phenomenon's magnitude, making them appropriate for representing statistics. Choropleth maps portray data collection areas, such as counties or census tracts, with color. Using color this way, the darkness and intensity (or value) of the color is evaluated by the eye as a measure of intensity or concentration.

Map key or legend

Legenda Michelin kaart 1940
Legend or key of a Belgian road map (Michelin 1940)

The map key, or legend, describes how to interpret the map's symbols and may give details of publication and authorship.

Symbol Explanation
Schlaegel und Eisen nach DIN 21800.svg Schlaegel und Eisen nach DIN 21800 gedreht um 180 Grad.svg mine (Hammer and pick symbol), former mine
Gfi-set01-castle.png Gfi-set01-castle1.png castle, Burg
Set01-church.svg Set01-church1.svg church, chapel, monastery ()
Gfi-set01-memorial.png monument
Gfi-set01-hostel.svg Hotel
Gfi-set01-airport.png Gfi-set01-airport1.png airport
Gfi-set01-railway.png Gfi-set01-railway1.png railway station
Gfi-set01-info.png Info Simple.svg Tourist information

Map labeling

Most maps label features so that the map reader can know features' names. For example, country names may be printed on a world map, each label within the outline of the country it names. Features and background may be in any color, which can make reading labels printed over them harder to read than reading text from a book.[48] Two traits of good labels are legibility and easy feature association. In order for a label to be legible, it must have a type, size and color that are easy to read. Ideally, a label would not interfere with other map features or labels. A halo may be placed around the label to contrast it against the background. A label must also be easily associated with the feature it names, regardless of the feature's category or extent. Choosing a location for a label to enhance this association while avoiding clutter and conflict with other labels is an art that incorporates many techniques. One technique is to use a different font per category of feature. For example, using an italicized, dark blue font for a water label can suggest waves. Or, labels for contour lines can be thin and have the same color as the contours. In difficult cases where there is not enough space to place the label near the feature to form an unambiguous association, a leader line can connect the label to the feature.

Map generalization

A good map has to compromise between portraying the items of interest (or themes) in the right place on the map, and the need to show that item using text or a symbol, which take up space on the map and might displace some other item of information. The cartographer is thus constantly making judgements about what to include, what to leave out and what to show in a slightly incorrect place. This issue assumes more importance as the scale of the map gets smaller (i.e. the map shows a larger area) because the information shown on the map takes up more space on the ground. A good example from the late 1980s was the Ordnance Survey's first digital maps, where the absolute positions of major roads were sometimes a scale distance of hundreds of meters away from ground truth, when shown on digital maps at scales of 1:250,000 and 1:625,000, because of the overriding need to annotate the features.

Map projections

The Earth being spherical, any flat representation generates distortions such that shapes and areas cannot both be conserved simultaneously, and distances can never all be preserved.[49] The mapmaker must choose a suitable map projection according to the space to be mapped and the purpose of the map.

Cartographic errors

Some maps contain deliberate errors or distortions, either as propaganda or as a "watermark" to help the copyright owner identify infringement if the error appears in competitors' maps. The latter often come in the form of nonexistent, misnamed, or misspelled "trap streets".[50] Other names and forms for this are paper townsites, fictitious entries, and copyright easter eggs.[51]

Another motive for deliberate errors is cartographic "vandalism": a mapmaker wishing to leave his or her mark on the work. Mount Richard, for example, was a fictitious peak on the Rocky Mountains' continental divide that appeared on a Boulder County, Colorado map in the early 1970s. It is believed to be the work of draftsman Richard Ciacci. The fiction was not discovered until two years later.

Sandy Island (New Caledonia) is an example of a fictitious location that stubbornly survives, reappearing on new maps copied from older maps while being deleted from other new editions.

