Map projection - Metric properties of maps

Many properties can be measured on the earth's surface independently of its geography. Some of these properties are: Area Shape Direction Bearing Distance Scale Map projections can be constructed to preserve one or some of these properties, though not all of them simultaneously. Each projection preserves or compromises or approximates basic metric properties in different ways. The purpose of the map, then, determines which projection should form the base for the map. Since many purposes exist for maps ...

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Map projection, Map projection - Metric properties of maps, Map projection - Construction of a map projection, Map projection - Choosing a projection surface, Map projection - Orientation of the projection, Map projection - Scale, Map projection - Choosing a model for the shape of the Earth, Map projection - Classification, Map projection - Projections by surface, Map projection - Cylindrical, Map projection - Pseudocylindrical, Map projection - Conical, Map projection - Pseudoconical, Map projection - Azimuthal projections onto a plane, Map projection - Projections by preservation of a metric property, Map projection - Conformal, Map projection - Equal-area, Map projection - Equidistant, Map projection - Gnomonic, Map projection - Retroazimuthal, Map projection - Compromise projections, Map projection - Other noteworthy projections

Read more here: » Map projection: Encyclopedia II - Map projection - Metric properties of maps

Map projection - Cylindrical. The term "cylindrical projection" is used to refer to any projection in which meridians are mapped to equally spaced vertical lines and circles of latitude (parallels) are mapped to horizontal lines (or, mutatis mutandis, more generally, radial lines from a fixed point are mapped to equally spaced parallel lines and concentric circles around it are mapped to perpendicular lines). The mapping of meridians to vertical lines can be visualized by imagining a cylinder (of which the ...

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Map projection, Map projection - Metric properties of maps, Map projection - Construction of a map projection, Map projection - Choosing a projection surface, Map projection - Orientation of the projection, Map projection - Scale, Map projection - Choosing a model for the shape of the Earth, Map projection - Classification, Map projection - Projections by surface, Map projection - Cylindrical, Map projection - Pseudocylindrical, Map projection - Conical, Map projection - Pseudoconical, Map projection - Azimuthal projections onto a plane, Map projection - Projections by preservation of a metric property, Map projection - Conformal, Map projection - Equal-area, Map projection - Equidistant, Map projection - Gnomonic, Map projection - Retroazimuthal, Map projection - Compromise projections, Map projection - Other noteworthy projections

Read more here: » Map projection: Encyclopedia II - Map projection - Projections by surface

Map projection - Conformal. Conformal map projections preserve angles locally: Mercator Stereographic Lambert conformal conic Map projection - Equal-area. These projections preserve area: Gall orthographic (also known as Peters projection) Albers conic Lambert azimuthal equal-area Mollweide Briesemeister Sinusoidal Werner Bonne Bottomley Goode's homolosineSee also:

Map projection, Map projection - Metric properties of maps, Map projection - Construction of a map projection, Map projection - Choosing a projection surface, Map projection - Orientation of the projection, Map projection - Scale, Map projection - Choosing a model for the shape of the Earth, Map projection - Classification, Map projection - Projections by surface, Map projection - Cylindrical, Map projection - Pseudocylindrical, Map projection - Conical, Map projection - Pseudoconical, Map projection - Azimuthal projections onto a plane, Map projection - Projections by preservation of a metric property, Map projection - Conformal, Map projection - Equal-area, Map projection - Equidistant, Map projection - Gnomonic, Map projection - Retroazimuthal, Map projection - Compromise projections, Map projection - Other noteworthy projections

Read more here: » Map projection: Encyclopedia II - Map projection - Projections by preservation of a metric property

Map projection - Conformal. Conformal map projections preserve angles locally: Mercator Stereographic Lambert conformal conic Map projection - Equal-area. These projections preserve area: Gall orthographic (also known as Peters projection) Albers conic Lambert azimuthal equal-area Mollweide Briesemeister Sinusoidal Werner Bonne Bottomley Goode's homolosineSee also:

Map projection, Map projection - Metric properties of maps, Map projection - Construction of a map projection, Map projection - Choosing a projection surface, Map projection - Orientation of the projection, Map projection - Scale, Map projection - Choosing a model for the shape of the Earth, Map projection - Classification, Map projection - Projections by surface, Map projection - Cylindrical, Map projection - Pseudocylindrical, Map projection - Conical, Map projection - Pseudoconical, Map projection - Azimuthal projections onto a plane, Map projection - Projections by preservation of a metric property, Map projection - Conformal, Map projection - Equal-area, Map projection - Equidistant, Map projection - Gnomonic, Map projection - Retroazimuthal, Map projection - Compromise projections, Map projection - Other noteworthy projections

Read more here: » Map projection: Encyclopedia II - Map projection - Projections by preservation of a metric property

A fundamental projection classification is based on type of projection surface onto which the globe is conceptually projected. The projections are described in terms of placing a gigantic surface in contact with the earth, followed by an implied scaling operation. These surfaces are cylindrical (e.g., Mercator), conic (e.g., Albers), and azimuthal or plane (e.g., stereographic). Many mathematical projections, however, do not neatly fit into any of these three conceptual projection methods. Hence other peer categories have been described in the literature, such as pseudoconic, pseudocylindrical ...

