The central focus of this book is on the theory of map projections. The problem of map projection is stated, and the basic terminology is introduced. The map of massachusetts in unprojected decimal degrees of longitude and latitude note the proportion of the lines and the circle. Since the mass of the earth is not uniform at all points, and the direction of gravity changes, the shape of the geoid is irregular. Planar projections are also called azimuthal because every planar projection preserves the property of azimuthality, directions azimuths from one or two points to all other points on the map. A projection is a way of displaying the earths surface. However, the peters projection must be evaluated separately from its scientific accuracy. He drew his first southup map when he was 12 years old. Stuart mcarthurs universal corrective map part 7 of 14. A map projection is the mathematical transformation of coordinates on a.
Maps in this orientation are sometimes called upside down maps or reversed maps other maps with nonstandard orientation include t and o maps, polar maps, and dymaxion maps. At age 15, after being tormented for coming from the bottom of the world, stuart resolved to one day publish a map with. Mcarthurs universal corrective map of the world has a fabulous history, made by an australian who was tormented for coming from the bottom of the world. This booklet provides a conceptual introduction to map projections and geographic reference systems. Mcarthurs universal corrective map of the world published in 1979 by australian stuart mcarthur challenged eurocentric maps flipped map so australia and southern hemisphere now on top rotated map so australia was in the center of the map. However, to maintain accuracy for largerscale maps scales of 1. In the translation from a spherical surface to a twodimensional, flat surface, a change in the expression of points occurs. A map projection is a way of showing the surface of a threedimensional sphere on a flat surface. What is the importance of map projection in geographic. Pseudoconic projection is one of the oldest map types and although they were used by ptolemy, they are seldom seen today. Geographic perspectivemap projections flashcards quizlet. Map projections are introduced on pages 1012, and pages. To start with they promote the use of peters projection maps in schools.
Get directions, maps, and traffic for mcarthur, oh. Challenging such engrained conventions is a little harder but here, stuart mcarthur achieved just that with a. Map projection involves taking data whose spatial coordinates are defined in terms of latitude and longitude on a curved earth surface and transforming those data so that their spatial coordinates are defined in terms of easting and northing or x,y on a flat map surface. Manual by lev bugayevskiy and john snyder, ball state. The field of map projections concerns itself with the ways of translating the curved surface of the earth into a flat map. His geography teacher told him to redo his assignment with the correct way up if he wanted to pass. After decades of using only one map projection, the polyconic, for its mapping program, the u. A mercator projection comes from the idea of wrapping a piece of paper around a globe to make a cylinder. It was the first modern southup map, published in 1979. Greenland and alaska will appear much larger than they are on a globe. Thus the emphasis on direction, distance, and area preservation. In cartography, a map projection is a way to flatten a globes surface into a plane in order to make a map. The shape of the earth and the geodetic datum concept are covered on pages 46. Map makers attempt to transfer the eartha round, spherical globeto flat paper.
Order the map the hobodyer has south up on one side and north up on the other the whats up. This orthographic projection of the earths surface creates a twodimensional representation of a threedimensional surface. Scale distortions on map projections map projections without distortions would represent the correct. A map projectionis a mathematically described technique of how to represent the earths curved surface on a flat map. Map projection is the method of transferring the graticule of latitude and longitude on a plane surface. A circular economy vision for a competitive europe 5 importantly, the report points out how often many of these changes reinforce each other. Page 79 discuss map scale and the basics of coordinate systems. A datum provides a frame of reference for measuring locations on the surface of the earth. Planar, azimuthal or zenithal projection conic projection cylindrical projection mathematical or.
Mathematical cartography also takes in map scales and their. Mcarthur s universal corrective map of the world has a fabulous history, made by an australian who was tormented for coming from the bottom of the world. A map projections aspect is its orientation on the page or display screen. In doing so, it can be determined that the peters map is not as powerful of a representation of the world as. For larger scale maps, including topographic quadrangles and the state base map series, conformal projections such as the transverse mercator and the lambert conformal conic are. Map projections distortions projection refers to the notion of shining light through the earth surface and projecting latitudes, longitudes and geographic features onto a developable surface. Position your mouse over the map and use your mousewheel to zoom in or out. Given a cylindrical projection, the x scale must increase away from equator.
The projected graticule shown above is the result of an azimuthal equidistant projection in its normal polar aspect. The stereographic map projection is conformal but not. Antiti map projections tn 6 a map is a representation of all or part of the earth drawn on a flat surface at a specific scale. Geological survey usgs now uses several of the more common projections for its published maps. The circle gives the impression that worcester is approximately the same distance from boston as new hampshire, and that the state is nearly five times longer, east to west, as it is. Such a map shows shapes fairly accurately but not size or distance. Putting australia at the top half of a map, as was done in mcarthurs universal corrective map 1979, may seem like the work of some prankster in the outback, but in fact, there is no intrinsic reason to put the southern hemisphere at the bottom. If north or south is straight up, the aspect is said to be equatorial. The first three following map images are odt, reproduced with their permission. A map is a projection of data usually from the real earth.