See also

References

  1. ^ Robert Kunzig (May 1999). "A Tale of two obsessed archeologists, one ancient city, and nagging doubts about whether science can ever hope to reveal the past". Discover Magazine.
  2. ^ Stephanie Meece (2006). "A bird's eye view – of a leopard's spots. The Çatalhöyük 'map' and the development of cartographic representation in prehistory". Anatolian Studies. 56: 1–16. JSTOR 20065543.
  3. ^ Bicknell, Clarence (1913). A Guide to the prehistoric Engravings in the Italian Maritime Alps, Bordighera.
  4. ^ Delano Smith, Catherine (1987). Cartography in the Prehistoric Period in the Old World: Europe, the Middle East, and North Africa. In: Harley J.B., Woodward D. (eds.), The History of Cartography: Cartography in Prehistoric, Ancient and Mediaeval Europe and the Mediterranean v. 1, Chicago: 54-101 online, retrieved December 2, 2014.
  5. ^ Arcà, Andrea (2004). The topographic engravings of the Alpine rock-art: fields, settlements and agricultural landscapes. In Chippindale C., Nash G. (eds.) The figured landscapes of Rock-Art, Cambridge University Press, pp. 318-349; online academia.edu, retrieved December 2, 2014.
  6. ^ Uchicago.edu The Nippur Expedition
  7. ^ a b Kurt A. Raaflaub; Richard J. A. Talbert (2009). Geography and Ethnography: Perceptions of the World in Pre-Modern Societies. John Wiley & Sons. p. 147. ISBN 978-1-4051-9146-3.
  8. ^ Catherine Delano Smith (1996). "Imago Mundi's Logo the Babylonian Map of the World". Imago Mundi. 48: 209–211. doi:10.1080/03085699608592846. JSTOR 1151277.
  9. ^ Finel, Irving (1995). "A join to the map of the world: A notable discovery". British Museum Magazine. 23: 26–27.
  10. ^ "History of Cartography". Archived from the original on 2009-10-31.
  11. ^ J. L. Berggren, Alexander Jones; Ptolemy's Geography By Ptolemy, Princeton University Press, 2001 ISBN 0-691-09259-1
  12. ^ Geography. Archived from the original on 2009-10-31.
  13. ^ Miyajima, Kazuhiko (1997). "Projection methods in Chinese, Korean and Japanese star maps". In Johannes Andersen (ed.). Highlights of Astronomy. 11B. Norwell: Kluwer Academic Publishers. p. 714. ISBN 978-0-7923-5556-4.
  14. ^ Needham, Joseph (1971). Part 3: Civil Engineering and Nautics. Science and Civilization in China. 4. Cambridge University Press. p. 569. ISBN 978-0-521-07060-7.
  15. ^ a b Sircar, D. C. C. (1990). Studies in the Geography of Ancient and Medieval India. Motilal Banarsidass Publishers. p. 330. ISBN 978-81-208-0690-0.
  16. ^ Woodward, p. 286
  17. ^ S. P. Scott (1904), History of the Moorish Empire, pp. 461–462.
  18. ^ "Muhammad ibn Muhammad al-Idrisi". Encyclopedia of World Biography. Retrieved 27 Jul 2018.
  19. ^ Parry, James (January 2004). "Mapping Arabia". Saudi Aramco World. 55: 20–37.
  20. ^ Globes and Terrain Models – Geography and Maps: An Illustrated Guide, Library of Congress
  21. ^ Henry Bottomley, « Between the Sinusoidal projection and the Werner: an alternative to the Bonne », Cybergeo : European Journal of Geography [Online], Cartography, Images, GIS, document 241, Online since 13 June 2003, connection on 27 July 2018. URL : http://journals.openedition.org/cybergeo/3977 ; DOI : 10.4000/cybergeo.3977
  22. ^ Snyder, John (2007-09-01). "Map Projections in the Renaissance" (PDF). University of Chicago Press.
  23. ^ Britannica, Encyclopedia (2018-01-25). "Mercator Projection". Encyclopedia Britannica.
  24. ^ Britannica, Encyclopedia (2018-02-26). "Gerardus Mercator". Encyclopedia Britannica.
