Modern receivers GPS have caught up of the costs many contents. After the cellular telephone we are assisting to the spread of a new one cult: that one of the navigator to satellitare personal. The market by now offers to solutions to low cost for all employs it and all the pockets that are not only revealed effective for navigation to satellitare in himself and himself, but also for civil uses, for the monitoring of the services you furnish and for the control of the territory. Several solutions exist:
* Integrated: they are devices portable you All-in-One that they incorporate a receiver GPS, display a LCD, a loudspeaker, the processore who executes the instructions, dates usually from an operating system owner, one slot for memory cards where memorizzare the cartography.
* Hybrid: they are devices portable you (PC, Palmari, SmartPhone) that, been born for various, rendesi scopes they are adapted to navigation to satellitare through the connection of an external receiver GPS (Bluetooth or via cable) and the adoption of a dedicated software, in a position to managing the cartography.
With the capillary spread of systems GPS, and the consequent discouragement of the costs of the receivers, many producers of cellular telephones have tried to insert a module GPS to the inside of their products, opening themselves therefore to the new market of services LBS (Location Services Base, services base to you on the positioning). Such services come more and more take advantage of in order to offer to you also on web of the services the many profits. However, the relative slowness with which GPS finishes them acquires the own position at the moment of the ignition (in average, between the 45 and 90 second ones), due to the necessity to try the satellites in sight, and consequent the remarkable engagement of energetic resources hardware and, has refrained at first this type of coupling. In the last years, but, it has been introduced in this type of telephones the system Assisted GPS, saying also "A-GPS", with which it is possible to obviate to such problems: they are made to reach finishes them GPS, through the net of mobile telephony, the information on the visible satellites from the cell to which the customer it is coupled. In this way a telephone A-GPS can in little second ones gain the own position begins them, in how much is assumed that the satellites in sight from the cell are same the visible ones from finish them under its cover radio. Such system is much profit also like emergency service, as an example in order to localize means or wounded persons later on to an incident.
Saturday, February 9, 2008
Cartography and open source
The laws on the tutelano copyright the cartographic works and second preview the payment of royalties the dispositions of their authors. Between the most complete surveys of the Italian territory the papers of Military Navy and situated of Italian Atlas (the official reference of the national cartography re-enter). The material is available free of charge for Public Administration, and to payment for the citizens.
In the United States the national cartography is not covered from copyright and that has favorite the spread of the interactive maps with services which maps.google.com and earth.google.com. The sevizio of google it is subject to payment for I use it of the paper beyond a sure level of zoom, in order to visualize enterprises or other agencies.
A free cartography has been able to extend also to areas of the territory that do not correspond to large agglomerate city or tourist zones to you, places for which little customers would use the consultation service.
In Europe, a cartography "owner" is not material usable for distributions open source that they must trace one new cartography without to use the existing material. They exist software (in particular applet java) in a position to acquiring a geographic paper in jpeg and supplying base services as interactive navigation and the calculation of the optimal distance. However, a private use therefore as a public distribution of these services is subject to the law of the copyright.
In the surveys it still lacks a standard formattazione of the cartography for which they are used you form you of vectorial diagram or forms to you raster; between those of vectorial diagram the extension jpeg on which is diffused mainly is estimated and traced the optimal distances. Less diffuse they are other you form you of vectorial diagram that concurs also to define metadati with which the customer can personalize the papers with important information for he. The software of conversion between the several one often forms to you is programs to payment.
Between the greater plans of a software open source for navigation to satellitare (alternative to the diffuse Tom Tom and others), it is from noticing that the Roadster plan concurs to define of the metadati ones regarding the GPS_Drive plan.
In the United States the national cartography is not covered from copyright and that has favorite the spread of the interactive maps with services which maps.google.com and earth.google.com. The sevizio of google it is subject to payment for I use it of the paper beyond a sure level of zoom, in order to visualize enterprises or other agencies.
A free cartography has been able to extend also to areas of the territory that do not correspond to large agglomerate city or tourist zones to you, places for which little customers would use the consultation service.
