PL254 INTRO. TO GIS & MODELS IN PLANNING

1. PL254 INTRO. TO GIS & MODELS IN PLANNING UNIT 3: BASIC COMPONENTS OF A GIS

2. Hardware for GIS Basic GIS Hardware • High-Speed Computer: • a processor • a big-enough monitor • Printer • Plotter • Scanner • GPS receiver, etc

3. Selected GIS Software 1. ArcGIS • ArcReader • ArcView • ArcEditor • ArcInfo • ArcMap & ArcCatalogue are components of each of these 2. MapMaker

4. UNIT 4: COORDINATE SYSTEMS, MAP PROJECTIONS & MAP SCALES

5. Grid/Coordinate Systems What is a Coordinate System? • A system used to define location in 2-dimensional (e.g. x-y) or 3-dimensional (e.g. x-y-z) space • There are several coordinate systems. The 2 most common coordinate systems used in GIS are: Cartesian Coordinate System and Spherical Coordinate System

6. Grid/Coordinate Systems Cartesian Coordinate System: • A grid system defined by 2 (in the case of 2-dimensional coordinate system) or 3 orthogonal (right-angle) axes that intersect at a defined origin, O(0, 0) or O(x, y, z)

7. Grid/Coordinate Systems Spherical Coordinate System: • It is an angular coordinate system often based on the longitudes and latitudes, measured in degrees-minutes-seconds (DMS) or decimal degrees (DD) • A line through all points of the same longitude from North Pole to South Pole is called a meridian

8. Grid/Coordinate Systems Spherical Coordinate System: • An East-West line through all points of the same latitude is called a parallel • A network of meridians and parallels is called a Graticule

9. Datums What is a Datum? • A datum is a set of reference points on the Earth's surface used to make position measurements and model the shape of the Earth to define a geographic coordinate system. • There are 2 types of Datums: Horizontal Datums and Vertical Datums

10. Datums Horizontal Datums: • used for describing a point on the earth’s surface using a coordinate system (e.g. latitude and longitude). Vertical Datums: • used to measure elevations and depths

11. Map Projections What is a Map Projection? • Transformation of coordinate locations from Earth’s curved surface onto flat maps • Many projected coordinate systems exist, each suitable for particular zones on Earth’s surface for particular purposes

12. Map Projections What is a Map Projection? • The Universal Transverse Mercator (UTM) is a popular/standard projected coordinate system. • UTM is based on a Cartesian (grid) coordinate system

13. Map Projections What is a Map Projection? • It divides the entire world into 120 UTM zones—60 zones in the Northern Hemisphere and 60 zones in the Southern Hemisphere • Most of Ghana falls within a zone called UTM Zone 30 North

14. Map Scales What do you understand by the scale of a map? • the ratio of a distance on the map to the corresponding distance on the ground

15. Map Scales Types of Map Scales 1. Lexical (Statement) Scale: • e.g. 1 cm to 100 m • How would you interpret this scale? 2. Ratio Scale: • e.g. 1/10,000 • How would you interpret this scale?

16. Map Scales Types of Map Scales 3. Representative Fraction: • e.g. 1:10,000 • How would you interpret this scale?

17. Map Scales Types of Map Scales 4. Linear Scale: • E.g. • How would you interpret this scale? Can we convert one scale to another?