A few months before, I was reading an article on how the Uber and Lyft drivers were finding it hard to navigate in United States with the help of the GPS systems on their mobile devices and so in order to solve their problem, an AI research group came out with the idea of providing heat generators on the steering wheels and these generators are connected to the GPS system.Depending on the directions generated by the navigation systems, the AI software and the associated hardware generate slight warmth on the corresponding side of the steering wheel. Hence the drivers can easily take the correct left and right turns at the junctions. This news reminded me of how I used to navigate more than a decade before in Britain.
Traffic in Britain (I am not mentioning London here, but elsewhere) is not as bad as the few cities in United States because British people give more importance to their driving than generating enormous wealth, as they understand the value of life and what damage it can cause if a driver makes a major error while driving on the road. Also British drive on the left hand side of the road and since the roads are too narrow in most of the cities, (as they were built in Victorian times), the cars are all shift gears and the acceleration in smaller roads cannot be achieved as fast as it happens in United States of America, where most of the cars driven are auto-geared( ‘Shift- geared’ as they are colloquially known) . Hence less chances for speeding in small roads, which made it easier to drive in Britain.
As much as I liked driving in Britain, I hated navigating, once again because of their narrow almost invisible roads. So if I have to navigate to a new place, I will print out a google map (as GPS in cars were too expensive) and tape it to the steering wheel as I need both hands (one to steer and the other to change gears) and drive following the instructions on the map. Mostly I will arrive at the destination, at the given ETA, though a few times, I have taken a few wrong turns and ended up lost. Nevertheless, I think myself, as lucky, because I had GPS map. I don’t have to stop at the convenience stores and ask the cashier for directions as my previous generations used to do it. Like me, many are thankful about what comfort the recent navigation systems are bringing into our life.
GPS (Global Positioning system) , as many of us have known and used, is a satellite system used to determine the correct longitudes and latitudes of a given location using the receivers installed in the ground computing systems. It’s an extremely useful system for civilians, but the many facts of GPS and it’s varied applications still remain unknown to many academics and professionals alike. GPS, when invented, was not intended for civilian use at all. It was meant for military purposes to enable reconnaissance and to determine the target locations.
GPS is a brain child of Department of Defense (DoD) and MIT. It’s technical name is NAVSTAR ( NAVigation System with Timing And Ranging) . GPS has its origin to Sputnik era, where the Russian ‘Artificial Star’, as it was referred to by the US researchers of MIT, was sending sound waves at a higher frequency when it was near to them and sending lower frequency sound waves, when it went away and thus gave an idea for the locational identification of objects, based on Doppler effect. In 1963, US had sent 6 satellites orbiting the earth and they used Doppler effect to locate the submarines with respect to the location of these orbiting satellites. This was named TRANSIT and TRANSIT1B. In 1964, Dr. Ivan Getting of Raytheon Corporation, a MIT graduate in Astrophysics and a Rhodes Scholar from Oxford, developed the MOSAIC (Mobile System for Accurate ICBM Control) for US Air Force, the first ever three dimensional position defining system, based on time difference calculated based on the receipt of the radio signals. The longer the time taken, the farther the object and vice versa. This was developed for an ICBM which was supposed to achieve its mobility by travelling on railroad. This concept truly laid the foundation for the current day GPS.
The present day GPS, as introduced for commercial use in late 90s, is a multiuse space based radio navigation system owned by US government and operated by US Air Force. It provides two types of services: 1) Standard Position Services (SPS) based on coarse code acquisition (C/A) on L1 Frequency and available for all non-defense purposes like civil, commercial and scientific research, free of charge. 2) Precision Position Services based on P(Y) code for both L1 and L2 frequencies, covering the full spectrum.Access to the PPS[UC1]is restricted to US Armed Forces, US Federal agencies and selected allied armed forces and governments.
GPS, as in its present state, consists of three segments,
1)Space Segment 2) Control Segment 3) User Segment.