In Europe, a cartography "owner" is not material usable for distributions open source that they must trace one new cartography without to use the existing material. They exist software (in particular applet java) in a position to acquiring a geographic paper in jpeg and supplying base services as interactive navigation and the calculation of the optimal distance. However, a private use therefore as a public distribution of these services is subject to the law of the copyright.
In the surveys it still lacks a standard formattazione of the cartography for which they are used you form you of vectorial diagram or forms to you raster; between those of vectorial diagram the extension jpeg on which is diffused mainly is estimated and traced the optimal distances. Less diffuse they are other you form you of vectorial diagram that concurs also to define metadati with which the customer can personalize the papers with important information for he. The software of conversion between the several one often forms to you is programs to payment.
Between the greater plans of a software open source for navigation to satellitare (alternative to the diffuse Tom Tom and others), it is from noticing that the Roadster plan concurs to define of the metadati ones regarding the GPS_Drive plan.
Cartography
The cartography is with of scientific, technical and artistic acquaintances finalized to the symbolic but veritiera rappresentazione of geographic information - or demographic, economic, political, culturalstatistics , however in relation to the geographic place in which they are come true - on supports plans (geographic papers) or spherical (globes).
The geometric or mathematical techniques that transform the expressed points in geographic coordinates in points expressed in cartesian coordinates call cartographic projections.
The cartographic studies and the relative applications in the various fields applied to you have been rivoluzionate from the development and the spread of Sistemi Informed to you Geographic (GIS).
The first one to make a paper of the Mediterranean was Dicearco from Messina, that it devised a system based on two orthogonal main lines on which a reticulum of squares was developed.
The geometric or mathematical techniques that transform the expressed points in geographic coordinates in points expressed in cartesian coordinates call cartographic projections.
The cartographic studies and the relative applications in the various fields applied to you have been rivoluzionate from the development and the spread of Sistemi Informed to you Geographic (GIS).
The first one to make a paper of the Mediterranean was Dicearco from Messina, that it devised a system based on two orthogonal main lines on which a reticulum of squares was developed.
Changes of the celestial coordinates
Because of the movements in the long term of the Earth (first of all that one known with the precession name of the equinoxes), the stars do not have celestial coordinates of all the fixed ones but they are moved with the time. This movement is independent from the motion just of the stars, because draft of a movement of the observer rather than of the star. To eye knot and on scales of little years he is imperceptible, but for the astronomical observations the problem is placed to specify which moment one co-ordinate refers. It has been therefore invented the age concept : all the coordinates specify respect to an age, and exist algorithms in order to pass from an age to the other.
In spite of the entity of the movement it can appear paltry on short periods, on a scale of time of millenia it can carry to remarkable variations in the positions of the stars; as an example, between approximately 13000 years the celestial North Pole it will be indicated from Vega, and not more from the Polar Star.
In spite of the entity of the movement it can appear paltry on short periods, on a scale of time of millenia it can carry to remarkable variations in the positions of the stars; as an example, between approximately 13000 years the celestial North Pole it will be indicated from Vega, and not more from the Polar Star.
Galactic Coordinates
The galactic coordinates take like plane of reference that galactic one that forms an angle of 62°41 ' with the celestial Equator and like direction of origin that one of the characterized from the measures of radio astronomy and placed galactic center in the constellation of the Sagittario (?=17h 42m 30s, and?=-28°55' 18").
These references allow to define a North Pole and a galactic South Pole through slowly galactic the normal direction al and passing for the Sun. The galactic North Pole has equatorial coordinates?=12h 49m and?=+27° 24'.
A galactic longitude (l) and a galactic latitude are defined (b), both measured in degrees.
The galactic latitude is traced on the great circles passing for the poles and varies from b=-90° (galactic South Pole) to b=+90° (galactic North Pole).
The varied galactic longitude from l=0° (center of the galaxy) to l=360° and is increasing in the back of spin of the Milky Way (seen from the North Pole the longitude grows in counter-clockwise sense).
