the perfect land development plan for Project Site X, Y & Z, we will explore various methods of land assembly and public-private partnerships to secure the remaining 20 hectares of land for the project

1. 1
Map Projection and Coordinate System
Lecture Three

2. 2
Presentation Outline
● Map Projection
Choosing a Map Projection
Types of Map Projection
Classification of Map Projections
● Coordinate Systems
Geographic Coordinate System
Cartesian Coordinate System
Universal Transverse Mercator

3. 3
Map Projection
What is Map Projection
 Map projection: Portrays a three-dimensional object,
such as the Earth’s globe, in a two-dimensional format
(3D TO 2D)
Projections cause distortion.
shapes, area, distances and directions distortion

4. 4
Why do we need a projection?
A. Map and its use
– We must choose an appropriate projection for the map to
communicate effectively
– Part of good cartographic design (w/o projection it is
incomplete!!)
B. Sharing/receiving geographic data
– we must know the map projection in which the data are stored.
– Overlay map of same area is possible with similar projections
C. For manipulation /operation/
– Data often comes in geographic, or spherical coordinates (latitude and
longitude) and can’t be used for area calculations.
– In most GIS software applications quantities measurement is possible in
projected coordinate (area, length, volume etc…)

5. 5
Map projections Distortions
 The projection process will distort
one or more of the four spatial
properties listed below.
 Distortion of these spatial
properties is inherent in any map.
– Shape
– Area
– Distance
– Direction/Azimute/
 (SADD)

6. 6
Choosing a Map Projection
 Considerations:
NB. Choosing a map projection involves more than planning; it involves
decisions and an understanding of how best to represent the spheroid
Desired properties to exhibit(display)
Purpose of the application( small vs large mapping)
Determine features to be preserved
(area, Distance, shape, direction)
Features that can be compromised
(Area, Length, Shape, Direction)
NB. Preserving accurate representations of all four elements simultaneously is impossible.

7. 7
Types of Map Projection
 Three distinct types
of projections:
Conic
Cylindrical
Planar

8. 8
 Four primary projection classifications
Equidistant
Equal-Area
Azimuthal
Conformal
Classification of Map Projections

9. 9
1. Conformal Projections (shape)
 Preserve local shape and area useful for navigational charts and weather
maps.
 Shape is preserved for small areas, but the shape of a large area, such as a
continent, will be significantly distorted.
 The drawback is that the area enclosed by a series of arcs may be greatly
distorted in the process.
2. Equal area projections (preserve area)
 Many thematic maps use an equal area projection.
 To do this, the other properties of shape, angle, and scale are distorted.
 Especially maps of smaller regions, shapes are not obviously distorted
Classification of Map Projections cont..

10. 1
0
3. Equidistance projections
 Preserve the distances between certain points
 A projection is considered equidistant when scale is true along at least one line
(a focal line) or from one or two points (focal points) to all other points on the
projected surface
4. Azimuthal Projections
 In an azimuthal projection, all points in relation to a central point (such as a
pole) are not deformed during the projection process from globe to plane.
 The central point occurs at the intersection of the tangential plane to the
ellipsoid of revolution
Classification of Map Projections cont..

11. 1
1
Coordinate System
Definition
 A coordinate system is the reference system upon which
coordinates are defined
 A coordinate is a number set that denotes a specific
location within a reference system
 x-y set ([x, y]) in a two-dimensional system
 x-y-z set ([x, y, z]) in a three-dimensional system
 Planar systems have x and y-axes, while three-
dimensional systems have an additional z-axis for
height

12. 1
2
Coordinate System…
Types
 Some of the coordinate systems include:
Earth-based Geographic Coordinate System
Vector-based Cartesian Coordinate Systems
Zone-based Universal Transverse Mercator
.U.S.-based State Plane Coordinate System

13. 1
3
Types cont…
A. Geographic Coordinate System
 Geographic Coordinate System: is a three
dimensional positional reference that utilizes
latitude, longitude, and ellipsoidal height

14. 1
4
Types cont…
B. Cartesian Coordinate System
 Cartesian System: is a reference structure in
which point positions are measured along
intersecting planes in two and three dimensions
2Dimension 3Dimension

15. 1
5
Types cont… Universal
C. Transverse Mercator
 UTM Coordinate System: is set upon a zoned grid,
which divides the Earth into 60 equal zones that
are all 6° wide in longitude (east-west)
- Ethiopia is situated in
the UTM Zones of 36o,
37o & 38o
- The Conventional UTM
Projection Parameter
for Ethiopia is Adindan
UTM Zone, 36 & 37,38
respective to the Zones.
The measurement unit is
metres.

16. 1
6
UTM