Map projections are important in creating maps with map projections distorting the surface in some way. Type of projection[ edit ] Cylindrical In standard presentation, these map regularly-spaced meridians to equally spaced vertical lines, and parallels to horizontal lines.
Hence other peer categories have been described in the literature, such as pseudoconic, pseudocylindrical, pseudoazimuthal, retroazimuthal, and polyconic. Transformation of geographic coordinates longitude and latitude to Cartesian x,y or polar plane coordinates.
The following sections describe and illustrate how the cylindrical, conic, and azimuthal families of map projections are constructed and provides some examples of projections that are based on them. Interrupted Projection There are many different types of interrupted projection maps.
There is great distortion towards the borders of the map. Distortion can be reduced by "interrupting" the map. Distortion increases with distance from the point or line of tangency. This is not the case for most projections, which are defined only in terms of mathematical formulae that have no direct geometric interpretation.
Scale distortions on maps are shown on the map by an ellipse of distortion or using scale factor which is the ratio of the scale at a given point to the true scale.
Is rectangular; Has straight vertical meridians, spaced evenly; Has straight parallels symmetrically placed about the equator; Has parallels constrained to where they fall when light shines through the globe onto the cylinder, with the light source someplace along the line formed by the intersection of the prime meridian with the equator, and the center of the sphere.
Globes are not suitable for use at large scales, such as finding directions in a city or following a hiking route, where a more detailed image is essential. Such a cylindrical projection for example is one which: Click here to see To view all translated materials including this page, select Country from the country navigator on the bottom of this page.
The type of projection and the properties preserved by the projection use the following categories: Normal cylindrical projections map the whole Earth as a finite rectangle, except in the first two cases, where the rectangle stretches infinitely tall while retaining constant width.
Data sets are geographic information; their collection depends on the chosen datum model of the Earth.
Some possible properties are: Such lines of true scale are called standard lines. Today, it is usually the job of the cartographer or editor to choose a suitable map projection, taking into account the purpose of the map.
They are expensive to produce, especially in varying sizes scales. For irregular planetary bodies such as asteroidshowever, sometimes models analogous to the geoid are used to project maps from.
At places on map where the surface is outside the globe, features appear larger than in reality and scale factor is greater than 1. A classic example of area exaggeration is the comparison of land masses on the map, where for example Greenland appears bigger than South America and comparable in size to Africa, while in reality it is about one-eight the size of S.
The east-west scale matches the north-south scale: The ellipsoidal model is commonly used to construct topographic maps and for other large- and medium-scale maps that need to accurately depict the land surface.
This means great circles through the central point are represented by straight lines on the map. This is not the case for most projections, which are defined only in terms of mathematical formulae that have no direct geometric interpretation.
The purpose of the map determines which projection should form the base for the map. However, the further we travel down the map, the more distorted and less accurate the map becomes. Van der Grinten projection preserves the image of Mercator projection and reduces its distortion.
Retroazimuthal Direction to a fixed location B by the shortest route corresponds to the direction on the map from A to B. This scale can be measured as the ratio of distance on the globe to the corresponding distance on the Earth. While the first step inevitably distorts some properties of the globe, the developable surface can then be unfolded without further distortion.
There are also projections Maurer's Two-point equidistant projectionClose where true distances from two points are preserved. Some of the simplest map projections are literal projections, as obtained by placing a light source at some definite point relative to the globe and projecting its features onto a specified surface.
types of map projections and their characteristics, with examples given using maps from the GIS Research & Map Collection, University Libraries. Map Projection Types.
Cylindrical Projection. A cylindrical projection map is the most common type of map that we see. Imagine placing the movie screen around the globe in a cylinder shape. Mapmakers have developed hundreds of map projections, over several thousand years. Three large families of map projection, plus several smaller ones, are generally acknowledged.
These are based on the types of geometric shapes that are used to transfer features from a sphere or spheroid to a plane. It turns out Monday was Steve Waterman's birthday.
His site has posters of his map, plus maybe the world's only Winkel Tripel-critiquing poetry. 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.
Learn about the different types of map projections and the different projection techniques that mapmakers use, including the Mercator projection.Map projections types