  25. ^ Carlton, Genevieve (2011). "Worldly Consumer: The Demand for Maps in Renaissance Italy". Imago Mundi. 63: 123–126.
  26. ^ a b Woodward, David. "Cartography and the Renaissance: Continuity and Change". The History of Cartography. 3: 3–24.
  27. ^ Woodward, David. "The Italian Map Trade: 1480-1650". The History of Cartography. 3: 773–790.
  28. ^ a b Delano-Smith, Catherine (2005). "Stamped Signs on Manuscripts Maps in the Renaissance". Imago Mundi. 57: 59–62.
  29. ^ a b c d e Woodward, David. "Techniques of Map Engraving, Printing, and Coloring in the European Renaissance". The History of Cartography. 3: 591–610.
  30. ^ "Map Imitation" in Detecting the Truth: Fakes, Forgeries and Trickery, a virtual museum exhibition at Library and Archives Canada
  31. ^ Snyder, John (1987). "Map projections: A Working Manual". United States Geological Survey.
  32. ^ a b c d e Harley, J. B. (1989). "Deconstructing the Map". Cartographica, Vol. 26, No. 2. pp 1-5
  33. ^ Michel Foucault, The Order of Things: An Archaeology of the Human Sciences. A Translation of Les mots et les choses. New York: Vintage Books, 1973.
  34. ^ Stone, Jeffrey C. (1988). "Imperialism, Colonialism and Cartography". Transactions of the Institute of British Geographers, N.S. 13. Pp 57.
  35. ^ a b c Bassett, J. T. (1994). "Cartography and Empire Building in the Nineteenth-Century West Africa". Geographical Review, Vol. 84, No. 3. Pp 316.
  36. ^ Monmonier, Mark (2004). Rhumb Lines and Map Wars: A Social History of the Mercator Projection p. 152. Chicago: The University of Chicago Press. (Thorough treatment of the social history of the Mercator projection and Gall–Peters projections.)
  37. ^ Dutton, John. "Cartography and Visualization Part I: Types of Maps". Penn State University E-Education.
  38. ^ Kennelly, Patrick (2006). "A Uniform Sky Illumination Model to Enhance Shading of Terrain and Urban Areas". Cartography and Geographic Information Science. 33: 21–36. doi:10.1559/152304006777323118.
  39. ^ Ormeling, F.J. (1986-12-31). "Eduard Imhof (1895–1986)". International Cartographic Association.
  40. ^ a b Ovenden, Mark (2007). Transit Maps of the World. New York, New York: Penguin Books. p. 22, 60, 131, 132, 135. ISBN 978-0-14-311265-5.
  41. ^ Devlin, Keith (2002). The Millennium Problems. New York, New York: Basic Books. pp. 162–163. ISBN 978-0-465-01730-0.
  42. ^ Robinson, A.H. (1953). Elements of Cartography. New York: John Wiley & Sons. ISBN 978-0-471-72805-4.
  43. ^ Robinson, A.H. (1982). Early Thematic Mapping: In the History of Cartography. Chicago: The University of Chicago Press. ISBN 978-0-226-72285-6.
  44. ^ MacEachren, A.M. (1995). How Maps Work. New York: The Guilford Press. ISBN 978-1-57230-040-8.
  45. ^ MacEachren, A.M. (1994). Some Truth with Maps: A Primer on Symbolization & Design. University Park: The Pennsylvania State University. ISBN 978-0-89291-214-8. (p. 9)
  46. ^ Monmonier, Mark (1993). Mapping It Out. Chicago: University of Chicago Press. ISBN 978-0-226-53417-6. p. 93
  47. ^ Illustrated Atlas of the World. Rand McNally. 1992. ISBN 978-0-528-83492-9.
  48. ^ Jill Saligoe-Simmel,"Using Text on Maps: Typography in Cartography"
  49. ^ Albrecht, Jochen. "Maps projections". Introduction to Mapping Sciences, 2005. Retrieved 2013-08-13.
  50. ^ Monmonier, Mark (1996). 2nd. (ed.). How to Lie with Maps. Chicago: University of Chicago Press. p. 51. ISBN 978-0-226-53421-3.
  51. ^ Openstreetmap.org Copyright Easter Eggs