- The space segment is a combination of 24 satellites orbiting above the earth. These satellites are grouped into four to make six groups. Each of the groups travel on a different orbital track, covering different parts of the earth as they travel around.
- The control segment is situated on the ground and is further divided into three parts-Monitoring stations, Main Control station and Receiver Antenna.
1.Monitoring stations are responsible for tracking the satellites when they pass above them, collecting the navigational signals and feeding the observations to the main control stations
2.Main[UC2]control stations are responsible for satellite maintenance and anomaly resolutions, monitors satellite broadcasts and system integrity , provides control commands to the GPS, maintain the satellite clocks for receiving time stamped data and generates navigational messages that has to be uploaded to the GPS. These main control systems are completely backed up by a standby main control station in case of any emergencies.
3.Ground receiver antennas consists of four dedicated GPS ground antennas plus seven Air Force Satellite Control Network (AFSCN) remote tracking stations. They communicate via S-band and perform S-band ranging to provide anomaly resolution, collect telemetry data about the satellites, send commands and processor program loads to the satellites.
- The user segment consists of GPS receiver equipment which collects the data transmitted by the transmitters in the satellites and are used to beam the location information to any GPS receiver on earth as real time data, however there is a time delay between the signals to travel from the satellites to the surface of the earth and it is nearly 2 to 3 ms.The location is given as an intersection point of three spheres whose radius is equal to the distance (D1, D2 and D3) between the GPS receiver on a mobile phone or a Sat- Nav and the satellites. (a trilateration[UC3]method shown in the image in 2-dimensions). Theoretically, three measurements are enough to locate a distance, however a fourth satellite is also used to improve accuracy in military satellites and the resultant is the location within a few inches or a perfect longitude and latitude co-ordinates.
Though the Global Positioning System, with 24 satellites, was first introduced by United States of America, as a fully public owned venture, for both military and civilian use, many countries followed its suit and has successfully operating their own Sat- Nav systems in the last decade or so. The other GPS technologies available for use are 1) Galileo System in European Union also known as Global Navigation Satellite System (GNSS), consisting of 30 satellites. The research, development, deployment and successful operations is carried out as a combined effort of both private and public sectors.
2) GLONASS (Russian Global Navigation Satellite System) owned by Russia, originally developed by USSR operates, similar to US GPS with 24 satellites, however unlike US GPS, GLONASS operates at the same frequency and code for both military and civilian purposes.
3) Quazi – Zenith Satellite System (QZSS), developed by Japan. It became fully operational in 2013, consists of only 3 satellites covering the areas around Japan and the near-by parts of Asia. This Satellite system operates in addition to US GPS and strengthens the accuracy rate of United States GPS.
4) Beidou Navigation Satellite System (BDS) is owned by China. Originally started in 2000, with only 3 satellites covering the nation, China has increased its capacity to 30 satellites in 2018, with its 3 recent launches providing global coverage.
5) INRSS (Indian National Regional Satellite System) called NavIC is the recent of all the six, with only 7 satellites to cover the area around Indian ocean, both land and sea, which became operational in 2017. Recently after many countries experimenting GPS as a joint private and public sector venture, US Air Force has finally given up the GPS monopoly and Boeing is currently engaged in developing a new 12 satellite system, which has a higher accuracy and longer life expectancy.
I think I have given enough information on GPS and so I will move on with GIS and how it differs from GPS.
GIS can be considered as one of the many applications of GPS, which are 1) Locating( providing correct longitudes and latitudes of the geographical location)2) Navigating (Moving from one location to another location) 3) Tracking ( Following the movement of a shipment or a vehicle from departure to arrival )4) Mapping or surveying ( To visually represent the geographical data in a manner, easy to interpret, question and understand) 5) Timing (to provide 3D real time representation of any geo-position on earth, providing the 4th dimension) .The main difference between GPS and GIS being, GIS stores and uses the data collected by the GPS .