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Map projection, Map projection - Metric properties of maps, Map projection - Construction of a map projection, Map projection - Choosing a projection surface, Map projection - Orientation of the projection, Map projection - Scale, Map projection - Choosing a model for the shape of the Earth, Map projection - Classification, Map projection - Projections by surface, Map projection - Cylindrical, Map projection - Pseudocylindrical, Map projection - Conical, Map projection - Pseudoconical, Map projection - Azimuthal projections onto a plane, Map projection - Projections by preservation of a metric property, Map projection - Conformal, Map projection - Equal-area, Map projection - Equidistant, Map projection - Gnomonic, Map projection - Retroazimuthal, Map projection - Compromise projections, Map projection - Other noteworthy projections

Read more here: » Map projection: Encyclopedia II - Map projection - Classification

Projection construction is also affected by how the shape of the earth is approximated. In the following discussion on projection categories, a sphere is assumed. However, the Earth is not exactly spherical but is closer in shape to an oblate ellipsoid, a shape which bulges around the equator. Selecting a model for a shape of the earth involves choosing between the advantages and disadvantages of a sphere versus an ellipsoid. Spherical models are useful for small-scale maps such as world atlases and globes, since the error at that scale is n ...

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Map projection, Map projection - Metric properties of maps, Map projection - Construction of a map projection, Map projection - Choosing a projection surface, Map projection - Orientation of the projection, Map projection - Scale, Map projection - Choosing a model for the shape of the Earth, Map projection - Classification, Map projection - Projections by surface, Map projection - Cylindrical, Map projection - Pseudocylindrical, Map projection - Conical, Map projection - Pseudoconical, Map projection - Azimuthal projections onto a plane, Map projection - Projections by preservation of a metric property, Map projection - Conformal, Map projection - Equal-area, Map projection - Equidistant, Map projection - Gnomonic, Map projection - Retroazimuthal, Map projection - Compromise projections, Map projection - Other noteworthy projections

Read more here: » Map projection: Encyclopedia II - Map projection - Choosing a model for the shape of the Earth

The creation of a map projection involves three steps: Selection of a model for the shape of the earth or planetary body (usually choosing between a sphere or ellipsoid) Transformation of geographic coordinates (longitude and latitude) to plane coordinates (eastings and northings or x,y) Reduction of the scale (it does not matter in what order the second and third steps are performed) Because the real earth's shape is irregular, information is lost in the first step, in which an approximating, regular model is chosen. Reducing the scale may be considered to b ...

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Map projection, Map projection - Metric properties of maps, Map projection - Construction of a map projection, Map projection - Choosing a projection surface, Map projection - Orientation of the projection, Map projection - Scale, Map projection - Choosing a model for the shape of the Earth, Map projection - Classification, Map projection - Projections by surface, Map projection - Cylindrical, Map projection - Pseudocylindrical, Map projection - Conical, Map projection - Pseudoconical, Map projection - Azimuthal projections onto a plane, Map projection - Projections by preservation of a metric property, Map projection - Conformal, Map projection - Equal-area, Map projection - Equidistant, Map projection - Gnomonic, Map projection - Retroazimuthal, Map projection - Compromise projections, Map projection - Other noteworthy projections

Read more here: » Map projection: Encyclopedia II - Map projection - Construction of a map projection

A surface that can be unfolded or unrolled into a flat plane or sheet without stretching, tearing or shrinking is called a 'developable surface'. The cylinder, cone and of course the plane are all developable surfaces. Unfortunately, the sphere and ellipsoid are not developable surfaces. Any projection that attempts to project a sphere (or an ellipsoid) on a flat sheet will have to distort the image (similar t ...

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Map projection, Map projection - Metric properties of maps, Map projection - Construction of a map projection, Map projection - Choosing a projection surface, Map projection - Orientation of the projection, Map projection - Scale, Map projection - Choosing a model for the shape of the Earth, Map projection - Classification, Map projection - Projections by surface, Map projection - Cylindrical, Map projection - Pseudocylindrical, Map projection - Conical, Map projection - Pseudoconical, Map projection - Azimuthal projections onto a plane, Map projection - Projections by preservation of a metric property, Map projection - Conformal, Map projection - Equal-area, Map projection - Equidistant, Map projection - Gnomonic, Map projection - Retroazimuthal, Map projection - Compromise projections, Map projection - Other noteworthy projections

Read more here: » Map projection: Encyclopedia II - Map projection - Choosing a projection surface

A globe is the only way to represent the earth with the same scale throughout the entire map surface and in all directions. For a flat map this is not even possible across an area of any extent. Thus, on a flat map, properties of constant scale are always limited. Possible properties are: The scale depends on location, but not on direction; this is equivalent with preservation of angles: conformal map For a given latitude and direction, the scale is the same everywhere; this applies for any cylindrical pro ...

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Map projection, Map projection - Metric properties of maps, Map projection - Construction of a map projection, Map projection - Choosing a projection surface, Map projection - Orientation of the projection, Map projection - Scale, Map projection - Choosing a model for the shape of the Earth, Map projection - Classification, Map projection - Projections by surface, Map projection - Cylindrical, Map projection - Pseudocylindrical, Map projection - Conical, Map projection - Pseudoconical, Map projection - Azimuthal projections onto a plane, Map projection - Projections by preservation of a metric property, Map projection - Conformal, Map projection - Equal-area, Map projection - Equidistant, Map projection - Gnomonic, Map projection - Retroazimuthal, Map projection - Compromise projections, Map projection - Other noteworthy projections

Read more here: » Map projection: Encyclopedia II - Map projection - Scale