Bibliography

Further reading

Mapmaking
  • MacEachren, A.M. (1994). Some Truth with Maps: A Primer on Symbolization & Design. University Park: The Pennsylvania State University. ISBN 978-0-89291-214-8.
  • Monmonier, Mark (1993). Mapping It Out. Chicago: University of Chicago Press. ISBN 978-0-226-53417-6.
  • Kraak, Menno-Jan; Ormeling, Ferjan (2002). Cartography: Visualization of Spatial Data. Prentice Hall. ISBN 978-0-13-088890-7.
  • Peterson, Michael P. (1995). Interactive and Animated Cartography. Upper Saddle River, New Jersey: Prentice Hall. ISBN 978-0-13-079104-7.
  • Slocum, T. (2003). Thematic Cartography and Geographic Visualization. Upper Saddle River, New Jersey: Prentice Hall. ISBN 978-0-13-035123-4.
History
  • Ralph E Ehrenberg (October 11, 2005). Mapping the World: An Illustrated History of Cartography. National Geographic. p. 256. ISBN 978-0-7922-6525-2.
  • J. B. Harley and David Woodward (eds) (1987). The History of Cartography Volume 1: Cartography in Prehistoric, Ancient, and Medieval Europe and the Mediterranean. Chicago and London: University of Chicago Press. ISBN 978-0-226-31633-8.CS1 maint: Extra text: authors list (link)
  • J. B. Harley and David Woodward (eds) (1992). The History of Cartography Volume 2, Book 1: Cartography in the Traditional Islamic and South Asian Societies. Chicago and London: University of Chicago Press. ISBN 978-0-226-31635-2.CS1 maint: Extra text: authors list (link)
  • J. B. Harley and David Woodward (eds) (1994). The History of Cartography Volume 2, Book 2: Cartography in the Traditional East and Southeast Asian Societies. Chicago and London: University of Chicago Press. ISBN 978-0-226-31637-6.CS1 maint: Extra text: authors list (link)
  • David Woodward and G. Malcolm Lewis (eds) (1998). The History of Cartography Volume 2, Book 3: Cartography in the Traditional African, American, Arctic, Australian, and Pacific Societies [Full text of the Introduction by David Woodward and G. Malcolm Lewis]. Chicago and London: University of Chicago Press. ISBN 978-0-226-90728-4.CS1 maint: Extra text: authors list (link)
  • David Woodward (ed) (2007). The History of Cartography Volume 3: Cartography in the European Renaissance. Chicago and London: University of Chicago Press. ISBN 978-0-226-90733-8.CS1 maint: Extra text: authors list (link)
  • Mark Monmonier (ed) (2015). The History of Cartography Volume 6: Cartography in the Twentieth Century. Chicago and London: University of Chicago Press. ISBN 9780226534695.CS1 maint: Extra text: authors list (link)
  • Matthew Edney and Mary S. Pedley (eds). The History of Cartography Volume 4: Cartography in the European Enlightenment. Chicago and London: University of Chicago Press. ISBN 978-0-226-31633-8.CS1 maint: Extra text: authors list (link)
  • Roger J. P. Kain et al. (eds). The History of Cartography Volume 5: Cartography in the Nineteenth Century. Chicago and London: University of Chicago Press.CS1 maint: Extra text: authors list (link)
Meanings
  • Monmonier, Mark (1991). How to Lie with Maps. Chicago: University of Chicago Press. ISBN 978-0-226-53421-3.
  • Wood, Denis (1992). The Power of Maps. New York/London: The Guilford Press. ISBN 978-0-89862-493-9.

External links

45×90 points

The 45×90 points are the four points on earth which are halfway between the geographical poles, the equator, the Prime Meridian, and the 180th meridian.

Atlas

An atlas is a collection of maps; it is typically a bundle of maps of Earth or a region of Earth.

Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geographic features and political boundaries, many atlases often feature geopolitical, social, religious and economic statistics. They also have information about the map and places in it.

Cartography of the United States

Maps of the New World had been produced since the 19th century. The history of cartography of the United States begins in the 18th century, after the declared independence of the thirteen original colonies on July 4, 1776, during the American Revolutionary War (1775-1783). Later, Samuel Augustus Mitchell published a map of the United States in 1867. The National Program for Topographic Mapping was initiated in 2001 by the United States Geological Survey.