These references allow to define a North Pole and a galactic South Pole through slowly galactic the normal direction al and passing for the Sun. The galactic North Pole has equatorial coordinates?=12h 49m and?=+27° 24'.
A galactic longitude (l) and a galactic latitude are defined (b), both measured in degrees.
The galactic latitude is traced on the great circles passing for the poles and varies from b=-90° (galactic South Pole) to b=+90° (galactic North Pole).
The varied galactic longitude from l=0° (center of the galaxy) to l=360° and is increasing in the back of spin of the Milky Way (seen from the North Pole the longitude grows in counter-clockwise sense).
equatorial Coordinates
They are reported to fixed references on the celestial sphere, therefore they do not vary with the position of the observer and the diurnal motion of s. the c.
They are taken like references:
* the celestial Equator;
* the hour circles;
* the ram point (), point of the celestial Equator in which the Sun is found when spring equinox passes from the celestial hemisphere south to thatnorth ().
The declination () of a star is its angular distance from the celestial Equator (from -90°, to the South Pole, +90° to the North Pole).
The right ascension () of a star is the angular distance between the intersection with the celestial Equator of its hour circle and the point of ram, measured towards east. The right ascension can also be expressed in second hours, minuteren and, placing 1 hour = 15°.
To times, in place of the declination the polar distance is used (p), that it is the angular distance of the star from the celestial North Pole and that varies from 0° to 180°. In any case, p +? = 90°.
They are taken like references:
* the celestial Equator;
* the hour circles;
* the ram point (), point of the celestial Equator in which the Sun is found when spring equinox passes from the celestial hemisphere south to thatnorth ().
The declination () of a star is its angular distance from the celestial Equator (from -90°, to the South Pole, +90° to the North Pole).
The right ascension () of a star is the angular distance between the intersection with the celestial Equator of its hour circle and the point of ram, measured towards east. The right ascension can also be expressed in second hours, minuteren and, placing 1 hour = 15°.
To times, in place of the declination the polar distance is used (p), that it is the angular distance of the star from the celestial North Pole and that varies from 0° to 180°. In any case, p +? = 90°.
Coordinated horizontal
Calls also "altazimutali coordinates", are reported to the observer, presupposed immovable, and therefore for every star they vary continuously, and they depend on the position of the observer. They are taken like references:
* the horizon, the maximum circumference that separates the visible celestial hemisphere from that invisibile;
* the meridian, the maximum circumference passing for the Zenith of the observer and the poles, that it meets the horizon in the points North and South;
* the foot of the star, point of the horizon more close to the star.
The height (h) is the angular distance of the star from the horizon, and varies between -90° (Nadir) and +90° (Zenith).
The Azimuth (a) is the angular distance between the point North and the foot of the star, measured in hour sense, and varies between 0° and 360°.
The smaller circumferences formed from the points of equal height are the height circles or almucantarat. The maximum semi-circumferences comprising the points of a data Azimut are called vertical.
To times, in place of the height the zenith distance is used them (z), that it is the angular distance of the star from the Zenith of the observer and that varies from 0° to 180°. In any case, z + h = 90°.
* the horizon, the maximum circumference that separates the visible celestial hemisphere from that invisibile;
* the meridian, the maximum circumference passing for the Zenith of the observer and the poles, that it meets the horizon in the points North and South;
* the foot of the star, point of the horizon more close to the star.
The height (h) is the angular distance of the star from the horizon, and varies between -90° (Nadir) and +90° (Zenith).
The Azimuth (a) is the angular distance between the point North and the foot of the star, measured in hour sense, and varies between 0° and 360°.
The smaller circumferences formed from the points of equal height are the height circles or almucantarat. The maximum semi-circumferences comprising the points of a data Azimut are called vertical.
To times, in place of the height the zenith distance is used them (z), that it is the angular distance of the star from the Zenith of the observer and that varies from 0° to 180°. In any case, z + h = 90°.
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