The stereographic map projection is another ancient projection, dating back to the second century b. Maps and map reading are essential skills that all of the armed forces need. In the process of projection the earth is represented by a model an ellipsoid. Three years later he was an exchange student in japan. This is a digital copy of a book that was preserved for.
To represent parts of the surface of the earth on a flat paper map or on. Map projection definition of map projection by the free. Lecture 2 map projections and gis coordinate systems. It can also be defined as the transformation of spherical. A map projection is a systematic transformation of the latitudes and longitudes of positions on the surface of the earth to a. Maps were devised because they are much easier to use, store, and transport than globes, and they facilitated the development of much larger scaled representations than was the case with a globe.
Mcarthur map created by stuart mcarthur of melbourne, australia. T comes from the cross formed by the mediterranean, the nile and the don danube. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Maps can be presented in any orientation and alignment and projections give us enormous flexibility. Angles, areas, directions, shapes, and distances can become distorted when transformed from a curved surface to a plane. A map projection is used to portray all or part of the round earth on a flat surface. The tracking of materials, components, and products eases the shift from ownership to new business models with flexible and affordable access to valueadded services. The geoid is defined as the surface of the earths gravity field, which is approximately the same as mean sea level. Types of map projections many types of map projections are being used for map making. When the central axis of the developable surface is oriented eastwest, the projections aspect is transverse. Stuart mcarthur drew his first southup map when he was 12 years old.
A tutorial on map projections and geographic coordinate systems. Circumference of lines of latitude getting smaller, maps width staying constant. The orthographic projection distorts distance, shape, and the size of areas. A map projection is the mathematical transformation of coordinates on one surface, in our case the ellipsoidal reference surface of the earth, to coordinates on the projection plane. Theories from differential geometry are particularized for the transformation from a sphere or spheroid as the model of the earth onto a selected plotting surface. Because there is no limit to the number of possible map projections, there can be no comprehensive list. It also provides its information in a wellorganized manner. A map projection is a rigorous mathematical means of translating a particular region of our earths curvaceous threedimensional surface into a flat twodimensional representation. They are basically classified into four groups in accordance with the map projection theory or the types of surfaces that are tangent with the globe. Challenging such engrained conventions is a little harder but here, stuart mcarthur achieved just that with a relatively sparse yet stark representation. This means different y scales in different parts of the map what is the xscale factor. Jerusalem is at the center and the three continents represent the trinity.
A sound knowledge of map projections and grids requires an understanding of the mathematical nature of projections and the size and shape of the earth, since in our context. So map projections are chosen based on the purposes of the map. This requires a systematic transformation of the latitudes and longitudes of locations from the surface of the globe into locations on a plane. He drew his first southup map when he was 12 years old 1970. The stereographic map projection is most useful for maps of polar regions for navigation purposes or large continentsized areas of similar extent in all directions. Map projection concerns the science of mathematical cartography, the techniques by which the earths dimensions, shape and features are translated in map form, be that twodimensional paper or two or three dimensional electronic representations.
This is a summary of map projections that have articles of their own on wikipedia or that are otherwise notable. In all the map projections we will be dealing with, the datum surface is a 3dimensional surface, either a sphere or ellipsoid, representing the earth. Understanding map projections landing page for kartoweb. The importance of map projections by sarah lyle on prezi. Start studying geographic perspectivemap projections.
Tobler university of california santa barbara, usa since the time of ptolemy 2000 years ago the objective of map projections has been to produce maps of high metric fidelity, and this is still the prime objective today. Armed forces military maps show the earth drawn to scale as you would see it from above the military uses the universal transverse mercator utm and the universal polar stereographic ups grid system. All projections of a sphere on a plane necessarily distort the surface in some way and to some extent. Map projections are the different techniques used by cartographers for presenting a round globe on a flat surface. Between those scales, choosing to use a sphere or spheroid will depend on the maps purpose and the accuracy of the data. It is perpendicular to the direction of gravity pull. In cartography, a map projection is a way to flatten a globes surface into a plane in order to. Although the projection procedure inevitably introduces systematic spatial distortions, particular types of distortion can be minimized to suit the geographic scope and intended use of the map data. Usgs topographic map based on the transverse mercator projection is nearly correct in every respect. The problem with projections is that they change the surface in some way. Arcview permits data to be viewed in various map projections but no new. Southup map orientation is the orientation of a map with south up, or at the top of the map, amounting to a 180degree rotation of the map from the standard convention of northup. Depending on the purpose of the map, some distortions may be less bad.
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