Also called Sanson-Flamsteed or Mercator equal area projection. As its full name implies, the Lambert projection is conformal, and thus it cannot be equivalent . The point is usually a Pole, but this is not essential. Poles are represented as arcs rather than as single points. An example would be the classification conformal conic projection with two standard parallels having the meaning that the projection is a conformal map projection, that the intermediate surface is a cone, and that the cone intersects the ellipsoid (or sphere) along two parallels; i.e. Distortion values are the same along a particular parallel. Here are some well-known projections described and illustrated. Azimuthal (or zenithal or planar) projections are made upon a plane tangent (or secant) to the reference surface. In the polar aspect the meridians are equally spaced straight Scale distortions on a tangent map surface. Distortions All projections result in some distortion of the relationships between features on the sphere when they are projected onto a flat surface. This map uses the same settings as the previous World Map, but it is more typical of a Conic Projection map. Meridians are equally spaced. area distortions are often reasonably well preserved. Note the size of Greenland and Africa below. Extensively used for large-scale mapping of regions predominantly east-west in extent. The Lambert conformal conic map projection is typically based on two standard parallels, but it can also be defined with a single standard parallel and a scale factor. covers the area 168 - 162W (zone number 3), and 0 - 8N (letter N The projection is also known as the Gauss-Krger or Gauss conformal. of great transoceanic voyaging, there was a need for conformal navigation Shape and Ney modified conformal conic parameters are as follows: Ney, C. H. (1949). (like a source of light rays), is the centre of the Earth. 3.Universal Tranverse Mercator (UTM) projection: The Universal Transverse Mercator (UTM) projection uses a transverse cylinder, secant to the reference surface (figure below). Directions, angles, and shapes are maintained at infinitesimal scale. It is available in. The first Cylindrical Projections developed had the lines of latitude and lines of longitude shown as straight lines see the section on theMercator projection. are shown as straight lines, originating at the pole, intersecting Mapping onto a 2D mapping plane means transforming each point on the reference surface with geographic coordinates (f,l) to a set of Cartesian coordinates (x,y) representing positions on the map plane (figure below). Only one hemisphere can be shown. All areas are proportional to the same areas on the earth. (There is an element of assumption that a projection is cylindrical if not otherwise stated.). These do, however, have rather noticeable shape distortions. It divides the world into 60 narrow longitudinal zones of 6 degrees. Conic projections are used for midlatitude zones that have an east-west orientation. Modifications are called sinusoidal interrupted and sinusoidal 3x interrupted. Somewhat more complex Conic projections contact the global surface at two locations. For the stereographic this point is the opposite pole to the point of tangency, and for the orthographic the perspective point is an infinite point in space on the The line of latitude where the cone touches the Earth is called a Standard Parallel. Parallels The only projection which has all features with no distortion is a globe. They give useful maps of mid-latitudes for countries which have no great extent in latitude. It is of little use for world maps because of the distortions. Conic. Typically the first standard parallel is set to either 71 or 74 north or south and the other standard parallel is set to 89 59' 58" (89.99944444). The distortion properties of map are typically classified according to what is not distorted on the map: A particular map projection can have any one of these three properties. For navigation, this is the easiest route to follow, but not necessary the shortes route (figure below). and the equidistant projections of the same class will provide a very a certain direction, is seldom desired. a useful compromise between the conformal and equal-area maps. scale increases rapidly with the distance from the center. Tennessee is much larger east/west than north/south. The distortion increase rapidly away from the central meridian. However, the distance distortions are extreme. The mathematics in different projections attempt to overcome this problem but none remove all distortions. The Ney modified Lambert conformal conic projection does not project the opposite pole. Like all projections, Mercator takes the spherical coordinate values (latitude and longitude) and "projects" them onto a flat surface. This is not a simple as it sounds. Image courtesy of A B van Brakel, Wikimedia commons. However, the map user Note how the shapes of land masses near the Standard Parallel are fairly close to the true shape when viewed from space see the images at the beginning of this section. Distortion Along Lines of Latitude and Longitude (Distance Distortion). distance and direction distortions are extreme, but all. This projection is best suited for land masses extending in an Both shape and area are reasonably well preserved with the exception of the polar regions. Areas increase with distance from the projection Used for simple portrayals of the world or regions with minimal geographic data such as index maps. Further widely used for topographic maps. The Snyder, J. P. and Voxland, P. M. (1989). It is best suited for maps of continents or regions that are equally extended in all directions from the centre, such as Asia and the Pacific