Celestial cartography

Celestial cartography, uranography, astrography or star cartography is the fringe of astronomy and branch of cartography concerned with mapping stars, galaxies, and other astronomical objects on the celestial sphere. Measuring the position and light of charted objects requires a variety of instruments and techniques. These techniques have developed from angle measurements with quadrants and the unaided eye, through sextants combined with lenses for light magnification, up to current methods which include computer-automated space telescopes. Uranographers have historically produced planetary position tables, star tables, and star maps for use by both amateur and professional astronomers. More recently computerized star maps have been compiled, and automated positioning of telescopes is accomplished using databases of stars and other astronomical objects.

Coastline paradox

The coastline paradox is the counterintuitive observation that the coastline of a landmass does not have a well-defined length. This results from the fractal-like properties of coastlines, i.e., the fact that a coastline typically has a fractal dimension (which in fact makes the notion of length inapplicable). The first recorded observation of this phenomenon was by Lewis Fry Richardson and it was expanded upon by Benoit Mandelbrot.The measured length of the coastline depends on the method used to measure it and the degree of cartographic generalization. Since a landmass has features at all scales, from hundreds of kilometers in size to tiny fractions of a millimeter and below, there is no obvious size of the smallest feature that should be taken into consideration when measuring, and hence no single well-defined perimeter to the landmass. Various approximations exist when specific assumptions are made about minimum feature size.

The problem is fundamentally different from the measurement of other, simpler edges. It is possible, for example, to accurately measure the length of a straight, idealized metal bar by using a measurement device to determine that the length is less than a certain amount and greater than another amount—that is, to measure it within a certain degree of uncertainty. The more accurate the measurement device, the closer results will be to the true length of the edge. When measuring a coastline, however, the issue is that the result does not increase in accuracy for an increase in measurement —it only increases; unlike with the metal bar, there is no way to obtain a maximum value for the length of the coastline.

Compass rose

A compass rose, sometimes called a windrose or Rose of the Winds, is a figure on a compass, map, nautical chart, or monument used to display the orientation of the cardinal directions (north, east, south, and west) and their intermediate points. It is also the term for the graduated markings found on the traditional magnetic compass. Today, the idea of a compass rose is found on, or featured in, almost all navigation systems, including nautical charts, non-directional beacons (NDB), VHF omnidirectional range (VOR) systems, global-positioning systems (GPS), and similar equipment.

The modern compass rose has eight principal winds. Listed clockwise, these are:

Although modern compasses use the names of the eight principal directions (N, NE, E, SE, etc.), older compasses use the traditional Italianate wind names of Medieval origin (Tramontana, Greco, Levante, etc.)

4-point compass roses use only the four "basic winds" or "cardinal directions" (North, East, South, West), with angles of difference at 90°.

8-point compass roses use the eight principal winds—that is, the four cardinal directions (N, E, S, W) plus the four "intercardinal" or "ordinal directions" (NE, SE, SW, NW), at angles of difference of 45°.

16-point compass roses are constructed by bisecting the angles of the principal winds to come up with intermediate compass points, known as half-winds, at angles of difference of 22​1⁄2°. The names of the half-winds are simply combinations of the principal winds to either side, principal then ordinal. E.g. North-northeast (NNE), East-northeast (ENE), etc.

32-point compass roses are constructed by bisecting these angles, and coming up with quarter-winds at 11​1⁄4° angles of difference. Quarter-wind names are constructed with the names "X by Y", which can be read as "one quarter wind from X toward Y", where X is one of the eight principal winds and Y is one of the two adjacent cardinal directions. For example, North-by-east (NbE) is one quarter wind from North towards East, Northeast-by-north (NEbN) is one quarter wind from Northeast toward North. Naming all 32 points on the rose is called "boxing the compass".

The 32-point rose has the uncomfortable number of 11​1⁄4° between points, but is easily found by halving divisions and may have been easier for those not using a 360° circle. Using gradians, of which there are 400 in a circle, the sixteen-point rose will have twenty-five gradians per point.