Geographical Information Systems (GIS) are used to store, analyze, monitor and control large amounts of GPS data retrieved using Geo-positional satellites. This data is then visually represented in the form of geographical maps used in mapping and surveying purposes. GIS consists of five major components. They are
·Hardware (computing systems, Networks (LAN and WAN) and Peripherals) ,
·Software (GIS software, OS software, Database software, Network Software)
·People (Analysts, Image , App experts, Engineers, Managers, End users and customers)
·Data ( Vector[UC4]data, Image[UC5]or Raster data)
·Compliance methodologies (Standards, Procedures, guidelines and specifications).
GIS is a database which is split into number of data layers which can be represented visually as maps, reports or charts. The GIS software can be used to obtain some of the following layered maps such as geo-spatial topographical maps, digital elevation models, aerial photography, critical infrastructure maps, agricultural survey maps and census maps. A good example can be the aerial maps of Hawaii Kilauea eruption a few months before. The eruption was captured by several satellites which orbited around the area at the specific time. These images are fed to the GIS software, which converted them into several layered maps of the area. These layered maps helped the civic authorities of Big Island in providing recovery, response, mitigation efforts to the people living in those areas, such as Leilani estates. Also it helps them to improve their preparedness in case of another eruption in the future.
ght © 2018by Uma Chandrasekhar. All rights reserved.
The above GIF shows the GIS depiction of the Steelhead haven area in Oso, Washington State, where a mud Slide cleared off many buildings and woodlands. The GIF depiction helped the authorities in the rescue operation and the rebuilding of the neighborhoods in the area of Oso.
The inputs to the GIS software are generally the location of the area in latitudes and longitudes, the aerial environment characteristics like wind velocity, wind direction and humidity, mist in the air, temperature and the local weather conditions. Once the inputs are supplied then queries can be provided to the database to retrieve the correct information to prepare the layered visual maps and then this data is fed to the GIS computing software to create the various maps and charts enabling the authorities to identify and quarantine the affected area. If the database used is extensive and comprehensive, then it is possible to find the number of causalities due to the calamity as quickly as possible. This is extremely useful for first responders to provide rescue and sheltering options and also to the families of the affected areas, the relief of safety or closure.
The above web link shows the different layers of the GIS software, of Pittsburgh region in USA.
Many different types of data can be integrated and represented as a map layer. From a simple base map, it is possible to obtain, by mixing different data, a number of layers like
- 3D imagery (Elevated imagery of the area covered, in other words, seeing from the top),
- Demographics (Street, cities, Districts etc., ),
- Topography ( Mountains, trees and rivers )
- Wetlands ( Only swamps and marshy lands ) ,
- Zoning ( portioning a part of the land for the benefit of the owner legally, for example, flood risk or other catastrophe risk areas can be taken away from the owner by the city council or county council ,based on zoning laws , after compensating the owner for the same),
- Parcels (A smaller sized zoning).
A special benefit of this type of data layering is when these layers are superimposed or arranged on top of each other, it helps to find undetected spatial trends and relationships and thus results in spotting the undermined characteristics of a given location.
The architecture of GIS can be either single user, multi user or shared.
1.In a single user environment, the database is primarily used for a single project used by a single entity, such as an imagery, captured by a commercial drone, used to understand the location for a single-specific purpose.
2.In a multi user environment, a centralized database is used by multiple users working on different projects,. To cite an example, a database of a city or a civic authority used by many of its residents for varied purposes.
3.In a shared architecture, a distributed database is used by many users in a network. One possible example, I can think of, for this, can be the shared data from different autonomous vehicles passing through the same area, stored in different cloud environments like Microsoft Azure, Google Cloud, AWS etc.,
GIS is an advanced field of work which brings many other fields like Information Technology, Spatial analysis, Quality Assurance and quality control of data, cartography and remote sensing along with business strategies.
- Information technology is used to ensure uninterrupted internet connectivity or connection through satellites. This helps in acquiring the images and videos required for the analysis and visualization. Also it helps in usage of the information from a database stored in a centralized server.
