Support the spread of “good practice” in generating, managing, analysing and communicating spatial information

Introduction to GIS for the Purpose of Practising PGIS

Introduction to GIS

By: Jon Corbett and Kasondra White

Unit: M12U01

Introduction

• Participatory GIS (PGIS)

• Documenting, presenting and protecting local knowledge

• What is a GIS?

• Representing data

• Quantum GIS

• Participatory mapping and GIS

What is a GIS?

• GIS systems:– capture;– store;– analyse;– manage; and– present geographic data.

What is a GIS?

• GIS packages work with:– maps;– remote sensing;– land surveying;– aerial photography;– databases;– other tools.

What is a GIS?

• GIS applications allow users to:– create queries;– analyse spatial information;– edit data and maps;– present results.

• Information can be presented:– in a map;– in a textual form.

What is a GIS?

• Geospatial data:– information related to a location that can be

expressed using coordinates

• GIS can be used for:– creating maps– visualising the relationship between places

and events– searching for geospatial associations– analysing geospatial data

Representing data

• Kinds of questions that GIS can answer:– What is located at a given point?– What kinds of changes have occurred?– What kinds of patterns exist?– What would happen if some kind of a change

were to occur?

Points, lines and polygons• Points

– one spot on a map

– represent exact locations

• Lines

– string of points

– can be measured

for distance

• Polygons

– enclosed area

– defined by often

complex boundaries

Data layers

• Features are displayed through data layers

• Contain thematic data

• Layers can be:– turned on or off– placed on top of or below

one another

• Multiple layers can be open at one time

Quantum GIS

• Open source – freely available– supported by a community of programmers

and technicians

• User-friendly

The graphical user interface (GUI)

• Simplifying interactions with software

• Uses:– clickable symbols– text

• Understanding GUI functions is an important part of learning GIS

The graphical user interface

The toolbar

Participatory mapping and GIS

• Does GIS fit with the community’s vision?

• Does GIS directly address mapping needs?

• Is GIS anti-participatory?– expertise required– may require technicians from outside the

community

Participatory mapping and GIS

• Practitioners of participatory development should avoid technologies that are:– complex– expensive– time-consuming

• May, however, still be useful

• “Chauffeur-driven” systems

GPS• Displays points collected through a

Global Positioning System (GPS)• Captures coordinates of locations

of interest• Points can be uploaded and

displayed• Useful for depicting locations or

boundaries