GLOBAL POSITIONING SYSTEM
UNIT 3: ASSIGNMENT
SUBMITTED BY: KHUSBOO
TO
MISS SANJANA
1.WHAT IS GEODESY?
Geodesy is the science of measuring and representing the geometry, gravity and
spatial orientation of the earth in temporally varying 3D.It is called planetary
geodesy when studying other astronomical bodies, such as planets or
circumplanetary systems.
2. EXPLAIN THE SHAPE OF EARTH. DEFINE
GEOID/ DATUM/ ELLIPSOID.
In 17th century, Issac Newton deduced from theoretical considerations that the
earth was slightly flattened at the poles and bulged slightly at the equator, due to
earth’s rotation on its axis that is why it is called GEOID.
Ellipsoid: reference surface for horizontal position.
Geoid: reference surface for elevation.
Datum: it is referred as geodetic datum or a reference point of the earth surface
which is generally coincides with mean sea level.
3. WHAT IS COORDINATE SYSTEM/ WHAT IS
ITS IMPORTANCE?
Mathematical method for identifying the location of a point on the earth. It
include the latitude and longitude to tell about the location of any earth feature.
A coordinate system is a framework for defining the relative locations of things in
a given area; for example, an area on the earth’s surface or the earth’s surface as a
whole.
a geographic coordinate system uses a three- dimensional spherical surface to
determine locations on the earth.
4.EXPLAIN THE DIFFERENT TYPES OF
COORDINATE SYSTEM.
Geographic Coordinate System (GCS): this system uses latitude and longitude
angles to specify a point’s location on the ellipsoid’s surface.
Geocentric Coordinates System (GEO): this system uses latitude , longitude and
elevation coordinates to define a point’s position relative to the center of the
earth.
5. EXPLAIN MAP SCALE.
Map scale refers to the relationship between distance on a map and the
corresponding distance on the ground.
Map scale is essential for interpreting and using maps accurately. It helps user
understand the relative sizes of features, distances between locations, and the
level of details representing on the map.
6.WHAT IS SCALE FACTOR.
Projection
Latitude
Longitude
Elevation
Accuracy
Purpose of map or image
7.DEFINE MAP PROJECTION.
It is the system of transformation of the spherical surface onto plane surface. It is
carried out by an orderly and systematic representation of the parallels of latitude
and the meridians of longitude of the spherical earth or part of it on a plane
surface on a conveniently chosen scale.
8. WHAT IS THE IMPORTANCE OF MAP
PROJECTION.
I. Visualization and communication
II. Understanding and orientation
III. Geographic information system
IV. spatial analysis measurement
V. Map designing
9. EXPLAIN THE TYPES OF MAP PROJECTION
IN DETAIL?
1. Cylindrical Projection: these projection involved wrapping a cylinder around the earth and
projecting its feature on to the cylindrical surface. Example are the Mercator, Transverse Mercator
and Miller cylindrical projection.
2. Conic Projection: for these projections, a cone is placed over the earth and its feature are
projected onto the cylindrical chronicle surface. Common example are the Lambert conformal
conic and Albers equal area conic projection.
3. Azimuthal projection: also referred to as planar or zenithal projection, these use are flat plane
that touches the earth at single point, projecting the earth's feature on to the plane. Azimuthal
equidistant, stereographic and orthographic projection are examples.
4. Pseudo cylindrical projection: these projection resemble cylindrical projections but employ
curved line instead of straight lines for Meridian and parallels. The Sinusoidal, Mollweide and
Goode Homolosine projection are popular example.
10.WHAT ARE THE DISTORTIONS IN MAP
PROJECTION.
Area preserving projection: also called equal area or equivalent projection, these
projections maintain the relative size of different regions on the map.
Shape preserving projection: often referred to as conformal or orthomorphic,
these projections maintain accurate shapes of regions and local angles.
Direction preserving projection: this category includes conformal ,
orthomorphic, and azimuthal projection, which preserve directions but only from
the central point for azimuthal projection.
Distance preserving projection: known as equidisant projection, they display the
true distance between one or two points and all other points on the map.