- Spatial analysis is the analysis of spatial data in order to interpret and understand it. Spatial data can be used to deduce a location based on its geometric properties. If we consider, a triangle, a spatial analysis gives information like the length of the triangle, the three angles which makes the triangle, the median point which happens to be the center of the triangle etc.,The same can be said for any geometric polygon. Non- spatial data gives details about non-locational information. This is sometimes referred as attribute data. This information describes the properties of a person or thing. Examples of attribute data can be mass of an element in a periodic table. The mass of the element remains the same irrespective of its location, whether on earth or on moon, uninfluenced by any other force including gravitational force. Spatial analysis helps in isolating the spatial data from the non- spatial data and thus helps the GIS software to interpret the same.
- Maintaining the quality of the data is the most important aspect of any database software, because the data analytics is as good as the quality of data, hence the data hygiene is highly important. The main problems which prevents the data quality are incomplete data, missing records, outdated records and duplicate data. The importance to maintain the relevance, adequacy and originality of the data is more important in providing a quality elucidation of the data and its representation into visual form.
- Cartography[UC6]is the art of map making.
- GIS plays an important role in business strategies and decision making processes. It helps in gaining revenue by enabling focus on locational details of the customers and thus increasing customer numbers. It also helps in reducing OPEX and CAPEX by combining different store and warehouse locations and employing local vendors and people. The maximum impact of GIS strategy is achieved in five simple steps :1) Find the right strategy 2) Assess and plan the requirements as per the chosen strategy 3) Fit the orders and clients to the initial capabilities and resources 4) If the needs exceed the existing requirements, expand and diversify 5) Finally, once expanded, check everything in place by checking the strategy against current resources and requirements.
The many applications of Spatial analytics and GIS are in the field of healthcare, retail, consumer, media and commercial real estate. The varied civil engineering applications which we saw above is summarized below as follows: 1) Transportation 2) Environment Impact Assessment 3) Remote Sensing 4) Urban development 5) Landfill site selection 6) Mineral mapping 7) Mine detection 8) Pollution Monitoring 9) Chemical and other Hazard assessment 10) Resource Management 11) Watershed Analysis ( Hydrology – finding the water sources and linking them to databases helps in finding the landscape design process) 12) Flood Modelling
The future of GPS and GIS is evolving and bright. In order to achieve success in the field of GIS, it’s important to have the right approach, winning strategy and efficient implementation. Just as in any other new technology, the mindset of the people plays an important role in bringing significance to the field of GIS. The humans are the essence of GIS, whether it is the executive management or the technical leadership or the support staff, the vision and the value lies with them. Yet another important thing to remember in adopting a new technology is versatility and agility. These two mindsets will help to bring any product or configuration to its best.
[UC1]Ack : www.nasa.gov/ GPS_history
[UC3]This is different from triangulation techniques which are used to determine the locations of radio transmitters, using one radial distance and two angles. Trilateration uses three distances only and not angular measurements. To explain in detail let’s consider three satellites S1, S2 and S3 and their positions known. When one satellite signal from S1 beams and hits the GPS receiver, then we know the distance between the receiver and the satellite and not the angle which the signal made with the receiver. In other words, a circle C1 is formed with the distance as its radius. So the location can be anywhere on the circumference of the circle. The same happens when the second GPS signal from satellite S2 is broadcast. The distance between the receiver and the satellite is calculated using the time taken to travel from the space to the surface and this distance becomes the radial distance to form another circle C2. But with just two signals the location can be anywhere the two circles intersect. So we use a third satellite signal form S3, and using the distance between the satellite and the receiver, we form the third circle and the precise location is intersection of the three circles.
[UC4]Represented as color-connated polygons represented as direction and magnitude
[UC5]Represented by matrix of pixels, with discrete numerical values for color.
[UC6]This is a different field and one of the most important parts of the GIS software and you may finda full article on this subject , possibly , in the coming months.