Geography

Geography (from Greek: γεωγραφία, geographia, literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and phenomena of the Earth and planets. The first person to use the word γεωγραφία was Eratosthenes (276–194 BC). Geography is an all-encompassing discipline that seeks an understanding of Earth and its human and natural complexities—not merely where objects are, but also how they have changed and come to be.

Geography is often defined in terms of two branches: human geography and physical geography. Human geography deals with the study of people and their communities, cultures, economies, and interactions with the environment by studying their relations with and across space and place. Physical geography deals with the study of processes and patterns in the natural environment like the atmosphere, hydrosphere, biosphere, and geosphere.

The four historical traditions in geographical research are: spatial analyses of natural and the human phenomena, area studies of places and regions, studies of human-land relationships, and the Earth sciences. Geography has been called "the world discipline" and "the bridge between the human and the physical sciences".

Geography and cartography in medieval Islam

Medieval Islamic geography was based on Hellenistic geography and reached its apex with Muhammad al-Idrisi in the 12th century.

Geoinformatics

Geoinformatics is the science and the technology which develops and uses information science infrastructure to address the problems of geography, cartography, geosciences and related branches of science and engineering.

Grid reference

Grid references define locations in maps using Cartesian coordinates. Grid lines on maps define the coordinate system, and are numbered to provide a unique reference to features. This reference is normally based on projected easting and northings

History of cartography

Cartography, or mapmaking, has been an integral part of human history for millions of years. From cave paintings to ancient maps of Babylon, Greece, and Asia, through the Age of Discovery, and on into the 21st century, people have created and used maps as essential tools to help them define, explain, and navigate their way through the world. Maps began as two-dimensional drawings but can also adopt three-dimensional shapes (globes, models) and be stored in purely numerical forms.

The term cartography is modern, loaned into English from French cartographie in the 1840s, based on Middle Latin carta "map".

List of Graeco-Roman geographers

Pre-Hellenistic Classical Greece

Homer

Anaximander

Hecataeus of Miletus

Massaliote Periplus (?)

Scylax of Caryanda (6th century BC)

HerodotusHellenistic periodPytheas (died c. 310 BC)

Periplus of Pseudo-Scylax (4th or 3rd century BC)

Megasthenes (died c. 290 BC)

Autolycus of Pitane (died c. 290 BC)

Dicaearchus (died c. 285 BC)

Deimakos (3rd century BC)

Timosthenes (fl. 270s BC)

Eratosthenes (c. 276-194 BC)

Scymnus (fl. 180s BC)

Hipparchus (c. 190-120 BC)

Agatharchides (2nd century BC)

Posidonius (c. 135-51 BC)

Pseudo-Scymnus (c. 90 BC)

Diodorus Siculus (c. 90-30 BC)

Alexander Polyhistor (1st century BC)Roman Empire period

Periplus of the Erythraean Sea

Strabo (64 BC - 24 AD)

Pomponius Mela (fl. 40s AD)

Isidore of Charax (1st century AD)

Mucianus (1st century AD)

Pliny the Elder (23-79 AD), Natural History

Marinus of Tyre (c. 70-130)

Ptolemy (90-168), Geography

Pausanias (2nd century)

Agathedaemon of Alexandria (2nd century)

Dionysius of Byzantium (2nd century)

Agathemerus (3rd century)

Tabula Peutingeriana (4th century)

Alypius of Antioch (4th century)

Marcian of Heraclea (4th century)

Expositio totius mundi et gentium (AD 350-362)

Julius Honorius (very uncertain: 4th, 5th or 6th century)Byzantine EmpireHierocles (author of Synecdemus) (6th century)

Cosmas Indicopleustes (6th century)

Stephanus of Byzantium (6th century)

Location

In geography, location and place are used to identify a point or an area on the Earth's surface or elsewhere. The term location generally implies a higher degree of certainty than place, the latter often indicating an entity with an ambiguous boundary, relying more on human or social attributes of place identity and sense of place than on geometry.

Map

A map is a symbolic depiction emphasizing relationships between elements of some space, such as objects, regions, or themes.

