This is a simple lecture to introduce a beginner to GIS World. It will guide on the basics to get started with GIS.

1. INTRODUCTION TO GIS
Mr. Franklin Kebungo Ogwankwa
GIS Enthusiast
franklinogwankwa@gmail.com
+254718144060
January, 2021
DISCLAIMER: I don’t have full copyrights of some contents.This is meant to pass knowledge.

2. What is GIS?
GIS as a Science
“Geospatial Information Science is the art and
science(study) involving the frameworks and
understanding of how geographically referenced
data is acquired, processed, manipulated and
shared”
GIS as a System
“Geographical Information System is a computer
based system that is designed to capture,
manipulate, store, share and visualize spatial data”

3. Basic Concepts of GIS as a Science
 Remote Sensing- capturing
data without being in contact
with the phenomena

4. Con’d
 GPS(Global
Positioning
System) – used to
assign each location
on the earth’s
surface
coordinates(x,y,..z)
for purposes of
georeferencing

5. Con’d
 GIS(Geospatial Information
System)- computer-based system
for processing of spatial data

6. Components of GISystem
1. Data- Information about locations on the
earth’s surface.
2. People- this is the skilled manpower that
helps to read and write geoinformation.
3. Hardware- tangible parts of the computer
system through which the GIS software will
operate.
4. Software- the functions and tools that are
needed to process the spatial data
5. Methods- the procedures required from
geographical data capture through to
storage, sharing and visualization.

7. Con’d

8. Spatial Data Types
1. Vector Data
-Made up of grids
-Represent real world features
as Spatial Entities.
a) Points – represented in
form of x,y coordinates
b) Lines – linear in nature,
connecting of points
c) Polygons – when a set of
vertices are joined in a
particular order and closed.
Represent features at a 2D
like buildings, agricultural
fields
2. Raster Data
-Made up of pixels
-Can represent thematic
categories, heights, spectral
value.
a) Discrete Raster-Thematic
or categorical raster usually
consists of integers to
represent values e.g urban
LU, Political Boundaries.
b) Continuous Raster-
Gradual changing data such
as elevation, temperature
and aerial photograph.

9. Topology
 Topology refers to the study of the
mathematics and geometry showing the
spatial relationships within geographic
features and objects.

10. Topological Rules

11. SDI
 Spatial Data
Infrastructure is used
to denote the relevant
base collection of
technologies, policies and
institutional
arrangements that
facilitate the availability of
and access to spatial data
by readers and
writers(people).
Data
People
Institutional
Arrangements
Technologies
Policies

12. Application of GIS
 GIS and Emergency Response
1. Crime Mapping
2. Accident Management
3. Flood risk management
 GIS and Resource Management
1. Mineral exploration
2. Environmental planning
3. Land use Land Cover

13. Cont’d
 GIS and Decision Making
1. Precision Agriculture
2. Least Cost
3. Project Management
4. Service Provision

14. THANKYOU
For Any Questions and comments direct them to:
+254718144060
Franklin Ogwankwa