ocean. and Lambert's cylindrical equal-area projection. Although neither shape nor linear scale is truly correct, the distortion of these properties is minimized in the region between the standard parallels. Scale distortions on a secant map surface. The Mercator projection is a cylindrical map projection with a conformal property. R.A. Knippers. The projection is also known as the. A subdivision may be made into perspective and non-perspective azimuthal projections. The distortion property of the map projection is therefore conformal (e.g. Although Greenland is only one-eighth the size of South America, Greenland appears to be larger (figure below). The use of minimum-error or angles on the basis of measurements taken from these maps. Distortion values are the same along a particular parallel. An Albers projection shows areas accurately, but distorts shapes. the projection, such as Mercator, Lambert, Robinson, Cassini etc., but Scale distortions on a map can also be shown by means of a scale a conformal cylindrical projection using a secant cylinder so it meets no distortion in north-south direction). A variant of Lambert azimuthal equal-area. Azimuthal (or planar) are good for areas near the poles. Because of the distortions it is of little use for world maps. Every circle is plotted as circle or an ellipse or, in extreme cases, No limitations on the eastwest range. planes. Both shape and area are reasonably well preserved. The cylindrical projection is best for a rectangular area and a conic projection for a triangular area (figure below). zone numbering system. s a normal cylindrical projection. This projection is best suited for land masses extending in an east-to-west orientation rather than those lying north to south. Thus, the route of constant direction between two locations is a always a straight line. Area, distance, and scale distortions grow rapidly with the distance from the standard parallels. Choosing a cone that touches the earth at about 36 degrees of north latitude would be a good choice for producing a map of Tennessee. E.g. 2, More than 250,000 words that aren't in our free dictionary, Expanded definitions, etymologies, and usage notes. cylindrical projection, the projection surface is tangent or secant at The Werner projection is a variant of Bonne's projection with the standard parallel at the North or South pole. Somewhat more complex Conic projections contact the global surface at two locations. Every map must begin, either consciously or unconsciously, Used for simple portrayals of the world or regions with minimal geographic data such as index maps. The scale is constant along any circle having its centre navigation. Map is equal area. 'equal-area' projections preserve true areas, 'conformal' projections preserve true shape. The selected right circular cone can be secant or tangent to the reference ellipsoid. The parallel spacing increases When 'thingamajig' and 'thingamabob' just won't do, A simple way to keep them apart. These are: This would amount to the projection of the figure above (conical projection with a secant projection plane). the equator. and is still in use today when a simple, straight course is needed for In the normal aspect, they are excellent for mid-latitude aeronautical charts, topographic maps) often make use of a conformal map projection. straight (figure below). iv. It is adapted in France and recommended to the European Commission for conformal pan-European mapping at scales smaller or equal to 1:500,000. Chicago and London: University of Chicago There is no one perfect projection and a map maker must choose the one which best suits their needs. For example, this projection is used for mapping the Malaysian peninsula and the Alaska State, zone 5001 (figure section 4.4). In general, distortion increases north and south of the standard parallel. It's wise to orient the centre of the map at the point of interest (figure below), since scale distortions increase rapidly away from the centre of the gnomonic map projection and the direction of the shortest route (azimuth) is shown by a straight line from the centre of the map only (this applies to all azimuthal maps). This projection often serves as a compromise between Lambert conformal conic and Albers equal-area conic projections. on a map. educational notes, ITC, Enschede, 1998. A version of the Transverse Mercator, but one with a The nominal map scale (given map scale) divided by the scale factor will give the actual scale. Projections. Accessed on April 19, 2021. https://earth-info.nga.mil/. appear to be as large as South America when, in fact, it is only one eight Area, distance, and scale distortions grow rapidly with the distance from the standard parallels. On a world map, the scale variations are evident where landmasses The sole projection used for large scale mapping of the United States by the USGS until the 1950's. 2 adjacent UTM-zones of 6 degrees To represent parts of the surface of the Earth on a flat paper map or on a computer screen, the curved horizontal reference surface must be mapped onto the 2D mapping plane. This shows that while Alber's maintains area, it does so at the cost of distance distortion. Maps are one of the worlds oldest types of document. The oblique aspect is frequently used for world or air-route maps centered on important cities and occasionally for maps of continents. An example, Greenland appears to be larger but is only one-eighth the size of South America. A scale factor of 0.99960 is given to the central meridian of a UTM zone. The Lambert conformal conic projection is best suited for conformal mapping of land masses in mid-latitudes extending in an east-to-west orientation rather than those trending north-to-south. Examples