Local coordinates are the ones used in a local coordinate system or a local coordinate space. Simple examples:
Local systems exist for convenience. On ancient times, every work was made on relative bases as there was no conception of global systems. Practically, it is better to use local systems for small works as houses, buildings... For most of the applications, it is desired the position of one element relative to one building or location, and in a more local way, relative to one furniture or person. In a regular way, you will not give your position by geographical coordinates rather than "I am 15 meters away of the entry to the building". So it is a pretty common way to locate things.
It is possible to bring latitude and longitude for all terrestrial locations, but unless one has a highly precise GPS device or you make astronomical observations, this is impractical. It is much simple to use a tape, a rope, a chain... The position information (global) should be transformed into a location. Position refers to a numeric or symbolic description within a spatial reference system, where as location refers to information about surrounding objects and their interrelationships.[1] (Topological space)
In computer graphics and computer animation, local coordinate spaces are also useful for their ability to model independently transformable aspects of geometrical scene graphs. When modeling a car, for example, it is desirable to describe the center of each wheel with respect to the car's coordinate system, but then specify the shape of each wheel in separate local spaces centered about these points. This way, the information describing each wheel can be simply duplicated four times, and independent transformations (e.g., steering rotation) can be similarly effected. Bounding volumes of objects may be described more accurately using extents in the local coordinates, (i.e. an object oriented bounding box, contrasted with the simpler axis aligned bounding box). The trade-off for this flexibility is additional computational cost: the rendering system must access the higher-level coordinate system of the car and combine it with the space of each wheel in order to draw everything in its proper place.
Las coordenadas locales también brindan a los diseñadores digitales un medio para sortear los límites finitos de la representación numérica. Las marcas de la banda de rodadura de un neumático, por ejemplo, se pueden describir en milímetros permitiendo que todo el neumático ocupe todo el rango de precisión numérica disponible. Los aspectos más grandes del automóvil, como su bastidor, podrían describirse en centímetros, y el terreno por el que viaja el automóvil podría especificarse en metros.
En topología diferencial , las coordenadas locales de una variedad se definen mediante un atlas de cartas . La idea básica detrás de los gráficos de coordenadas es que a cada pequeña porción de una variedad se le puede dotar de un conjunto de coordenadas locales. Estos se reúnen en un atlas y se unen de tal manera que sean autoconsistentes en la variedad.
En Cartografía y Mapas , la forma tradicional de trabajar son los datos locales . Con un dato local [2], la tierra se puede mapear en áreas relativamente pequeñas como país. Con la necesidad de sistemas globales, las transformaciones entre datos se convirtieron en un problema, por lo que se crearon datos geodésicos. En el mundo se han utilizado más de 150 datos locales.