Geographical or Geospatial Information Systems (GIS) is a great way to represent data in a mapped format and analyze that data in a database environment. By providing a spatial analysis of suitably coded data, it is possible to provide striking, visual representations of data. These representations can often reveal patterns and trends that might otherwise have gone unnoticed without the use of GIS techniques (Nofal, 2012). GIS is defined as technological systems and databases that allow the recording of where, what, and when in a visual geographic or mapping format.
GI systems were originally conceived as something separate from the world they represent – a special kind of information system, often located on a user’s desk, dedicated to performing special kinds of operations related to location. However, today such information pervades the Internet. This abundant of information can be accessed by our smartphones and other personal devices, and is fundamental to the services provided by governments, corporations, and even individuals. Overall this digital world has become one vast, interconnected GI system (Longley, Goodchild, Maguire, & Rhind, 2015).
When thinking about geographical information, most people still correlate it with physical or paper maps. This type of information stays the same and can only be visually analyzed or up for interpretation depending. GI databases, on the other hand, can constantly be updated and analyzed with different tools. This no longer allows for interpretation depending but makes it clear with the input of notes and details. The advantages of this digital representation outweigh those previously. The similarities between the two obviously allow the sharing of information to a wider group. The printing of information has been used for centuries now in allowing information to be distributed and known by many, but with the internet, digital information has given access to this information to anyone and almost everyone.
Building on this information can be done in many different ways, and us as humans can assemble far more knowledge about our planet than we ever could individually (Longley, Goodchild, Maguire, & Rhind, 2015). Building representations can be done around different purposes and are reinforced by rules and laws created by humans. There are three principles of building representations around geographic samples:
Proximity effects are key to representing and understanding spatial variations and to joining incomplete representations of unique places.
Issues of geographic scale and level of detail are key to building appropriate representations of the world.
Different measures of the world very in correlation with another related variable, and understanding the nature of these correlations that very can help us to predict.
These three principles help us better represent spatial and temporal phenomena in the observable world, and because the observable world is complicated, this task is difficult, prone, and uncertain (Longley, Goodchild, Maguire, & Rhind, 2015).
Principles of GPS
The first satellite sends a signal to the next receiver at the ground which receives the signal at another time later. The time arrival of the GPS signals from various satellites are measured simultaneously. The GPS signal is then decoded and the signal propagation time is established and multiplied by the pseudo ranges. This is followed by decoding the navigation message and converting it into satellite positions. At least four pseudo ranges obtained from the four satellites at the same time are used to calculate the position in the ECEP frame. The ECEF position is then converted to latitude-longitude-height in a geodetic system (Ashby, 2003).
Applications of GPS
GPS is an element of infrastructure source for the whole world. This element is open, free and dependable and this has allowed the development of applications associated with it. There are several applications associated with the GPS system. Such technology has been installed in cell phones, shipping containers, bulldozers, and ATMs ("GPS.gov: Applications", 2016)
GPS enables the growth of productivity in the different areas of the economy to include farming, mining, surveying, construction, package deliveries, and the logistic supply chain management. Many sectors use the communications systems that are developed through the GPS systems for its synchronization. The most common sensitive areas that uses this technology include banks systems, power grids, the financial market for better synchronization of time and information. Some of the modern wireless networks that established with some applications do not operate without GPS ("GPS.gov: Applications", 2016)
GPS systems have applications in the security sector too. The nation’s security system is integrated with the GPS system to facilitate the military operations to help in mitigation insecurity in a country. In the United States for instance, nearly all the military assets from cars to ammunitions are equipped with the GPS as they are delivered by the supplier.
Again the GPS systems have application in the health and safety sectors. The GPS system can help in preventing the occurrence of accidents, assisting in the searching and rescuing efforts. During emergencies, the GPS will help in locating the emergency services that are needed at that moment. The NextGen –Next Generation air transportation system uses GPS systems to enhance the safety of the flights while increasing the capacity of the airspace. The department of environmental science also uses GSP to enable them to carry out their activities smoothly. The activities carried out here include; earthquake monitoring, weather forecasting and environmental monitoring ("GPS.gov: Applications", 2016)
Requirements for an effective system of georeferencing
For a georeferenced system to be effective, it must have good parameters. Firstly, the georeference must be unique to ensure that there is no other location that is associated with reference used. In this case, there will be no confusion, about the referenced position or location (Google, 2016)
Secondly, the meaning of any georeferencing information must be shared among all the people who wish to use the information to ensure consistency in any new system that is being created. This will prevent the data overlapping and unnecessary repetitions. The information of the geographic systems must also be shared. The idea of uniqueness and the shared meaning will allow people to relate to different kinds of information that are associated with a common location (Google, 2016)
Thirdly, a georeference should be persistent through time. The frequent changing of the georeference will create a lot of confusion and the updating of the associated information will be very expensive. A problem will result when the georeference serve more than one function or is used by different companies or individuals for a variety of priorities. For instance, a challenge arises when the municipality adds more land to their system, and this will create a problem for the mapping agencies and for researchers studying that municipality over time. Lastly, every georeference should have an associated spatial resolution that should be equal to the size of the area that is assigned to the georeference. In analogy, the address of the mails should have a spatial resolution that is equivalent to the size of the mailbox or the area of the parcel of structure or the land that is assigned to that address. However, many georeferencing systems are unique in some are or domain the surface of the earth (Google, 2016)
References
Ashby, N. (2003). Relativity in the Global Positioning System. Living Reviews in Relativity, 6. http://dx.doi.org/10.12942/lrr-2003-1
Google, (2016). Retrieved 24 April 2016, from Ashby, N. (2003). Relativity in the Global Positioning System. Living Reviews in Relativity, 6. http://dx.doi.org/10.12942/lrr-2003-1
GPS.gov: Applications. (2016). Gps.gov. Retrieved 24 April 2016, from http://www.gps.gov/applications/
