The position of a point in a 2D or 3D surface is defined by a system of coordinates.There are mainly three types of Coordinate Systems that you can use to represent the position of the point :
1.Geographic Coordinate System(GCS) : In this type of systems Latitutde and Longitude are used to represent the position of a point in a 3D surface.The surface (like sphere or spheroid or ellipsoid) which mimics the real shape of the World(referred as Geoid) is also known as Reference Surface.The real surface of the earth is very hard to predict due to its undulations and thus represented by a form of common shapes like spheroids or ellipsoids.
2.Projected Coordinate Systems(PCS) : The Projected Cordinate Systems are a system to represent the positions of a point in a 2d surface projected from the GCS by intersecting or tangentially wrapping the referance 3d surface.The Coordinates are represented by x and y which respectively represents the longitude and latitutde of the GCS.
3.Custom Coordinate System(CCS) : Some coordinate systems are developed to represent point in some customary manner.Such systems are included in Custom Coordinate Systems category.
The latitudes in Geographic Coordinate Systems can be represented by three different manner based on the reference surface utilized to represent the real surface of earth.,
1.Geographic or Geodetic : The angle between the point on the reference surface(spheroid or ellipsoid respectively) and equatorial plane.A point in this system is defined by (f,l,h) where f and l is the latitutde and longitude angle respectively whereas h is the vertical distance of the point above the surface of the ellipsoid.
2.Astronomical : The angle between the perpendicular from the point located on the Geoid or the real earth surface and the equatorial plane.
3.Geocentric : the angle between the equatorial plane and a normal line drawn from the center point of the ellipsoid(representing the earth surface).A point in this system is defined by (x,y,z) where all the three axis is perpendicular to each other.
Note : Both Geocentric and Geodetic latitude refers to the reference surface rather than the Earth surface.The Degree,Minute ansd Seconds or Decimal Degrees are generally utilized to represent coordinates of a point in Geographic latitutdes.
In case of PCS the coordinate of points are often found to become negative within the area of interest due to scale problems.Such negativity can be removed by applying some rectification measures and the new and modified coordinate with out the negative signs can be determined.The rectified longitudes of the point are then known as False Easting and the latitudes of the same is called as False Northing.The origin of the new coordinates after rectification is known as False Origin.
The grid on a map is defined as the lines having constant 2d cartesian coordinates (x,y). It's nearly always a rectangular system and is employed on large and medium scale maps to enable careful calculations and positioning. The map grid is sometimes not shown on tiny scale maps (about one to 1,000,000 or smaller).
The graticule on a map represents the projected position of the geographic coordinates (f,l) at constant intervals, or in alternative words graticules are the projected position of selected meridians and parallels in the 3d scale. The shape of the graticule depends mostly on the characteristics of the projection used and the scale of the map.More precisely the grids in 2d surface are the graticules in the 3d surface.
The coordinate systems can be represented in Cartesian,Polar and Spherical Coordinates.
All the coordinate systems are inter-changeble i.e.,Cartesian can be converted to Polar and vice-versa.
The Projected Coordinate Systems can be further subdivided based on :
Class (cylindrical, conical or azimuthal):
Based on the shape of the wrapped surface : The reference surface of earth, projected on a 2d plane wrapped around the globe as a cylinder will yield cylindrical map projections,when earth surface is projected on a 2d plane wrapped around it as Conical it produces Conical Projections and if the 2d surface is projected directly on the earth surface it yields Azimuthal Projections.
Point of secancy (tangent or secant):
Based on the position of the wrapped surface : If the 2d plane is wrapped around the earth surface tangentially then the projected coordinate system becomes tangential and if the former intersects the earth surface then we produce secant projected coordinate systems.The first and second point of intersections are represented by first and second standard parallels which is positioned after 1/6th distance after the initial boundary and 1/6th distance before the final boundary between the two limits of overlapped portions.
Aspect (normal, transverse or oblique):
The projected coordinate systems can also be classified based on the direction of the projected surface and the axis of earth surface.If the direction is perpendicular then it is referred under the transverse class and if it is parallel then it is grouped under normal.All other non-parallel and non-perpendicular cases are grouped under the Oblique class.The direction of the projected surface is the aspect of the projected coordinate system.
Note : Polar and Equatorial aspects are also found in case of projected coordinate systems where the projected surface is tangential or secant in the polar and Equatorial regions of the Earth surface.
Distortion property (equivalent, equidistant or conformal):
When a map is projected onto another surface, properties of the curved surface may get distorted in the projected surface.
If the angle between the lines in the original and projected surface is not distorted then such projected coordinate systems can be grouped into Conformal where as if the distance between the lines in the original and projected surface is identical then such projection coordinate systems can be classified into Equidistant and if the areas in the p-rojected map are identical to the areas on the curved reference surface (taking into account the map scale), which means that areas are represented correctly on the map then all such coordinate systems can be included in the group of equi-valent or equal area projected coordinate systems.