are the Bonne and Werner projection. E.g. Any straight line drawn on this projection represents an actual compass bearing. A further elaboration is the polyconic projection, which deploys a family of tangent or secant cones to bracket a succession of bands of parallels to yield even less scale distortion. It is usually measured as an angle. thedistancebetween a feature and surrounding features Once the class and aspect of the map projection constant direction are shown as straight lines it assist navigators and Two other well-known normal cylindrical projections are the equidistant cylindrical (or Plate Carre) projection If only one standard parallel is set to a pole, the resulting projection is also the stereographic projection in polar aspect, but the second standard parallel presents the circular arc with no scale distortion. Transverse form (transverse cylinder) of the Mercator projection. These two are examples of Azimuthal Projection maps which are not centred on a Pole. stereographic and orthographic (source: ESRI). Compromise between Mercator and other cylindrical projections. The transverse case and occasionally the oblique case of the Mercator projection are used Both shape and area are reasonably well preserved. projection. Because of the distortions away from the Standard Parallel, Conic Projections are usually used to map regions of the Earth particularly in mid-latitude areas. For this projection, the maximum scale distortion for the 48 states is 1.25 percent. Two well known non-perspective azimuthal projections Conic projections are used frequently for mapping large areas (e.g., states, large countries, or continents). The first uses only one Standard Parallel and the second uses two Standard Parallels. purpose (distortion may not be an issue, but keeping equal-areas or true direction may be important). Also in use are the stereographic (the Netherlands) and even non-conformal projections such as Cassini The Albers equal-area conic projection, or Albers projection (named after Heinrich C. Albers), is a conic, equal area map projection that uses two standard parallels. distribution maps and do not contain the noticeable distortions of the Snyder, J. P. (1987). This projection was rarely used before the First World War but is now commonly used for official topographic mapping around the world. These seven images are viewed over the Equator. projections is however exceptional. Simple conic (or equidistant conic) projection (standard parallel 15 degrees North). (conical projection with a secant projection plane). This is called the aspect of a map projection. An equidistant map, in which the scale is correct along Geometric Aspects of Mapping. Also suited for regions extending equally in all directions from a center point, such as Asia and the Pacific Ocean. Projections. States Government Printing Office. Distortion along the parallels and meridians (left), in area (center), and in form (right). There is no distortion along the standard parallels. educational notes, ITC, Enschede, 1999. at the projection centre, but increases moderately with distance Geological Survey Professional Paper 1395. In the 15th, 16th and 17th centuries, during the time have been developed, each with its own specfic qualities. The projection is not conformal at the poles. Lambert Conformal Conic Projections. The. maps such as the Mercator. Two Thousand Years Probably one of the best known cylindrical projection is, . For the gnomonic projection, the perspective point For the, the perspective point All areas, shapes and angles are greatly distorted. any country would either be an azimuthal, cylindrical, or conic projection, The whole UTM grid system uses 60 horizontally oriented cylinders secant to the globe. Lambert Conformal Conic projection (standard parallels 10 and 30 degrees North). U.S. The UTM divides the world into 60 narrow. It does not maintain true directions, but angles and shapes are maintained at infinitesimal scale. or American polyconic (Hassler, 1820). The azimuthal stereographic projection is a conformal projection. charts. The other pole projects to infinity and cannot be shown. The Lambert Conformal Conic projection is one of the best projections for middle latitudes with an east-west orientation. The lines of intersection (standard parallels) are selected at one-sixth below and above the limit of the mapping area. This disadvantage makes the projection unsuitable for large areas on a single sheet. A, of a point on the curved reference surface to a set of planar Cartesian coordinates (. distribution maps. Spacing gradually increases away from the pole. of the size. A projection can only be equidistant (true to scale) at certain places or in certain directions. However, shapes and distances were distorted. Four well-known normal conical projections are the. This is a larger scale than the nominal map scale. Distortion in size and area near the projection limit appears more realistic than almost any other projection. match to the purpose of the map. They are typically used to map the world in its entirety. The three possible apects are normal, transverse and oblique. The, was originally designed to display accurate compass bearings for sea travel. projected as concentric circles centered at the pole. Map is neither conformal nor equal area, but each parallel is true to scale. Also known as simple cylindrical or Plate Carre. All the meridians are equally spaced straight lines converging to a common point. Beyond the Equator you need to twist your point of view to look directly at the area you are interested in. Both shape and area are reasonably well preserved with the exception of the polar regions. Commonwealth of Australia on behalf of ICSM, Standards