2. INTRODUCTION :
• Most data management professionals are more
experienced with classical tabular data in Cartesian (rows
and columns) structures
as found in most business,
govrnmentent and scientific
databases.
3. GEOSPATIAL DATA :
• Geospatial data has significantly different structure and Function
includes structured data about objects in the spatial universe –
their identity, location, shape and orientation and other things
we may know about them.
4. • Geographical data describe an incredibly wide range of objects
or business assets – roads, buildings, property lines, terrain,
infrastructure, hydrology and ecosystems.
• All these objects can be described in terms of points, lines and
polygons – and tables of these objects constitute the tabular
portion of geospatial data.
5. GEOGRAPHICAL INFORMATION
SYSTEM (GIS)
• Geographical information system (GIS) technology also
accommodates some kinds of unstructured data (usually raster
imagery) that can be tagged and geocoded (given precise
positional characteristics) and integrated by GIS software to the
other kinds of map data.
6. • The management of GIS data and metadata is somewhat
different. Whereas traditional tabular data could be understood
by a human looking at any printed expression of the data
(usually in rows and columns, even on paper), raw GIS data is
generally meaningless to the human eye until converted into a
map.
7. IMPORTANCE OF GIS :
1. Perform Geographic Queries and Analysis
2. Improve Organizational Integration
3. Make Better Decisions
4. Making Maps
8. VECTOR AND RASTER MODELS :
• Geographic information systems work with two fundamentally
different types of geographic models – the “vector” model and
the “raster” model.
9. VECTOR DATA MODEL :
• In the vector model, information about points, lines and
polygons is encoded and stored as a collection of x, y
coordinates.
• The location of a point feature, such as a bore-hole, can be
described by a single x, y coordinate.
• Linear features, such as roads and rivers, can be stored as a
collection of point coordinates. Polygonal features, such as sales
territories and river catchments, can be stored as a closed loop
of coordinates.
10. RASTER DATA MODEL :
• The vector model is extremely useful for describing discrete
features, but less useful for describing continuously varying
features such as soil type or accessibility costs for hospitals.
• The raster model has evolved to model such continuous
features. A raster image comprises a collection of grid cells
rather like a scanned map or picture.
• The vector model is extremely useful for describing discrete
features, but less useful for describing continuously varying
features such as soil type or accessibility costs for hospitals.
11.
12.
13. COMPONENTS OF A GIS :
• A working GIS integrates five key component:
1. hardware
2. Software
3. Data
4. People
5. Method
14. 1. HARDWARE :
• It is the computer on which a GIS operates. Today, GIS software runs
on a wide range of hardware types, from centralized computer
servers to desktop computers used in stand-alone or networked
configurations.
2. SOFTWARE
• The GIS software provides the functions and tools needed to store,
analyze and display geographic information. Key software
components are:
15. 1. Tools for the input and manipulation of geographic
information.
2. A database management system (DBMS).
3. Tools that support geographic query, analysis and visualisation.
4. A graphical user interface (GUI) for easy access to tools.
16. 3.DATA :
• Possibly, the most important component of a GIS is the data.
Geographic data and related tabular data can be collected in-
house or purchased from a commercial data provider.
• A GIS will integrate spatial data with other data resources and
can even use a DBMS, used by most organizations to organize
and maintain their data, to manage spatial data.
17. 4.PEOPLE :
• The GIS technology is of limited value without the people who manage the system
and develop plans for applying it to real-world problems.
• The GIS users range from technical specialists who design and maintain the
system to those who use it to help them perform their everyday work.
5.METHOD :
• A successful GIS operates according to a well-designed plan and
business rules, which are the models and operating practices
unique to each organization.
18. CHAPTER – 5
GLOBAL POSITIONING SYSTEM
(GPS)
INTRODUCTION :
• Global positioning system (GPS) is a satellite-based navigation system, consisting
more than 20 satellites and several supporting round facilities.
• Global Positioning System (GPS) has tremendous potential for better transport
management/planning. Traffic management, emergency services (fire service,
accident relief, ambulance service, policing, etc.), are the few areas where GPS can
play significant role due to its capability to provide near accurate location (latitude
longitude, altitude) and other details.
19. Concept of GPS :
• GPS consists of a constellation of radio navigation satellite
and a ground control segment.
• It manages satellite operation and users with specialized
receivers who use the satellite data to satisfy a broad range of
positioning requirements.
20. KEY FEATURES OF GPS:
• GPS receiver measures distance using the travel time of radio
signals.
• To measure travel time GPS needs very accurate timing that is
achieved with some techniques.
• Finally one must correct for any delays, the signal experience as
it travels through the atmosphere.
22. 1.GPS GROUND CONTROL
STATIONS
• The ground control component includes the master control
station at Falcon Air Force Base, Colorado Springs, Colorado and
monitor stations at Falcon AFB, Hawaii, Ascension Island in the
Atlantic, Diego Garcia in the Indian Ocean an Kwajaleinn Island
in the South Pacific.
• The control segment uses measurements collected by the
monitor stations to predict the behavior of each satellite’s orbit
and atomic clocks.
23. 2. GPS SATELLITES
• Prediction data is linked up to the satellites for transmission to
users. The control segment also ensures that GPS satellite orbits
remain within limits and that the satellites do not drift too far
from nominal orbits.
• The space segment includes the satellites and the delta
rockets that launch the satellites from Cape Canaveral in
Florida, United States. GPS satellites orbit in circular orbits at
17,440 km altitude, each orbit lasting 12 hours.
24. • The orbits are tilted to the equator by 55 A° to ensure coverage
in Polar Regions. The satellites are powered by solar cells to
continually orientate themselves to point the solar panels
towards the sun and the antennas towards the earth.
25. 3. GPS RECEIVERS
• When you buy a GPS, you are actually buying only GPS receiver
and get free use of the other two main components, worth
billions of dollars – compliments of the Government of the
United States.
• The ground stations send control signals to the GPS satellites.
The GPS satellites transmit radio signals and the GPS receivers,
receive these signals and use it to calculate its position.
26. GPS FUNCTIONS:
1. Giving a location
2. Point-to-point navigation
3. Plot navigation
4. Keeping track of your track:
27. 1. GIVING A LOCATION:
• This is the whole point of a navigation system: its ability to
accurately triangulate your position based on the data
transmissions from multiple satellites.
It will give your location in coordinates, either latitude and
longitude or Universal Transverse Mercators (UTMs). Developed
by the military, UTMs are used to pinpoint a location on a map.
Most topographical maps have UTM gridlines printed on them.
28. 2. POINT-TO-POINT NAVIGATION:
• This GPS navigation feature allows you to add waypoints to your
trips.
• By using a map, the coordinates of a trailhead or road or the
point where you are standing, you can create a point-to-point
route to the place where you are headed.
• You will have trip mapped out, including any stops you add in.
29. 3. PLOT NAVIGATION:
• This feature in a global positioning system allows you combine
multiple waypoints and move point-to-point.
• Once you reach the first waypoint, the GPS can automatically point
you on your way to the next one.
4. Keeping track of your track:
• Tracks are some of the most useful functions of portable navigation
systems.
• This virtual map is called a track and you can programme the GPS
system toautomatically drop track-points as you travel, either over
intervals of time or distance.
30. GPS APPLICATIONS :
A. Guidance
• Point guidance
• Swath guidance
B. Control
• Variable rate application
• Variable tillage depth
• Variable irrigation
31. C. Mapping
• Soil properties
• Chemical application
• Chemical prescriptions
• Tillage maps
• Yield mapping
• Pest mapping
• Topographic maps
• Planting map