1.Geographic Coordinate System(GCS) : In this type of systems Latitutde and Longitude are used to represent the position of a point in a 3D surface.The surface (like sphere or spheroid or ellipsoid) which mimics the real shape of the World(referred as Geoid) is also known as Reference Surface.The real surface of the earth is very hard to predict due to its undulations and thus represented by a form of common shapes like spheroids or ellipsoids.
2.Projected Coordinate Systems(PCS) : The Projected Cordinate Systems are a system to represent the positions of a point in a 2d surface projected from the GCS by intersecting or tangentially wrapping the referance 3d surface.The Coordinates are represented by x and y which respectively represents the longitude and latitutde of the GCS.
3.Custom Coordinate System(CCS) : Some coordinate systems are developed to represent point in some customary manner.Such systems are included in Custom Coordinate Systems category.
The latitudes in Geographic Coordinate Systems can be represented by three different manner based on the reference surface utilized to represent the real surface of earth.,
1.Geographic or Geodetic : The angle between the point on the reference surface(spheroid or ellipsoid respectively) and equatorial plane.A point in this system is defined by (f,l,h) where f and l is the latitutde and longitude angle respectively whereas h is the vertical distance of the point above the surface of the ellipsoid.
2.Astronomical : The angle between the perpendicular from the point located on the Geoid or the real earth surface and the equatorial plane.
3.Geocentric : the angle between the equatorial plane and a normal line drawn from the center point of the ellipsoid(representing the earth surface).A point in this system is defined by (x,y,z) where all the three axis is perpendicular to each other.
Note : Both Geocentric and Geodetic latitude refers to the reference surface rather than the Earth surface.The Degree,Minute ansd Seconds or Decimal Degrees are generally utilized to represent coordinates of a point in Geographic latitutdes.
In case of PCS the coordinate of points are often found to become negative within the area of interest due to scale problems.Such negativity can be removed by applying some rectification measures and the new and modified coordinate with out the negative signs can be determined.The rectified longitudes of the point are then known as False Easting and the latitudes of the same is called as False Northing.The origin of the new coordinates after rectification is known as False Origin.
The grid on a map is defined as the lines having constant 2d cartesian coordinates (x,y). It's nearly always a rectangular system and is employed on large and medium scale maps to enable careful calculations and positioning. The map grid is sometimes not shown on tiny scale maps (about one to 1,000,000 or smaller).
The graticule on a map represents the projected position of the geographic coordinates (f,l) at constant intervals, or in alternative words graticules are the projected position of selected meridians and parallels in the 3d scale. The shape of the graticule depends mostly on the characteristics of the projection used and the scale of the map.More precisely the grids in 2d surface are the graticules in the 3d surface.
The coordinate systems can be represented in Cartesian,Polar and Spherical Coordinates.
All the coordinate systems are inter-changeble i.e.,Cartesian can be converted to Polar and vice-versa.
The Projected Coordinate Systems can be further subdivided based on :
Class (cylindrical, conical or azimuthal):
Based on the shape of the wrapped surface : The reference surface of earth, projected on a 2d plane wrapped around the globe as a cylinder will yield cylindrical map projections,when earth surface is projected on a 2d plane wrapped around it as Conical it produces Conical Projections and if the 2d surface is projected directly on the earth surface it yields Azimuthal Projections.
Point of secancy (tangent or secant):
Based on the position of the wrapped surface : If the 2d plane is wrapped around the earth surface tangentially then the projected coordinate system becomes tangential and if the former intersects the earth surface then we produce secant projected coordinate systems.The first and second point of intersections are represented by first and second standard parallels which is positioned after 1/6th distance after the initial boundary and 1/6th distance before the final boundary between the two limits of overlapped portions.
Aspect (normal, transverse or oblique):
The projected coordinate systems can also be classified based on the direction of the projected surface and the axis of earth surface.If the direction is perpendicular then it is referred under the transverse class and if it is parallel then it is grouped under normal.All other non-parallel and non-perpendicular cases are grouped under the Oblique class.The direction of the projected surface is the aspect of the projected coordinate system.
Note : Polar and Equatorial aspects are also found in case of projected coordinate systems where the projected surface is tangential or secant in the polar and Equatorial regions of the Earth surface.
Distortion property (equivalent, equidistant or conformal):
When a map is projected onto another surface, properties of the curved surface may get distorted in the projected surface.
If the angle between the lines in the original and projected surface is not distorted then such projected coordinate systems can be grouped into Conformal where as if the distance between the lines in the original and projected surface is identical then such projection coordinate systems can be classified into Equidistant and if the areas in the p-rojected map are identical to the areas on the curved reference surface (taking into account the map scale), which means that areas are represented correctly on the map then all such coordinate systems can be included in the group of equi-valent or equal area projected coordinate systems.
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