Many maps are static, fixed to paper or some other durable medium, while others are dynamic or interactive. Although most commonly used to depict geography, maps may represent any space, real or fictional, without regard to context or scale, such as in brain mapping, DNA mapping, or computer network topology mapping. The space being mapped may be two dimensional, such as the surface of the earth, three dimensional, such as the interior of the earth, or even more abstract spaces of any dimension, such as arise in modeling phenomena having many independent variables.

Although the earliest maps known are of the heavens, geographic maps of territory have a very long tradition and exist from ancient times. The word "map" comes from the medieval Latin Mappa mundi, wherein mappa meant napkin or cloth and mundi the world. Thus, "map" became the shortened term referring to a two-dimensional representation of the surface of the world.

Map projection

A map projection is a systematic transformation of the latitudes and longitudes of locations from the surface of a sphere or an ellipsoid into locations on a plane. Maps cannot be created without map projections. All map projections necessarily distort the surface in some fashion. Depending on the purpose of the map, some distortions are acceptable and others are not; therefore, different map projections exist in order to preserve some properties of the sphere-like body at the expense of other properties. There is no limit to the number of possible map projections.More generally, the surfaces of planetary bodies can be mapped even if they are too irregular to be modeled well with a sphere or ellipsoid; see below. Even more generally, projections are a subject of several pure mathematical fields, including differential geometry, projective geometry, and manifolds. However, "map projection" refers specifically to a cartographic projection.

Normalnull

Normalnull ("standard zero") or Normal-Null (short N. N. or NN ) is an outdated official vertical datum used in Germany. Elevations using this reference system were to be marked "Meter über Normal-Null" (“meters above standard zero”). Normalnull has been replaced by Normalhöhennull (short NHN).

Orthographic projection in cartography

The use of orthographic projection in cartography dates back to antiquity. Like the stereographic projection and gnomonic projection, orthographic projection is a perspective (or azimuthal) projection, in which the sphere is projected onto a tangent plane or secant plane. The point of perspective for the orthographic projection is at infinite distance. It depicts a hemisphere of the globe as it appears from outer space, where the horizon is a great circle. The shapes and areas are distorted, particularly near the edges.

Summit

A summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. The topographic terms acme, apex, peak (mountain peak), and zenith are synonymous.

The term top (mountain top) is generally used only for a mountain peak that is located at some distance from the nearest point of higher elevation. For example, a big massive rock next to the main summit of a mountain is not considered a summit. Summits near a higher peak, with some prominence or isolation, but not reaching a certain cutoff value for the quantities, are often considered subsummits (or subpeaks) of the higher peak, and are considered part of the same mountain. A pyramidal peak is an exaggerated form produced by ice erosion of a mountain top. Summit may also refer to the highest point along a line, trail, or route.

The highest summit in the world is Everest with height of 8844.43 m above sea level (29,029 ft). The first official ascent was made by Tenzing Norgay and Sir Edmund Hillary. They reached the mountain`s peak in 1953.Whether a highest point is classified as a summit, a sub peak or a separate mountain is subjective. The UIAA definition of a peak is that it has a prominence of 30 metres (98 ft) or more; it is a mountain summit if it has a prominence of at least 300 metres (980 ft). Otherwise, it's a subpeak.

In many parts of the western United States, the term summit refers to the highest point along a road, highway, or railroad. For example, the highest point along Interstate 80 in California is referred to as Donner Summit and the highest point on Interstate 5 is Siskiyou Mountain Summit.

Symbol

A symbol is a mark, sign or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different concepts and experiences. All communication (and data processing) is achieved through the use of symbols. Symbols take the form of words, sounds, gestures, ideas or visual images and are used to convey other ideas and beliefs. For example, a red octagon may be a symbol for "STOP". On a map, a blue line might represent a river. Numerals are symbols for numbers. Alphabetic letters may be symbols for sounds. Personal names are symbols representing individuals. A red rose may symbolize love and compassion. The variable 'x', in a mathematical equation, may symbolize the position of a particle in space.

In cartography, an organized collection of symbols forms a legend for a map.

Branches
Techniques and tools
Institutions
Education
Visualization of technical information
Fields
Image types
People
Related topics

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.