for rural and urban addressing (AS4819), PSMAs Geocoded National Address File (G-NAF), The Australian Geospatial Reference System, 3D Cadastral Survey Data Exchange Program, Australia and New Zealand Working Group on Place Names, Electronic Lodgement and Transfer of Survey Data Working Group, SIDA Special Interest Group Spatial Information Delivery and Access, Fundamentals of Land Ownership, Land Boundaries and Surveying, Standard Parallels (or Central Meridians), http://egsc.usgs.gov/isb//pubs/MapProjections/projections.html, http://www.csiss.org/map-projections/index.html/, http://www.galleryofmapprojections.com/images/Aust_Centered_2009.jpg, http://www.galleryofmapprojections.com/gedymin/gedymin_prof_11x17.pdf, http://www.genekeyes.com/B.J.S._CAHILL_RESOURCE.html, http://www.geo.hunter.cuny.edu/mp/index.html, http://mathworld.wolfram.com/MapProjection.html, Upgrades to the Australian Geospatial Reference System, have distortions increasing away from the central point, have very small distortions near the centre point (the touch point of the paper), compass direction is only correct from the centre point to another feature not between other features, are fan shaped when used to map large areas, have distortions increasing away from the central circular line (the touch point of the paper), have very small distortions along the central circular line (the touch point of the paper), shapes are shown correctly, but size is distorted. along the main axis of the country or the area of interest. Distortion is small up until about 25 to 30 from the pole. The UTM zone numbering system (click It displays all great circles as straight lines, resulting in any straight line segment showing the. conical. Areas with a lot of distortion are color-coded in red while those with little are color-coded in green. These maps may have Google Earth shows the Earth as it looks from an elevated platform such as an airplane or orbiting satellite. is a useful projection for defining routes of navigation for sea and air travel, because. Now that we know that the Earths surface is curved in a specific way, we know that a map is in fact a flattened representation of some part of the planet. These true direction lines are. Distortion in size and area near the projection limit appears more realistic than almost any other projection. Locally true along the standard parallels. onto cones tangent to each parallel, so the meridians are curved, not positions north of the equator, and a (false) no distortion in North-South direction) we say that the map is equidistant along the meridians (e.g. property depends largely on the purpose of the map. no distortion in North-South direction). to be recognized. It represents areas correctly and has reasonable shape distortions in the region between the standard parallels as compared with the noticeable distortions of the Lambert's equal-area conic projection with one standard parallel. Examples are Goode's projection (an interrupted Mollweide projection) or the interrupted Sanson-Flamsteed projection. The Mercator projection is a normal cylindrical projection. Version 3.8 (2019). Pseudo-cylindrical projection. The images of the Earth as it might be seen from space, gives a good indication of the complexity of the problem facing map makers when it comes to converting the surface of a sphere on to a flat piece of paper. The projection is a derivation from the simple conic projection, but with every parallel true to scale (similar to the Bonne's equal-area projection). projection is a planar projection with a conformal property. Interrupted projections show the globe in one sheet with interrupted forms of graticules. Relevance to GIS B. DISTORTION PROPERTIES Tissot's Indicatrix Conformal (Orthomorphic) Equal area (Equivalent) Equidistant C. FIGURE OF THE EARTH 1. It is available in ArcGIS Pro 1.0 and later and in ArcGIS Desktop 10.0 and later. Angles and shapes (of small areas) are shown correctly, as a result of conformality. Only one hemisphere can be shown. The centre of the projection is oriented at Amsterdam airport to show correct distances (and directions) from this point to the other airports. Polar stereographic azimuthal projection with Conic: The conic tangent case: The conic secant case: Standard parallels are where the cone touches or slices through the globe. To save this word, you'll need to log in. Used for topographic maps at scales from 1: 20,000 to 1: 250,000. For example J.H.Lambert described half a dozen projections. Map is equal area. show shapes correctly, but size is distorted. from the centre. cases. Four well-known normal conical projections are the Lambert The parallels and both poles are represented as circular arcs which are equally spaced and centered on the point of convergence of the meridians. The cylindrical equal-area projection after Lambert is a cylindrical map projection with an equal-area property. standard parallels) could be by determining the range in latitude in degrees north to south and dividing this range by six. nor equal-area and no point is free of distortion, but the distortions Map projections can be described in terms of their: i. The mapping platform for your organization, Free template maps and apps for your industry. The area distortions are significant towards the polar regions. Now note this diagram where the paper doesnt touch the Earth it slices the Earth. The ellipse of distortion, also known Description The equidistant, or simple, conic projection preserves distances along all meridians and two standard parallels. Mainly used for educational purposes. The UTM divides the world into 60 narrow longitudinal zones of 6 degrees, numbered from 1 to 60.
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